Increased volume of untreated and inadequately treated municipal wastewater undermines the circular economy potential of wastewater resources, particularly in low-income region. This present study focused on and evaluated the performance of native microalgae-activated sludge (MAS) growth for tertiary treatment of anaerobically digested wastewater from an upflow anaerobic sludge blanket (UASB) in an outdoor lab-scale photobioreactors (2 L). Seven conditions with distinct inoculum concentrations were operated in batch mode in triplicate for 5-days hydraulic retention time (HRT) at 11.5:12.5 Photo-hours. MAS inoculum concentration influenced treatment outcome. The best performance was observed in MAS concentration 0.10/0.20 g L-1, with cell density count (2.03 x 107 cells mL-1), biomass productivity 0.125 g TSS L-1 d-1 and total phosphorus uptake (85.07%), total nitrogen uptake (66.14%). Logarithmic removal (Log-Re) of bacterial pathogens (water quality indicators) showed Log-Re ((3.4 for total coliforms (1.37E+02 CFU 100 mL-1) and 4.7 for Escherichia coli (0.00E+00 CFU 100 mL-1)). Results revealed optimum remediation performance and nutrients’ recovery potential with appropriate inoculum concentration, in admiration to advancing the science of circular economy.

Due to rapid urbanization, the quantity of wastewater treatment plants (WWTP) has increased, and with it the amount of waste generated by them. Sustainable management of this waste can lead to the creation of energy-rich biogas through the fermentation process. This review presents recent advances in the anaerobic digestion process resulting in greater biogas production. Disintegration techniques for enhancing waste activated sludge fermentation can be generally partitioned into biological, physical and chemical, each of which are covered in this review. These disintegration techniques were compared mainly in terms of their biogas yield. It was found that ultrasonic and microwave disintegration provides the highest biogas yield (>500%); however, they are also the most energy demanding (>10,000 kJ kg-1 total solids).

A large number of microplastics (MPs) have been found in various stages of wastewater treatment plants, which may affect the functional microbial activity in activated sludge and lead to unstable pollutant removal performance. In this study, the effects of different concentrations of polylactic acid microplastics (PLA MPs) on system performance, nitrification and phosphorus (P) removal activities, and extracellular polymeric substances (EPS) were evaluated. The results showed that under the same influent conditions, low concentrations (50 particles/(g TS)) of PLA MPs had no significant effect on effluent quality. The average removal efficiencies of chemical oxygen demand, phosphate and ammonia were all above 80%, and the average removal efficiencies of total nitrogen remained above 70%. High concentrations (200 particles/(g TS)) of PLA MPs inhibited the activities of polyphosphate accumulating organisms (PAOs) and nitrifying bacteria. The specific anaerobic P release rate decreased from 37.7 to 23.1 mg P/(g VSS·h), and the specific aerobic P uptake rate also decreased significantly. The specific ammonia oxidation rate decreased from 0.67 to 0.34 mg N/(g VSS·h), while the change in specific nitrite oxidation rate was not significant. The dosing of PLA MPs decreased the total EPS and humic acid content. As the concentration of PLA MPs increased, microbial community diversity increased. The relative abundance of potential PAOs (i.e., Acinetobacter) increased from 0.08% to 12.57%, while the relative abundance of glycogen accumulating organisms (i.e., Competibacter and Defluviicoccus) showed no significant changes, which would lead to improved P removal performance. The relative abundance of denitrifying bacteria (i.e., Pseudomonas) decreased from 95.43% to 58.98%, potentially contributing to the decline in denitrification performance.

Fats and oils are the most common contaminants in wastewater and are usually discarded through physical processes. This paper studies its elimination through an environmentally friendly biological treatment, yielding good results on both laboratory scale and in the field. In this study a comparative evaluation of the biodegradation of fats and oils in two scenarios were developed in an activated sludge plant at laboratory scale, and a wastewater treatment plant. The full-scale values for some key parameters are compared, such as the oil concentration in the influent and effluent, mass loading and removal efficiency and biodegradation systems. Activated sludge plant at laboratory scale working on a mass load range from 0.2 to 0.8 (kg COD / day / kg MLSS) initially reaches levels of 75% biodegradation thereafter influent concentration is increased and thereby the mass load is increased in a range of working system under high load and biodegradation rates ranging from 71 to 64% are achieved. The actual system consists of a treatment plant wastewater with an aerobic digester for sludge treatment. Fats and oils are retained in a previous degreaser to biological treatment and subsequently sent to the aerobic sludge digester, constituting of thus on a single substrate, resembling an activated sludge plant with extended aeration mode, and levels of biodegradation in the range of 69 to 92%. From this work, we can say that the choice of biological treatment for fats and oils is feasible and adequate. Furthermore, the biomass presents great adaptability to the oil substrate, favored in this case for being the only source of carbon, therefore fats and oils should be removed using biological treatment, instead of the flotation procedure or at most using it as an intermediate process

The structure of existing activated models is inherently deficient in reflecting the major role of the membrane filtration. This study developed and proposed a novel model, MASM, for the membrane activated process. The effective filtration size imposed by the membrane module, entrapping larger size particles was adopted as the basis of the proposed model. The model defined a modified COD fractionation, accounting for the captured COD fractions as additional model components and utilizing related mass balance relationships. It was implemented for testing the fate of soluble hydrolysable COD and system performance of super-fast membrane activated sludge based on real data for the characterization and process kinetics of domestic sewage and denim processing effluents. Model evaluation was carried for parallel systems with gravity settling and membrane filtration operated at a sludge age range of 0.5-2.0 d. Results reflected significantly better performance of super-fast membrane activated sludge system for both wastewaters, underlining that it was crucially important to account for the captured COD fractions to provide an accurate evaluation of system behavior and effluent quality. This should also be identified as the major shortcoming of the ASM models for evaluating and predicting system performance of activated sludge configurations with membrane separation.

Electrochemical methods are used for the treatment of both municipal and industrial wastewater, either independently or in conjunction with biological methods. This conjunction is used for pretreatment or posttreatment of biologically treated wastewater. In our work, we focused on the combination of these processes, where pre-electrolysis was used to produce dissolved iron before the activation process. Electrolysis was also directly introduced into the activation using either iron or carbon electrodes. The surface of one iron electrode was 32.2 cm2, the applied voltage was 21 V, and the supplied current was 270 mA. The surface of one carbon electrode was 7.54 cm2, the supplied current was 82.5 mA, and the applied voltage was 21 V. From laboratory research on the treatment of synthetic municipal wastewater using a combination of electrolysis and activation processes, it resulted that the use of iron electrodes increased the efficiency of phosphorus removal compared to its precipitation with iron salts. The electrolysis had a positive effect on the sedimentation properties of sludge and the destruction of filamentous microorganisms. Electrolysis negatively affected the respiration rates of activated sludge and the efficiency of denitrification. However, it did not have a negative impact on the nitrification activity of the sludge.

The quality of waste activated sludge produced in urban wastewater treatment systems varies according to the efficiency of the operation of treatment units along the content of microflora and organic carbon. However, these represent a biogas-energy alternative through anaerobic co-digestion, contributing to reducing the environmental impacts caused by their inadequate disposal. Biogas production by the Two-stage production method in batch digesters was evaluated by two qualities of waste activated sludge (SLB50 y SLB90) and with a mixture of two co-substrates: cattle manure (CEV50 y CEV90) and residual edible oil with mixing, pH and temperature control. Bacteria in good quality sludge (SLB90) showed a faster adaptation of 2 days than those in low quality (SLB50) with 25 days lag phase. The highest CH4 production was for SLB90 (303.99cm3 d-1) compared to SLB50 (4.33 cm3 d-1); while cow manure sludge mixture (CEV90) contributed to increasing production of CH4 (42 422.8 cm3 d-1) compared to CEV50 (12 881.45 cm3 CH4 d-1), while in residual edible oil mixture they were 767.32 cm3 d-1 and 211.42 cm3 d-1 for CAV90 y CAV50, respectively. The addition of sludge co-substrates improves the nutrient balance, C/N rate and micro flora diversity; consequently methane production improves too; this methodology could be integrated into concepts of Circular economy.

Integrated Fixed Film Activated Sludge (IFAS) technology greatly enhances nitrogen removal effectiveness and treatment capacity in municipal wastewater treatment plants, addressing the issue of limited land availability. Hence, this method is appropriate for treating household wastewater from office buildings. The research was conducted at the wastewater treatment plant in an office building in Ho Chi Minh City, Vietnam. Experiments were conducted to ascertain the most favorable working conditions, including Hydraulic Retention Time (HRT), alkalinity dosage, and Dissolved Oxygen (DO). According to the study, the IFAS system had the highest nitrogen removal effectiveness when operated at a hydraulic retention time (HRT) of 7 hours, an alkalinity dose of 7.14 mgCaCO3/mgN-NH4+, and a dissolved oxygen (DO) value of 6 mg/L. The nitrification efficiency ranges from 89.2% to 98.8%. The nitrate concentration post-treatment is within the range of 27 – 45 mg/L, which is lower than the allowable discharge limit of 60 mg/L as per Vietnam's wastewater discharge requirements. The research findings have enhanced the efficiency of the office building management process, thereby promoting the sustainable growth of society.

The volatile fatty acids (VFAs) productions, as well as particulate organics decomposition, soluble chemical oxygen demand (SCOD) yield, and the VFAs production pathways, of mesophilic and thermophilic anaerobic fermentation were investigated. Batch experiments showed that the decomposition rate of volatile suspended solids (VSS), particulate carbohydrate (P-C) and particulate protein (P-P) followed the first-order kinetic model at different temperature. However, the intermediates， accumulated in the process of protein or carbohydrate digestion had a more significant inhibitory effect on the production of VFAs during the mesophilic anaerobic acidification process. Thermophilic fermentation led to more accumulation of VFAs compared to mesophilic fermentation. Then 13C stable isotope labeling experiment demonstrated that, acetic (HAc), propionic (HPr) and butyric (HBu) could be produced from carbohydrate and protein digestion, but valeric (HVa) was only generated from the degradation of protein. Finally, the possible pathway of HVa synthesis was proposed.

High-strength wastewaters from a variety of sources, including the food industry, domestic septage and landfill leachate, are often hauled to municipal wastewater treatment plants (WWTPs) for co-treatment. Due to their high organic loadings, these wastewaters can cause process upsets in both the WWTP’s liquid and solids treatment trains and consume organic treatment capacity, leaving less capacity available to service customers in the catchment area. A novel pre-treatment method, the Waste Activated Sludge-High Rate (WASHR) process, is proposed to optimize the co-treatment of high-strength wastewaters. The WASHR process combines the contact stabilization and sequencing batch reactor processes. It utilizes waste activated sludge from the municipal WWTP as its biomass source, allowing rapid start-up. Bench scale treatment trials of winery wastewater confirm the WASHR process can reduce loadings on the downstream WWTP’s liquid treatment and solids treatment trains. A case study approach is used to confirm the economic viability and environmental sustainability of the WASHR process compared to direct co-treatment using life cycle cost analyses and greenhouse gas emissions estimates.

While molecular methods have begun to transform ecology, most algal biodiversity is still studied using the classical approach of identifying microalgae by light microscopy directly in sample material or using cultures. In this study, we compare both approaches (light microscopy and metagenomics as a molecular approach) using freshwater ponds of the Eifel National Park in Germany as a case study. The ponds were found to be rich in desmids by light microscopy. A total of 299 species representing 81 genera were identified by light microscopy. While the molecular method does not currently allow species identification in most cases, we were able to identify 207 different algal genera. 157 genera were detected only by metagenomics, 50 genera with both methods and 31 genera were found by light microscopy, highlighting the need to continue using light microscopy in addition to a molecular approach. The metagenomics method has several advantages over the light microscopy method: 1) deeper assessment of alpha biodiversity 2) better abundance numbers 3) complete coverage of all living matter. The latter is also a significant improvement over metabarcoding, as universal PCR primers are not available.

Molybdenum (Mo) is vital for the activity of a small but essential group of enzymes called mo-lybdoenzymes. So far, specifically five molybdoenzymes have been discovered in eukaryotes: nitrate reductase, sulfite oxidase, xanthine dehydrogenase, aldehyde oxidase, and mARC. In order to become biologically active, Mo must be chelated to a pterin, forming the so-called Mo cofactor (Moco). Deficiency or mutation in any of the genes involved in Moco biosynthesis results in the simultaneous loss of activity of all molybdoenzymes, fully or partially preventing the normal development of the affected organism. To prevent this, the different mechanisms in-volved in Mo homeostasis must be finely regulated. Chlamydomonas reinhardtii is a unicellular, photosynthetic, eukaryotic microalga that has produced fundamental advances in key steps of Mo homeostasis over the last 30 years, which have been extrapolated to higher organisms, both plants and animals. These advances include the identification of the first two molybdate transporters in eukaryotes (MOT1 and MOT2), the characterization of key genes in Moco biosynthesis, the identification of the first enzyme that protects and transfers Moco (MCP1), the first characteriza-tion of mARC in plants, and the discovery of the crucial role of the nitrate reductase-mARC complex in plant nitric oxide production. This review aims to summarize all these advances made using C. reinhardtii as a model organism in Mo homeostasis and suggest how this microalga can continue to contribute to progress in this field.

Fermentation is the oldest method used globally to process and preserve food while enhancing its nutraceutical profile. Alga-based fermented products have freshly been produced and tested due to rising curiosity in healthy supportable diets, which stresses the progress of advanced methods in food manufacture, functioning for both human health and Earth sustainability. Current applications have attention on the existence of numerous composites, including polyphenols and polyunsaturated fatty acids, that are treasured for food and pharmaceutical manufacturing. Both micro and macroalgae have expanded consideration as fermentation substrata, as they are measured as a maximum and acceptable basis of bioactive composites. Fermentation of microalgae has concentrated either on making biofuel or on procuring composites with bioactive assets, like antioxidant ability, antimicrobial capacity and anti-inflammatory probables. The objective of this review is to present a note on microalgae fermentation to acquire diverse valued composites with bioactive abilities. Furthermore, the methods of fermentation, species of algae employed in fermentation, fermentation circumstances, and bioactive properties of the derived bioactive composites have conversed.

Microalgae biomass is considered a promising alternative feedstock for biodiesel production due to its high productivity of neutral lipids, specially under abiotic stress conditions. Among the unicellular microalgae that show this characteristic, Chlamydomonas reinhardtii appears as one of the most important model species that have increased lipids production under abiotic stress conditions. In this study, we show that cells cultivated under mixotrophic condition supplemented with 0.1 M of NaCl rapidly raises their amount of neutral lipids in C. reinhardtii without reduction of their cellular growth rate, being therefore a promising condition for biomass towards bioenergy production. The nuclear proteome of these cells was investigated where we identified 323 proteins with an enrichment of almost 60% of nuclear proteins in the total dataset. We found 61 proteins differentially regulated upon salt treatment, including proteins annotated in functional categories related to translation and nucleosome assembly functions, among others. Additionally, we identified Transcription factor proteins (TFs) and analyzed their likely Transcription factors-binding regulatory elements identifying target genes related to lipids metabolism and kinase functions, indicating possible regulatory pathways of lipids biosynthesis. Together these data can help understand regulatory nuclear mechanisms leading to an increase of lipids in the first 24h of salt stress 0.1M NaCl.

Microalgae are recognized as a third generation feedstock for biofuel production due to its rapid growth rate and lignin-free characteristic. In this study, the lipid extracted microalgae biomass residues was used as the material to produce isoprene, α-pinene and β-pinene with the engineered E. coli strain. We adopted an optimal sulfuric acid hydrolysis method to convert holocellulose into fermentable sugar efficiently (6.37 g/L) and explored a novel detoxification strategy (phosphoric acid/calcium hydroxide) to remove inhibitors notably. 55.32 % acetic acid, 99.19 % furfural and 98.22 % 5-HMF were cut down with the phosphoric acid/calcium hydroxide method, and the fermentation concentration of isoprene (223.23 mg/L), α-pinene (382.21 μg/L) and β-pinene (17.4 mg/L) using the detoxified hydrolysate as the carbon source account for approximately 86.02 %, 90.16 % and 88.32 % of those produced by the engineered E. coli strain fermented on pure glucose, respectively.

Microalgae are known as a rich source of bioactive compounds which exhibit different biological activities. Increased demand for sustainable biomass for production of important bioactive components with various potential especially therapeutic applications has resulted in noticeable interest in algae. Utilization of microalgae in multiple scopes has been growing in various industries ranging from harnessing renewable energy to exploitation of high-value products. The focuses of this review are on the isolation of bioactive compounds from microalgae regarding different metabolites which are currently used and new possible applications of the compounds in industries and future prospects. Moreover, this work discusses the advantage, potential new beneficial strains, applications, limitations, research gaps and future prospect of microalgae in industry.

After the ban on tributyltin-based antifouling paints, DCOIT (4,5-Dichloro-2-octylisothiazol-3(2H)-one) became one of the most used antifouling biocides. DCOIT is a pseudo-persistent contaminant in port areas and is toxic to non-target species, but its ability to bioaccumulate and be transferred along the trophic chain remains unknown. This study aimed to preliminarily investigate the bioaccumulation, trophic transfer, and biomagnification of DCOIT and SiNC-DCOIT (DCOIT immobilized in silica mesoporous nanocapsules) from the microalga Tetraselmis chuii to the mussel Mytilus galloprovincialis during exposure experiments considering 24 h of uptake followed by 72 h depuration. Mussels rapidly internalized and metabolized both DCOIT and SiNC-DCOIT. The predator-prey biomagnification factors (BMFTL) suggested that both forms of the biocide can be trophically transferred, with higher concentrations of DCOIT and SiNC-DCOIT in mussels than in microalgae (BMFTL > 1). However, the bioaccumulation and bioconcentration factors indicated a low bioaccumulation capability in the short term, suggesting that the depuration rate overcomes the uptake. Our findings contribute to the development of environmental risk assessments for DCOIT and SiNC-DCOIT, but do not exclude the possibility of DCOIT bioaccumulation in the long-term in areas with constant input of DCOIT. Further studies are needed to understand these processes under continuous exposure scenarios to DCOIT.

Plant-based protein sources derived from microalgae offer promise as low-carbon emission and nutrient-dense sources for human consumption. The current management of microalgae cultivation relies heavily on manual microscopic examination in order to identify desired and competing species, as well as predators. In this study, we trained and tested a transfer learning model modified from EfficientNetV2 B3 on 434 and 161 prospectively acquired images of the preferred Nannochloropsis sp microalgae and competitor Spirulina, respectively, and achieved >98% classification for both species on tenfold cross-validation. The model was further enhanced with gradient-weighted class activation mapping, which allowed visualization of regions of the input images that were relevant to the classification, thereby improving its explainability. In this paper, we demonstrate that a simple deep transfer learning model can be used to identify microalgae species. The application addresses the practical need for robust automated monitoring of microalgae populations on industrial microalgae farms.

The production of fatty acids ethyl esters (FAEEs) to be used as biodiesel from oleaginous microalgae shows great opportunities as an attractive source for the production of renewable fuels without competing with human food. To ensure the economic viability and environmental sustainability of the microbial biomass as a raw material, the integration of its production and transformation into the biorefinery concept is required. In the present work, lipids from wet Isochrysis galbana microalga were extracted with ethyl acetate with and without drying the microalgal biomass (dry and wet extraction method, respectively). Then, FAEEs were produced by lipase-catalyzed transesterification and esterification of the extracted lipids with ethanol using lipase B from Candida antarctica (CALB) and Pseudomonas cepacia (PC) lipase supported on SBA-15 mesoporous silica functionalized with amino groups. The conversion to FAEEs with CALB (97 and 85.5 mol% for dry and wet extraction, respectively) and PS (91 and 87 mol%) biocatalysts reached higher values than those obtained with commercial Novozym 435 (75 and 69.5 mol%). Due to the heterogeneous nature of the composition of microalgae lipids, mixtures with different CALB:PC biocatalyst ratio were used to improve conversion of wet-extracted lipids. The results showed that a 25:75 combi-lipase produced a significantly higher conversion to FAEEs (97.2 mol%) than those produced by each biocatalyst independently from wet-extracted lipids and similar ones than those obtained by each lipase from the dry extraction method. Therefore, that optimised combi-lipase biocatalyst, along with achieving the highest conversion to FAEEs, would allow improving viability of a biorefinery since biodiesel production could be performed without the energy-intensive step of biomass drying.

Serine proteases regulate cell functions through G protein-coupled protease-activated receptors (PARs). Cleavage of one peptide bond of the receptor amino terminus results in the formation of a new N-terminus ("tethered ligand") that can specifically interact with the second extracellular loop of the PAR receptor and activate it. Activation of PAR1 by thrombin (canonical agonist) and activated protein C (APC, noncanonical agonist) was described as biased agonism. Here we have supposed that synthetic peptide analogues to the PAR1 tethered ligand liberated by APC could have neuroprotective effects like APC. To verify this hypothesis a model of the ischemic brain impairment based on glutamate (Glu) excitotoxicity in primary neuronal cultures of neonatal rats has been used. It was shown that nanopeptide NPNDKYEPF-NH2 (AP9) effectively reduced the neuronal death induced by Glu. The influence of AP9 on cell survival was comparable to that of APC. Both APC and AP9 reduced the dysregulation of intracellular calcium homeostasis in cultured neurons induced by excitotoxic Glu (100 µM) or NMDA (200 µM) concentrations. PAR1 agonist synthetic peptides might be a noncanonial PAR1-agonist and a basis of novel neuroprotective drugs for disorders related to Glu excitotoxicity such as brain ischemia, trauma and some neurodegenerative diseases.

Microalgae and their bioproducts hold significant potential across various applications, for instance, in wastewater remediation, CO2 fixation, and the synthesis of nutraceuticals, pharmaceuticals, and biofuels. The production of these organisms heavily relies upon environmental conditions, including factors like temperature, light, and nutrient supply, which can significantly impact growth. Furthermore, the limitations in nutrients or certain extreme environments can result in productivity increases. As such, microalgae growth systems have become a critical consideration for both research and industry. Both open and closed systems, such as raceway ponds and photobioreactors, respectively, have their own advantages and drawbacks in microalgae cultivation. However, for microalgae growth, photobioreactors may address most concerns, as the system has a lower risk of contamination and can deliver specific growth factors in a controlled manner. This review will summarize the growth and incubation factors of microalgae and the uses of bioreactors in both research and industrial capacities.

The present study aimed to investigate the effect of solution of ethanol extractions of different microalgae species: Spirulina sp., Dunaliella sp. and Chlorella sp. on the accumulation of biologically active compounds in tomato fruits. Ethanol solution as well as treatment with drinking water were used as a control. Tomato cultivar ‘Belle’ F1 (Enza Zaden) was grown in 25 L pots, in peat substrate (pHKCl 5.5, producer Laflora LTd), polycarbonate greenhouse. Chemical composition – total carotenoids, lycopene and β-carotene content, total phenolics and anthocyanins, organic acids, vitamin C as well as dry matter, pH and soluble solids content – was determined in tomato fruits at the stage of full ripen. The influence of tested extracts on biologically active compounds on quality parameters of tomatoes was different, but no negative effect was observed. As only pH values as well as total phenol content and total soluble solids had statistically significant differences, results can be described with genetical stability of the cultivar.

Photodynamic therapy has emerged as a non-invasive treatment modality for various diseases, leveraging photosensitizing compounds to induce localized cytotoxicity upon light activation. This review explores the isolation and characterization of photosensitizing compounds sourced from microalgae, focusing on their potential applications in photodynamic therapy. Microalgae represent a rich source of bioactive molecules, including chlorophylls, phycobiliproteins, and carotenoids, which exhibit inherent photosensitizing properties. Methodologies for the extraction and purification of these compounds from different microalgal species are discussed, emphasizing the importance of optimizing extraction techniques to enhance yield and purity. Characterization techniques such as UV-Vis absorption spectroscopy, fluorescence spectroscopy, and mass spectrometry are highlighted for elucidating the chemical structures and photophysical properties of isolated compounds. Furthermore, the review examines the photodynamic efficacy of microalgae-derived photosensitizers through in vitro and in vivo studies, assessing their cytotoxic effects on cancer cells and antimicrobial activity against pathogens. The integration of microalgae-derived photosensitizers into PDT protocols represents a promising avenue for developing sustainable and effective therapeutic strategies, underscoring the potential of these natural compounds in advancing biomedical applications.

Fish kills in Southeast Asia are frequently associated with harmful algal blooms (HABs) and cause significant ecological and economic impacts. This paper serves as a review of fish kill events with focus on those related to HABs within the region. It examines the causative algal species, known mechanisms of fish mortality, and socio-economic consequences. Fish kills have been reported across multiple countries within Southeast Asia, with notable hotspots in the Philippines, Malaysia, Singapore, Indonesia, and Thailand. The common harmful microalgal species span a diverse group including dinoflagellates (Karenia spp., Karlodinium spp., Margalefidinium polykrikoides, Noctiluca scintillans), raphidophytes (Chattonella spp.), diatoms (Skeletonema spp. and Chaetoceros spp.), and cyanobacteria (Trichodesmium spp.). These microalgae lead to fish kills through mechanisms such as hypoxia, physical gill damage, and ichthyotoxin production. Freshwater fish kills linked to HABs have also been documented for the Philippines, but there is no or limited information for the region. Our review highlights the widespread and recurring nature of fish kills, their impact on fisheries and aquaculture, and challenges in managing and mitigating their effects. There are efforts at enhancing management and mitigation using clay and early-warning systems. However, it is essential to further improve monitoring efforts, the development and deployment of early-warning systems, and viable and holistic mitigation strategies to protect the region’s aquatic resources and dependent communities, especially as aquaculture and coastal development are increasing concurrent with a changing climate that can exacerbate the risks of fish kills and HABs in Southeast Asia.

Chlorella vulgaris has considerable promise as a raw material for biofuel production since it has a high productivity per unit area, has a minimum influence on the environment, and does not significantly affect food security. Nevertheless, the low fatty content of their biomass poses a considerable economic obstacle for commercialization. Increasing the amount of biomass and lipids produced by these algae is essential for improving the economic feasibility of using them as biofuel sources. This review highlights the significance of identifying appropriate algal strains, namely those found in local environments, and utilising mutagenesis and genetic engineering techniques to create 'platform strains'. Prior endeavours have primarily concentrated on altering environmental and dietary parameters to enhance the production of biomass and lipids. Here, we review a scientific literature that examines biotechnological approaches and develops methodologies designed to increase lipid production, emphasising the importance of aligning engineering efforts with breakthroughs in DNA manipulation tools. In addition, the review research evaluates the present economic and commercial situation of algal biorefineries, including any related disadvantages. In summary, this thorough research highlights the importance of using creative methods to tackle the intricacies of lipogenesis and enhance the economic viability of producing biofuels from algae.

In this study, we used Chlorella vulgaris (C.vulgaris) grown in the dairy wastewater as biomass to produce a third-generation biodiesel. The lipids were extracted from the biomass and the biodiesel obtained by transesterification. Following ASTM and EN guidelines, the biodiesel was assessed along with its density, viscosity, heating value, and flash point. Gas chromatography was used to evaluate the concentration, composition, and type of fatty acid methyl esters. The results showed a biodiesel yield of 93% with a composition of 33% saturated, 28% monounsaturated, and 37% polyunsaturated. Engine testing was carried out to monitor the levels of CO, CO2, NOx, and smoke emissions as well as to assess the biodiesel performance. Results demonstrate the possibility of producing third-generation biodiesel from C. Vulgaris cultivated in dairy wastewater. The proposed process valorize the dairy wastewater and might represent an alter-native approach for biodiesel production and the disposal of the wastewater.

Bisphenol A analogs (BPA analogs) are emerging contaminants with a rising production caused by the replacement of BPA with these compounds. The increased production of BPA analogs is leading to an increased release into various ecosystems, including sea. The aim of this study was to evaluate the biological effects of BPA analogs on a primary producer, the diatom Phaeodactylum tricornutum Bohlin. Three different BPA analogs (BPAF, BPF, and BPS) and their mixture were tested at the environmental relevant concentration of 300 ng/L. Growth curve, cell size and several biomarkers of oxidative stress and oxidative damage were measured. Our results indicated that the tested compounds caused alteration of the growth and induced oxidative stress altering many antioxidant enzymes. However, no oxidative damages were observed.

(1) Background: Microalgae cultures are greatly facilitated if growers can easily and economically ascertain the quantitative and qualitative status of the culture continuously with satisfactory ac-curacy. (2) Methods: The locally isolated microalgae Dunaliella sp. and Anabaena sp. were cultured in small volumes with 2 intensities of white light (2000 and 8000 lux) and with green, blue and red light and the increase of their biomass and pigments was studied. Pigment analyses, continuous recordings of absorption spectra and calibration curves were performed. (3) Results: The intensity of 8000 lux white light yielded the highest increase in biomass, chlorophylls and carotenoids in Dunaliella sp. while 2000 lux and green light caused the greatest increase in biomass and phy-cocyanin in Anabaena sp. From the examination of the absorption spectra, the evolution of the pigment content can be estimated and both pigments and biomass are correlated very satisfactorily with the wavelength of 750 nm. (4) Conclusions: The use of absorption spectra as an easy, fast and economical method can be a useful tool for a good approximation of the state of the microalgae culture. This is clearly shown when the spectra of the culture under different lighting colors are compared which have a catalytic effect on the level of the pigments leading to the increase in carotenoids and phycocyanin of the green light.

Microalgae are used in various biotechnological processes, such as biofuel production due to their high biomass yields, agriculture as biofertilizers, production of high-value-added products, de-contamination of wastewater, or as biological models for carbon sequestration. The number of these biotechnological applications is increasing, and as such, any advances that contribute to reducing costs and increasing economic profitability can have a significant impact. Nitrogen fixing organisms, often called diazotroph, also have great biotechnological potential, mainly in agri-culture as an alternative to chemical fertilizers. Microbial consortia typically perform more com-plex tasks than monocultures and can execute functions that are challenging or even impossible for individual strains or species. Interestingly, microalgae and diazotrophic organisms are capable to embrace different types of symbiotic associations. Certain corals and lichens exhibit this sym-biotic relationship in nature, which enhances their fitness. However, this relationship can also be artificially created in laboratory conditions with the objective of enhancing some of the biotech-nological processes that each organism carries out independently. As a result, the utilization of microalgae and diazotrophic organisms in consortia is garnering significant interest as a potential alternative for reducing production costs and increasing yields of microalgae biomass, as well as for producing derived products and serving biotechnological purposes. This review makes an effort to examine the associations of microalgae and diazotrophic organisms, with the aim of highlighting the potential of these associations in improving various biotechnological processes.

Natural astaxanthin is a precious substance obtained from some organisms such as microalgae. This plant has many benefits for humans, so research into its cost-effective and economical production has recently increased. For this purpose, some methods such as the use of different culture media, gene engineering, different stresses, nanoparticles, bio acids, and phytohormones are important. Accordingly, this review study was conducted to demonstrate the effect of the factors mentioned above for the high production of astaxanthin in microalgae, especially Haematococcus pluvialis (H.p).

NH4Cl is one of the nitrogen sources for microalgal cultivation. However, excessive amounts of NH4Cl affects microalgal physiology and biomass contents. In this study, the effects of ammonium on microalgal growth and TAG content in the green microalga (Chlamydomonas reinhardtii) was investigated. Microalgal growth and TAG content under photoautotrophic conditions were found to be unchanged with 17 mM of ammonium, while this compound interfered with microalgal growth and induced TAG content under mixotrophic conditions with acetate supplementation. This suggested that ammonium could induce TAG production when acetate occurred in microalgal cultivation. Further, the effects of two different concentrations of NH4Cl (17 mM and 60 mM) on the cells under mixotrophic conditions were investigated. The results showed that both concentrations reduced microalgal growth, but induced total lipid and TAG content, especially after a 4-day cultivation. The oxygen evolution and Fv/Fm ratio showed that both concentrations completely inhibited the oxygen evolution on Day 4. The 60 mM NH4Cl reduced the Fv/Fm ratio from 0.7 to 0.48 indicating that ammonium supplementation directly affects the microalgae photosynthesis performance. A total of 1782 proteins were successfully identified using proteomics analysis. Among them, there were nine overexpressed proteins and four proteins were underexpressed. Using the protein–ligand interaction analysis, nitrogen metabolism is involved under NH4Cl conditions. This information can provide biochemical knowledge for microalgae development for sustainable energy usage.

Microalgae biomass is a budding raw material for the origination of food, fuel, and other value-added products. However, bulk production of microalgal biomass at commercial level is a herculean task for the current microalgal mass production technologies due to the undesirable contaminations by biological pollutants. These contaminants hamstring the production of microalgae biomass by debilitating the growth of cultures, crumble the quality of biomass and sometimes may crash the whole culture. The best utilization of the microalgae biomass at industrial level could be attained by avoiding various possible biological contaminations in mass cultivation system, understanding the contamination mechanisms, and the complex interactions of algae with other microorganisms. This review explores the various types of biological pollutants, their possible mode of infection along with mechanisms, different controlling methods to maintain desired microalgae culture.

Microalgae wastewater treatment has long been promoted as a sustainable method to handle the influx of human waste due to population growth. Initially, in the early 1900’s, microalgae was noted to increase wastewater treatment efficiency by aerating the water and consuming waste. By mid-century, wastewater grown microalgae was being investigated as a way to produce biomass for food, fuel, and other biomaterials. The space race in the 1960’s led to the use of microalgae in life support systems. Technological developments and political pressure in the 1970’s spurred studies of the impact of wastewater on the growth of phytoplankton in the oceans as well as methods to use microalgae wastewater treatment in aquaculture. Simultaneously, the oil crisis of that decade promoted research of alternative fuels, which included microalgae biofuels via the Aquatic Species Program. This program led to research into the use of wastewater as a feedstock for microalgae growth. By the later 2000’s, instability in the oil market caused another energy crisis which further prompted investment in microalgae biofuels, some of which involved combined wastewater treatment. Currently, microalgae wastewater treatment is being researched as a way to cut back on greenhouse gas emissions to curb global warming and produce sustainable biofuels.

Biodiesel, a potent replacement for petroleum diesel, is derived from fatty acids in biomass through transesterification, which is renewable, non-toxic, and biodegradable and is a powerful replacement for petroleum diesel. Lewis acid has been proven effective for esterification and transesterification. The Lewis base enhances the electrophilic and nucleophilic properties of the molecules that bind to it, leading to the remarkable versatility in the Lewis base catalytic reaction. Many studies have shown that Lewis acid/base catalyzed in-situ transesterification is a fast and environmentally friendly method for producing biodiesel. The utilization of Lewis acid-base sites to catalyze transesterification has been shown to enhance their efficiency and utilization of ac-id-base active sites. This review explores biodiesel production by different catalysts using Lewis acid-base sites, the conditions for catalytic transesterification, the effects of different reaction parameters on biodiesel production, and biodiesel production process.

Phosphorus (P) is an important and irreplaceable macronutrient. It is central to energy and information storage and exchange in living cell. P is an element with “broken geochemical cycle” since it lacks abundant volatile compounds capable of closing the P cycle. P fertilizers are critical for global food security, but the reserves of minable P are scarce and non-evenly distributed between countries of the world. Accordingly, the risks of global crisis due to limited access to P reserves is expected to be graver than those entailed by competition for fossil hydrocarbons. Paradoxically, despite the scarcity and value of P reserves, its usage is extremely inefficient: current waste rate reaches 80% giving rise to a plethora of unwanted consequences such as eutrophication leading to harmful algal blooms. Microalgal biotechnology comprise a promising solution to tackle this challenge. The proposed review briefly presents the relevant aspects of microalgal P metabolism such as cell P reserve composition and turnover, and the regulation of P uptake kinetics for maximization of P uptake efficiency with the focus on novel knowledge. Multifaceted role of polyPhosphates, the largest cell depot for P, is discussed with emphasis on the P toxicity mediated by short-chain polyPhosphates. Opportunities and hurdles of P bioremoval via P uptake from waste streams with microalgal cultures, either suspended or immobilized, is discussed along with the role of bacterial components of microalgal-bacterial consortia in these processes. Possible avenues of P-rich microalgal biomass such as biofertilizer production or extraction of valuable polyPhosphates and other bioproducts are considered. The review concludes with a comprehensive assessment of the current potential of microalgal biotechnology for ensuring the sustainable usage of phosphorus.

Hermetia illucens is a very promising insect due to its ability to convert low-value substrates in highly nutrient feed. Its feeding and nutrition are important issues. This work aimed to study the effect of different substrates composed of coffee silverskin, by-product of the roasting process, enriched with different inclusion of microalgae (5%, 10%, 20%, 25%), Schizochytrium limacinum and Isochrysis galbana, coupled with the assessment of environmental sustainability by LCA. In general, the inclusion of microalgae caused an increase in the growth performance of the larvae, although S. limacinum showed the best results. Higher prepupal weight were observed in larvae fed on 20% and 25% of S. limacinum, shorter development times in larvae fed on 25% of both S. limacinum and I. galbana and higher growth rate were observed in larvae fed on 25% of S. limacinum. Anyway, the inclusion of 10% of S. limacinum showed a small difference with the higher inclusions. Moreover, the 10% of S. limacinum achieved the best waste reduction index. Therefore, considering the greater inclusion of microalgae, the higher the environmental impact of larvae production, the addition of 10% of S. limacinum seems to be the best compromise for the larval rearing.

Carotenoids are essential pigments that play a vital role in the photosynthetic process of algae and are important for human health and nutrition. Despite their potential value, algal carotenoids are being neglected by biofuel industries. Recent research is aimed at producing microalgal lipids and carotenoids simultaneously under abiotic stresses. In this study, the effect of different abiotic stress factors such as Nitrogen (N), Potassium (K), Phosphorous (P), Sulphur (S), light intensity, and photoperiod on biomass, lipid, and carotenoids synthesis in Monoraphidium sp. (MP) were explored utilizing a statistical method. In addition, 2, 7-dichlorofluorescein diacetate (DCF-DA) mediated spectrofluorimetry was employed to detect the ele-vation in ROS level. The results revealed that variations in nutrients and light con-ditions are the key factors in the up-regulation of biomolecules lipids and carote-noids in the algae. The carotenoids profiling was done by Ultra Performance Liquid Chromatography Quadrupole Time-of-Flight Mass Spectroscopy (UPLC-Q-ToF-MS). Among consisting carotenoids violaxanthin, astaxanthin, and beta-carotene were enhanced by 1.3 folds, 1.19 folds, 1.08 folds, while lutein was declined by 1.32 folds under stressed condition compared to control. The identified carotenoids are rec-ognized for their importance in the pharmaceutical and nutraceutical industries, highlighting the significant role of MP in these sectors.

In a thin-volume photobioreactor where a concentrated suspension of microalgae is circulated throughout the established spatial irradiance gradient, microalgal cells experience a time-variable irradiance. Deploying this feature is the most convenient way of obtaining the so-called “flashing light” effect, improving biomass production in high irradiance. This work investigates the light flashing features of sloping wavy photobioreactors, a recently proposed type, by introducing and validating a Computational Fluid Dynamics model. Two characteristic flow zones (straight top-bottom stream and local recirculation stream), both effective toward light flashing, have been found and characterised: a recirculation-induced frequency of 3.7 Hz and straight flow-induced frequency of 5.6 Hz were estimated. If the channel slope is increased, the recirculation area becomes less stable while the recirculation frequency is nearly constant with flow rate. The validated CFD model is a mighty tool that could be reliably used to further increase the flashing frequency by optimising the design, the dimensions, the installation and the operational parameters of the sloping wavy photobioreactor.

Llayta is a dietary supplement used by rural communities in Perú and northern Chile since pre-Columbian days. Llayta is the biomass of colonies of a Nostoc cyanobacterium grown in wetlands of the Andean highlands, harvested, sun-dried and sold as an ingredient for human consumption. The biomass has a substantial content of essential amino acids (58% of total amino acids) and polyunsaturated fatty acids (33% total fatty acids). This ancestral practice is being loss and the causes were investigated by an ethnographic approach to register the social representations of Llayta, to document how this Andean feeding practice is perceived and how much the community knows about Llayta. Only 37% of the participants (mostly adults) have had a direct experience with Llayta; other participants (mostly children) did not have any knowledge about it. These social responses reflect anthropological and cultural tensions associated to lack of knowledge on Andean algae, sites where to find Llayta, where it is commercialized, how it is cooked and on its nutritional benefits. The loss of this ancestral feeding practice, mostly on northern Chile, is probably associated to cultural changes, migration of the rural communities, and a very limited access to the available information. We propose that Llayta consumption can be revitalized by developing appropriate educational strategies and investigating potential new food derivatives based on the biomass from the isolated Llayta cyanobacterium.

Actuated carbon (AC) is utilized in various conditions of uses after its disclosure as a solid and dependable adsorbent. A review on AC is introduced along with returning to the wellsprings of AC age; strategies used to produce AC including pyrolysis enactment; actual actuation; synthetic initiation and steam pyrolysis. The significant variables influencing the AC creation, the potential uses of AC and their future possibilities are likewise examined. AC is applied in water, wastewater and leachate medicines in numerous nations, particularly to clean the shading, eliminate the smell and some substantial metals. Taking into account this, an exhaustive rundown of research on compound, physical and organic change strategies of initiated carbon relating to prevent of foreign substance expulsion from watery arrangements was aggregated and investigated. Additionally, the examination of the actual blending strategy and the impregnation technique in enactment with antacid metals shows that the actuated carbon got through actual blending had a higher porosity than the initiated carbon created by the impregnation technique. The uses of initiated carbon items were quickly surveyed.

Since the Industrial Revolution, nearly 700 GtC of carbon have been emitted into the atmosphere as CO2 derived from human activities, of which 292 GtC remain uncontrolled. Furthermore, the emission rate is increasing yearly, with the latest value (2022) of 11 GtC. By the end of this century, the atmospheric CO2 concentration is predicted to surpass 700 ppm. The effects of this sudden carbon release on the worldwide biogeochemical cycles and balances are not yet fully understood, but it is undeniable that global warming and climate change are already a fact, with this gas playing a starring role. Governmental policies and international agreements on emission reduction need to produce results quickly enough, and the deadline to act is running out. Besides the agreements to reduce emissions, alternative strategies to reverse this trend must be sufficiently promoted. Biological CO2 capture is a speedy flow of the carbon cycle capable of capturing over 115 GtC annually through photosynthesis. An increase of 6.5% in this capture and the subsequent stabilization of produced biomass could counteract the current CO2 emission rate. In this overview, the artificial culture of phytoplankton is considered a potential alternative to conducting this large-scale capture. A production system model is suggested and the main technological and political challenges for using large areas as partially-natural photobioreactors are discussed. The global implementation of these large CO2 sinks and the associated infrastructure would stabilize the carbon cycle while it is developed as a new source of richness.

: Seaweeds are among the most important biomass feedstocks for the production of third generation biofuels. They are also efficient in carbon sequestration during growth, and produce a variety of high value chemicals. Given these characteristics together with the relatively high carbohydrate content, seaweeds have been discussed as an ideal means for CO2 capture and biofuel production. Though third generation biofuels have emerged as some of the best alternatives to fossil fuels, there is currently no large-scale production or mainstream use of such liquid fuels due to the many technical challenges and high production costs. The present study describes the concept of coastal marine biorefineries as the most cost-effective and sustainable approach for biofuel production from sea-weeds as well as atmospheric carbon capture and storage (CCS). The suggested refinery system makes use of marine resources, namely seawater, seaweed, and marine microorganisms. Firstly, extensive screening of the current literature was performed to determine which technologies would enable the emergence of such a novel biorefinery system and its merits over conventional refineries. Secondly, the study investigates various scenarios assessing the potential of seaweeds as a means of carbon sequestration. We demonstrate that the removal of 100 Gigatons of excess CO2 using seaweed farms can be achieved in around 4 months to less than 12 years depending on the area under cultivation and the seaweed species. The total bioethanol that could be generated from the harvested biomass is around 8 trillion litres. In addition, high-value chemicals (HVC) that could potentially be recovered from the process represent a considerable op-portunity with multi-billion-dollar commercial value. Overall, coastal marine biorefineries have strong potential for a sustainable green economy and rep-resent a rapid approach for climate change mitigation.

(1) Background: Truing to find a fast and representative method for the approximate calculation of the culture density and the cell content of useful pigments, the examination of the absorption spectra of cultures of the dinoflagellate Amphidinium carterae, the haptophyte Isochrysis galbana, the chlorophyte Nephroselmis sp. and the filamentous cyanobacterium Anabaena sp. were chosen, as representative species of different taxa. (2) Methods: The experimental cultures were made in small volumes with the discontinuous method, under specific conditions each one and during the culture the absorption spectra, the density of the culture and the concentration in the pigments chlorophyll, total carotenoids and phycocyanin was recorded. (3) Results: The algal density can be quite precisely predicted as the regression equation of the correlation of the OD value of 750 nm drawn from each absorption spectrum and the measured algal biomass was very strong. The same applies also for the relevant correlations between OD 750 nm and the recorded pigments. (4) Conclusions: Absorption spectra of microalgal cultures can be an easy, low cost and non-invasive method to get the necessary information for predicting the right time to collect an ideal combination of maximum biomass and useful pigments, provided that the interpretation of the spectra is done considering that they are usefully applicable for that purpose in a case sensitive manner in terms of species and prevailing conditions.

Green microalgae including those from the genus Lobosphaera are exploited in biotechnology to obtain valuable fatty acids e.g., arachidonic acid (C20:4, ARA) for the production of infant formulae, food and feed additives. In nature, microalgae frequently exist in naturally immobilized state (as biofilms) with limited cell division rate and increased stress resilience. In biotechnology, immobilization of microalgae on artificial cell carriers simplifies biomass harvesting, increases culture robustness and productivity. The choice of suitable cell carrier is central to biotechnology of immobilized culture. Cell carriers based on the natural amine-containing polymer chitosan and synthetic polyethylenimine (PEI) are promising candidates for immobilization of phototrophic microorganisms. This is the first report on the effects of immobilization on PEI and chitosan on the accumulation and composition of polyunsaturated fatty acids, including ARA, in Lobosphaera sp. IPPAS C-2047. The immobilization on PEI increased ARA percentage in the total tatty acids and ARA accumulation by 72% and 81%, compared with the suspended cells cultured respectively in complete or nitrogen-deprived medium 14 days. Immobilization of Lobosphaera sp. on the chitosan-based carrier declined ARA but increased oleic and α-linoleic acid percentages. Mechanisms of the effects of immobilization on fatty acid profiles of the microalgae are discussed.

After a 1.5 year screening survey in the lagoons of Western Greece in order to isolate and culture sturdy species of microalgae for aquaculture or other value added uses, as dictated primarily by a satisfactory potential for their mass-culture, five species emerged and their growth was monitored in laboratory conditions. Amphidinium carterae, Nephroselmis sp., Tetraselmis sp. (var. red pappas), Asteromonas gracilis and Dunaliella sp. were batch cultured using low (20 ppt), sea (40 ppt) and high salinity (50 or 60 or 100 ppt) and in combination with a low (2000 lux) and high (8000 lux) intensity of illumination. The results exhibited that all these species can be grown adequately in all salinities and with best growth in terms of maximum cell density, specific growth rate (SGR) and biomass yield (g dry weight/L) at high illumination (8000 lux). The five species examined exhibited different responses in the salinities used, Amphidinium clearly does best in 20 ppt far better than 40 ppt and even more than 50 ppt. Nephroselmis and Tetraselmis grow almost the same in 20 and 40 ppt and less well in 60 ppt. Asteromonas does best in 100 ppt although it can grow quite well in both 40 and 60 ppt. Dunaliella grows equally well in all salinities (20-40-60 ppt). Concerning productivity as maximum biomass yield at the end of the culture period, first rank is occupied by Nephroselmis with ~3.0 g d.w./L, followed by Tetraselmis (2.0 g/L), Dunaliella (1.58 g/L), Amphidinium (1.19 g/L) and Asteromonas (0.7 g/L) with all values recorded at high light (8000 lux).

Microalgal harvesting is one of the most challenging processes in the development of algal research and development. Several methods, such as centrifugation, flocculation, and filtration, are available at the laboratory scale. However, the requirement of expensive pieces of equipment and the possibility of biomass contamination are recurring gaps that hinder the development of microalgae I+D in different parts of the world. Recently, the electroflotation has been proved as a suitable method for the harvesting of different species of microalgae and cyanobacteria. To this day, there are no companies that sell laboratory-scale electroflotation equipment; this is mainly due to the gap in the knowledge on which factors (time, mixing rate, number of electrodes, and others) will affect the efficiency of concentration without reducing the biomass quality. This paper aims to build an innovative low-cost electroflotation system under 300 USD with cheap and resistant materials. To achieve our goal, we test the interaction of three variables (time, mixing rate, and amount of electrodes) were evaluated. Results showed that an efficiency closer to 100% could be achieved under 20 minutes using >10 electrodes and 150 rpm. We hope this innovative approach can be used by different researchers to improve our knowledge of the concentration and harvesting of algae and cyanobacteria.

The purpose of this work is to define optimal growth conditions for batch culture of the cyanobacterium Arthrospira maxima and the microalgae Chlorella vulgaris, Isochrysis galbana and Nannochloropsis gaditana. Thus, we study the effect of three variables on algae growth: i.e., inoculum:culture medium ratio, light:darkness photoperiod and type of culture medium, including both synthetic media and wastewaters. The results showed that the initial inoculum volume did not affect the amount of biomass at the end of the growth (14 days), whereas an excess (18 h) or defect (6 h) in the number of hours of light is determinant for its development. The contribution of nutrients from different culture media modified the growth of the different species. A. maxima was favoured in seawater enriched with Guillard's F/2 as well as C. vulgaris and N. gaditana but in fresh water medium. I. galbana had the greatest growth in the marine environment enriched with Walne’s media. Nitrate was the limiting growth reagent at the end of the exponential phase of growth for C. vulgaris and N. gaditana, while iron was for A. maxima and I. galbana. All species demonstrated their capability to grow in effluents from a wastewater treatment plant and they efficiently consume nitrogen, especially the three microalgae species.

A hydrothermal pretreatment of the microalga Nannochloropsis gaditana at mild temperatures has been studied in order to reduce N and O content in the biocrude obtained by hydrothermal liquefaction (HTL). The work is focused on the evaluation of temperature, reactor loading and time (factors) to maximize the yield of the pretreated biomass and the heteroatom contents transferred from the microalga biomass to the aqueous phase (responses). The study followed the factorial design and response surface methodology. An equation for every response has been obtained, which leads to the accurate calculation of the operating conditions required to obtain a given value of these responses. Temperature and time are critical factors with a negative effect on the pretreated biomass yield, but a positive one on the N and O recovery in the aqueous phase. The slurry concentration has to be low to increase heteroatom recovery and high to maximize the pretreated microalga yields

Activated carbon (AC) is an effective adsorbent for creatinine removal in hemoperfusion. However, the hemocompatibility and adsorption capacity of AC was required to be improved furthermore. Heparin, a widely used anticoagulant biomacromolecule, could improve the hemocompatibility of the absorbents in different ways based on its molecular weight. Thus, it was necessary to study the surface modification with unfractionated heparin (UFH) or low molecular weight heparin (LMWH) on improvement of hemocompatibility and adsorption. In this study, UFH and LMWH were respectively grafted on AC through polyethyleneimine as an intermediate layer. The modification of AC about morphology, mechanical strength and pore structure was characterized by XPS, SEM, TA and BET. It was found that compared with AC, the morphology and mechanical strength AC-UFH and AC-LMWH could be well maintained, but the BET surface was decreased due to the grafting of macromolecules. Furthermore, AC-UFH and AC-LMWH showed the better hemocompatibility on protein adsorption, APTT and platelet activation compared with AC, in which AC-LMWH had lower fibrinogen adsorption and longer APTT than AC-UFH. Besides, it was found that AC, AC-UFH and AC-LMWH had no significant effect on blood cell composition. Finally, the adsorption capacity of adsorbents for creatinine was evaluated. Although there was no significant difference between AC-UFH and AC-LMWH, it was found that heparin could be interacted with creatinine to enhance the adsorption capacity when compared with AC-PEI. This study deepened the understanding of anticoagulation of heparinized surface and provided a theoretical basis for adsorbents in hemoperfusion.

This article presents the copper ions adsorption process using an activated carbon from winemaking wastes. The pH, temperature, activated carbon amount and initial copper concentration were varied based on a full factorial 2^k experimental design. Kinetic and thermodynamic studies were also carried out. The adsorption kinetics was found follow a pseudo-second-order model. The adsorption data fit better to the Langmuir isotherm. The ANOVA demonstrated that both pH of the solution and activated carbon dosage had the greatest influence on copper adsorption. The activation energy was -32 kJ·mol^-1 suggesting that the copper adsorption is a physic-sorption process. The best fit to a linear correlation was the moving boundary equation that controls the kinetics for the adsorption copper ions onto the activated carbon. The X-ray photoelectron spectroscopy (XPS) results reveal the existence of different copper species (Cu²⁺, Cu⁺ and or Cu⁰) on the surface of the carbonaceous adsorbent after the adsorption, which could suggest a simultaneous reduction process.

Background: We previously reported that human keratinocytes express protease-activated receptor (PAR)-2 and play an important role in activated protein C (APC)-induced cutaneous wound healing. This study investigated the involvement of PAR-2 in the production of gelatinolytic matrix metalloproteinases (MMP)-2 and -9 by APC during cutaneous wound healing. Methods: Full-thickness excisional wounds were made on the dorsum of male C57BL/6 mice. Wounds were treated with APC on days 1, 2, and 3 post-wounding. Cultured neonatal foreskin keratinocytes were treated with APC with or without intact PAR-2 signalling to examine the effects on MMP-2 and MMP-9 production. Murine dermal fibroblasts from PAR2 knock-out (KO) mice were also assessed. MMP-2 and -9 were measured by gelatin zymography, fluorometric assay, and immunohistochemistry. Results: APC accelerated wound healing in WT mice, but had negligible effect in PAR-2 KO mice. APC stimulated murine cutaneous wound healing was associated with differential 0temporal production of MMP-2 and MMP-9, with the latter peaking on Day 1 and the former on Day 6. In-hibition of PAR-2 in human keratinocytes reduced APC-induced MMP-2 activity 25~50, but had little effect on MMP-9. Similarly, APC-induced MMP-2 activation was reduced by 40% in cultured dermal fibroblasts derived from PAR-2 KO mice. Conclusion: This study shows for the first time that PAR-2 is essential for APC-induced MMP-2 production. Considering the important role of MMP-2 in wound healing, this work helps explain the underlying mechanisms of action of APC to promote wound healing through PAR2.

Microalgae are photosynthetic microorganism able to receive light from sunlight and external light sources for their growth. Despite the simplicity of cultivation and their widespread presence, the growth of microalgae is affected by several factors, light intensity being a crucial one as it is linked to external environmental conditions. On the other hand, microalgae cultivation in wastewater with high nitrogen content has become a promising alternative as a low cost nutrients substrate method. However, effluents may contain many compounds, making therefore difficult the assessment of light intensity on cells growth profile and especially on nutrients assimilation rate. The aim of this study was the examination of the effect of intensity of light source on the growth and nutrient uptake rates by a freshwater microalgae, Chlorella sorokiniana in the effluent from an anaerobic digestion plant, with nitrogen content reaching up to 5 g/L. Microalgae were cultivated using three light intensities (1,500, 5,000 and 12,000 lx) in 10% digestate mixtures in water. Samples were collected and analyzed for the presence of microalgae cells, while aqueous phase samples were subjected to the analysis of nitrogen and phosphorous content. Biomass productivity followed the light intensity pattern: the highest the light the highest the cells growth. A similar pattern was observed in the reduction rate of nitrogen and phosphorous concentrations; however, nutrients reduction rate per gram of microalgae were mainly associated to biomass growth rate, indicating that the effect of light intensity was significant for biomass growth, without however changing the main nutrients assimilation pathway. In addition, results indicated that under high light intensity, microalgae might change their metabolism towards formation of lipids against nitrogenous compounds.

In our previous study, we demonstrated that the microalgae Phaeodactylum tricornutum can bioaccumulate bisphenol A analogues. Since this microalgae species is part of the diet of marine filter-feeding organisms, such as bivalves, in this study we tested the hypothesis that a diet based on contaminated microalgae can exert negative effects on the clam Ruditapes philippinarum. Microalgae were exposed for 7 days to 300 ng/L of bisphenol AF, bisphenol F, and bisphenol S, alone or as a mixture, to allow bioaccumulation. Microalgae were then supplied as food to bivalves. After 7 and 14 days of diet, the effects of contaminated microalgae were evaluated on a battery of biomarkers measured in haemolymph/haemocyte, gills and digestive gland of clams. In addition, bioaccumulation of the three bisphenols was investigated in clams by UHPLC-HRMS. Results obtained demonstrated that total haemocyte count, and haemocyte proliferation were affected in clams fed with contaminated microalgae. The activity of some immune-related enzymes was also influenced. Significant alterations in antioxidant enzyme activities and oxidative damage to proteins and lipids were recorded in both gills and digestive gland from clams fed with contaminated microalgae. Alterations in epigenetic-involved enzyme activity were also found. No bioaccumulation of BPA analogues was detected in clam soft tissues. Overall, this study demonstrated that a diet of BPA analogues-contaminated microalgae can induce significant alterations of some important biological responses of R. philippinarum. To our knowledge this is the first study demonstrating the effects of ingestion of BPA analogues-contaminated microalgae in the clam R. philippinarum, suggesting a potential ecotoxicological risk for the marine food chain, at least at the first levels.

Four strains of green microalgae (Scenedesmus acutus, Scenedesmus vacuolatus, Chlorella sorokiniana and Chlamydomonas reinhardtii) were compared for growth and pigment composition under photoautotrophic or heterotrophic conditions. Batch growth experiments were performed in multicultivators with online monitoring of optical density. For photoautotrophic growth, light-limited (CO2-sufficient) growth was analysed under different light intensities during exponential and deceleration growth phases. The specific growth rate, mesured during exponential phase, and the maximal biomass productivity, measured during deceleration phase, were not related to each other when different light intensities and different species were considered. This indicates species-dependent photoacclimation effects during cultivation time, which was confirmed by light-dependent changes in pigment contents and compositions when exponential and deceleration phases were compared. Except for C. reinhardtii, that does not grow on glucose, heterotrophic growth was promoted to similar extents by acetate or by glucose, however these two substrates led to different pigment compositions. Weak light increased pigment contents during heterotrophy in the four species, but was efficient in promoting growth only in S. acutus. C. sorokiniana and S. vacuolatus exhibited the best potential for heterotrophic biomass productivities both on glucose and acetate, with carotenoid (lutein) content being the highest in the former.

Piggery wastewater (PWW) is characterized by its high concentrations of organic matter and ammonium, and by their odour nuisance. Traditionally, PWW has been treated in open anaerobic lagoons, anaerobic digesters and activated sludge systems, which exhibit high greenhouse gas emissions, a limited nutrients removal and a high energy consumption, respectively. Photosyn-thetic microorganisms can support a sustainable PWW treatment in engineered photobioreactors at low operating costs and with an efficient recovery of carbon, nitrogen and phosphorous. These microorganisms are capable of absorbing solar irradiation through the photosynthesis process to obtain energy, which is used for their growth and associated carbon and nutrients assimilation. Purple phototrophic bacteria (PPB) represent the photosynthetic microorganisms with the most versatile metabolism in nature, while microalgae are the most studied photosynthetic microor-ganisms in recent years. This review describes the fundamentals, symmetry and asymmetry of PWW treatment using photosynthetic microorganisms such as PPB and microalgae. The main photobioreactor configurations along with the potential of PPB and microalgae biomass valori-zation strategies are also discussed.

Biotechnological application of the green microalga Chlamydomonas reinhardtii hinges on the availability of selectable markers for effective expression of multiple transgenes. However, biological safety concerns limit the establishment of new antibiotic resistance genes and until today, only few auxotrophic markers exist for C. reinhardtii. The recent improvements in gene editing via CRISPR/Cas9 allows directed exploration of new endogenous selectable markers. Since editing frequencies with CRISPR/Cas9 techniques are often low, the Cas9-sgRNA ribonucleoprotein (RNP) delivery protocol was strategically optimized by applying nitrogen starvation to the pre-culture, increasing editing frequencies from 10% to 66% after pre-selection. Probing the essential polyamine biosynthesis pathway, the spermidine synthase gene (SPD1) is shown to be a potent selectable marker with versatile biotechnological applicability. Very low levels of spermidine (0.75 mg/L) were required to maintain normal mixotrophic and phototrophic growth in newly designed spermidine auxotrophic strains. Complementation of these strains with a synthetic SPD1 gene was achieved when the mature protein was targeted to either the cytosol or the chloroplast. This work highlights the potential of new selectable markers for biotechnology as well as basic research and proposes an effective pipeline for the identification of new auxotrophies in C. reinhardtii.

The Mediterranean diet has among its cornerstones the use of olive oil for its nutraceutical and organoleptic properties. Despite the numerous merits, olive-oil mill wastewater (OMWW), which is generated by the olive-oil extraction process, is one of the most serious environmental pollutants in the Mediterranean countries. The polluting potential of OMWW is due to its high content of tannins, polyphenols, polyalcohols, pectins and lipids. In this experiment, we tested the ability of five microalgae of the Chlorella group (SEC_LI_ChL_1, CL-Sc, CL-Ch, FB and Idr) in lowering the percentage of total phenolic compounds in vegetation water. In order to close the recovery cycle of a fortified citrus olive oils previously developed, we tested the vegetation wa-ter obtained with three different extraction processes (conventional, lemon and orange peels) at three concentrations each (10%, 25% and 50%). Results showed that strains Idr, FB and CL-Sc from the Lake Massaciuccoli can tolerate vegetation water from conventional and lemon peels extraction up to 25%; these strains can also reduce the phenolic compounds within the tests. The results demonstrate that the application of microalgae for OMWW treatment represent an inter-esting opportunity, and an eco-friendly low-cost solution to be developed within the companies as a full-scale approach.

Quorum sensing (QS) describes a process by which bacteria can sense the local cell density of their own species, thus enabling them to coordinate gene expression and physiological processes on a community-wide scale. Small molecules called autoinducers or QS signals, which act as intraspecies signals, mediate quorum sensing. As our knowledge of QS has progressed, so too has our understanding of the structural diversity of QS signals, along with the diversity of bacteria conducting QS and the range of ecosystems in which QS takes place. It is now also clear that QS signals are more than just intraspecies signals. QS signals mediate interactions between species of prokaryotes, and between prokaryotes and eukaryotes. In recent years, our understanding of QS signals as mediators of algae–bacteria interactions has advanced such that we are beginning to develop a mechanistic understanding of their effects. This review will summarize the recent efforts to understand how different classes of QS signals contribute to the interactions between planktonic microalgae and bacteria in our oceans, primarily N-acyl-homoserine lactones, their degradation products tetramic acids, and 2-alkyl-4-quinolones. In particular, this review will discuss the ways in which QS signals alter microalgae growth and metabolism, namely as direct effectors of photosynthesis, regulators of the cell cycle, and as modulators of other algicidal mechanisms. Furthermore, the contribution of QS signals to nutrient acquisition is discussed, and finally how microalgae can modulate these small molecules to dampen their effects.

Over the last decades, microalgal biomass has gained a significant role in the development of different high-end (nutraceuticals, colorants, food supplements, and pharmaceuticals) and low-end products (biodiesel, bioethanol, and biogas) due to rapid growth and high carbon fixing efficiency. Therefore, microalgae are considered a useful and sustainable resource to attain energy security while reducing our current reliance on fossil fuels. From the technologies available for obtaining biofuels using microalgae biomass, thermochemical processes (pyrolysis, HTL, gasification) have proven to be processed with higher viability, because they use all biomass. However, the biocrudes obtained from direct thermochemical conversion have substantial quantities of heteroatoms (oxygen, nitrogen, and sulfur) due to the complexity of the biomass's content of chemical components (lipids, carbohydrates, and proteins). As a solution, catalyst-based processes have emerged as a sustainable solution for the increase in biocrude production. This paper's objective is to present a comprehensive review of recent developments on catalyst mediated conversion of algal biomass. Special attention will be given to operating conditions, strains evaluated, and challenges for the optimal yield of algal-based biofuels through pyrolysis and HTL.

Modern day civilization is dependent on energy generation by fossil fuels. But the major drawback of using fossil fuels is environmental pollution. Microalgae are potential candidate for production of various products of interest, such as proteins, mini food, pigments and triglycerides that can be converted into biofuels. Lignocellulosic feedstocks are the most abundantly available raw material of plants that can serve as a promising feedstock for cultivating bacteria, fungi, yeasts and microalgae to produce biofuels and other value-added products. Owing to the abundant availability of these low/no cost substrates, can be utilized as feedstocks for cultivating microalgae to generate biogas/biodiesel. Likewise, there is much room to exploit defatted algal biomass to be used as animal/fish feed and oil producing/accumulating genes knowledge in future to produce high and good quality biodiesel and biogas.

Nanoparticles (NPs) have various applications in medicine, cosmetics, optics, catalysis, environmental purification, and other areas nowadays. With an increasing annual production of NPs, the risks of their harmful influence to the environment and human health is rising. Currently, our knowledge about the mechanisms of interaction between NPs and living organisms is limited. Additionally, poor understanding of how physical and chemical characteristic and different conditions influence the toxicity of NPs restrict our attempts to develop the standards and regulations which might allow us to maintain the safe living conditions. The marine species and their habitat environment are under continuous stress due to anthropogenic activities which result in the appearance of NPs in the aquatic environment. Our study aimed to evaluate and compare biochemical effects caused by the influence of different types of carbon nanotubes, carbon nanofibers, and silica nanotubes on four marine microalgae species. We have evaluated the changes in growth-rate, esterase activity, membrane polarization, and size changes of microalgae cells using flow cytometry method. Our results demonstrated that toxic effects caused by the carbon nanotubes strongly correlated with the content of heavy metal impurities in the NPs. More hydrophobic carbon NPs with less ordered structure had a higher impact on the red microalgae P. purpureum because of higher adherence between the particles and mucous covering of the algae; silica NPs caused significant inhibition of microalgae growth-rate predominantly produced by mechanical influence.

The escalating global demand for clean water has propelled research into sustainable and cost-effective purification methods. Activated carbon (AC) derived from biowaste materials presents an environmentally friendly and economically viable solution for water treatment. This review article provides an extensive overview of the synthesis techniques, characterization methods, and applications of biowaste activated carbon (BAC) for water purification. It discusses the diverse sources of biowaste, such as agricultural residues, food waste, and biomass, and explores various activation methods including physical, chemical, and biological processes. Furthermore, the article examines the adsorption mechanisms, performance factors, regeneration strategies, and emerging trends in BAC synthesis and application. Insights from this review can guide future research endeavors and facilitate the development of sustainable water purification technologies.

Polymers' controlled pyrolysis is an economical and environmentally friendly solution to prepare activated carbon. However, due to the experimental difficulty in measuring the dependence between tissues and pyrolysis parameters at high temperatures, the unknown pyrolysis mechanism hinders access to the target products with desirable morphologies and performances. In this study, we investigate the pyrolysis process of polystyrene under different heating rates and temperatures employing reactive molecular dynamics (ReaxFF-MD) simulations. A clear profile of the generation of pyrolysis products determined by the temperature and heating rate is constructed. It is found that the heating rate affects the type and amount of pyrolysis intermediates and their timing, and low-rate heating helps yield more diverse pyrolysis intermediates. While the temperature affects the pyrolytic tissues of the final equilibrium products, either too low or too high a target temperature is detrimental to generating large areas of graphitized tissue. The established theoretical evolution process matches experiments well, thus contributing to preparing target activated carbons by referring to the regulatory mechanism of pyrolytic tissues.

Along with the rapid development of technology and industry, the need for energy storage has become fundamental. One promising energy storage devices is the supercapacitor. Several type supercapacitors are available, one of which is the electrical double-layer capacitor made from carbon graphite and multiwalled carbon nanotubes (MWCNTs). In this study, we combined these two materials into a working electrode in a three-electrode system. In the morphological analysis using scanning electron microscope, transmission electron microscope, and X-ray diffraction, the two materials were found to have formed a composite on the surface. In the electrochemical analysis, two types of testing were conducted using cyclic voltammetry and electrochemical impedance spectroscopy. Electrochemical analysis was carried out on five electrolyte concentrations of Na2SO4 from 1 to 6 M. The capacitance produced at concentrations of 1, 2, 3, 4, and 5 M were 34.395, 35.808, 46.284, 49.502, and 76.815 F/g, respectively. At an electrolyte concentration of 5 M Na2SO4, an energy density of 27.312 Wh/Kg and a power density of 343.786 W/Kg were produced. Meanwhile on concentration of 6 M, the surface of the electrode was damaged.

This paper describes the physico-chemical study of the adsorption of dysprosium (Dy³⁺) in aqueous solution onto two types of activated carbons synthesized from spent coffee ground. KOH activated carbon is a microporous material with a specific BET surface area of 2330 m²·g^-1 and pores with a diameter of 3.2 nm. Carbon activated with water vapor and N₂ is a solid mesoporous, with pores of 5.7 nm in diameter and a specific surface of 982 m²·g^-1. A significant dependence of the adsorption capacity on the solution pH was found, while it does not depend significantly neither on the dysprosium concentration nor on the temperature. A maximum adsorption capacity of 31.26 mg·g^-1 and 33.52 mg·g^-1 for the chemically and physically activated carbons, respectively, were found. In both cases, the results obtained from adsorption isotherms and kinetic study were better fit to a Langmuir model and a pseudo-second-order kinetics. In addition, thermodynamic results indicate that dysprosium adsorption onto both activated carbons is an exothermic, spontaneous and favorable process.

This study surveyed the variation in Perfluorinated Compounds (PFCs) concentration entering urban wastewater treatment plants and proposed an optimal PFCS treatment method. The PFCS concentration in influent was shown to be affected by the types of industries and operating rate. The concentration of PFCs in the wastewater treatment effluent was slightly lower than that of influent. Thus, PFCs were considered to have barely been removed by the existing biological treatments. The pilot test result showed that about 10% of PFCs were removed by coagulation and precipitation, and the ozone and chlorine test also showed that few PFCs were removed regardless of the amount of injection. The activated carbon adsorption test showed that the removal was significantly increased by the empty bed contact time, with about a 60% removal in five minutes and over a 90% removal in 15 minutes. Therefore it is determined that a more stable and higher PFCs removal would result from the continuous oxidation processes such as ozone and adsorption processes such as activated carbon rather than a single biological treatment.

This review analyzes the synthesis and characterization of biomass-derived carbons for adsorption of emerging contaminants from water. The study begins with the definition and different types of emerging contaminants more often founded in water streams and the different technologies available for their removal including adsorption. It also describes the biomass sources that could be used for the synthesis of biochars and activated carbons. The characterization of the adsorbents and the different approaches that could be employed for the study of the adsorption processes are also detailed. Finally, the work reviews in detail some studies of the literature focused on the adsorption of emerging contaminants on biochars and activated carbons synthesized from biomass precursors.

The aim of the present study is to provide new insights into the CO2 and CH4 adsorption using a set of biomass-based activated carbons obtained by physical and chemical activation of olive-stones. The adsorption behavior is analyzed by means of pure gas adsorption isotherms up to 3.2 MPa at two temperatures (303.15 and 323.15 K).The influence of the activation method on the adsorption uptake is studied in terms of both textural properties and surface chemistry. For three activated carbons the CO2 adsorption was more important than that of CH4. The chemically activation resulted in higher BET surface area and micropore volume that lead to higher adsorption for both CO2 and CH4. For methane the presence of mesopores seems to facilitate the access of the gas molecules into the micropores while for carbon dioxide, the presence of oxygen groups enhanced the adsorption capacity.

This study aimed to determine a nutritionally adequate feeding protocol for Hippocampus hippocampus juveniles. In the experimental trial, seahorses were fed copepods from 0-7 days post-parturition (DPP) and, from 8-28 DPP, four dietary treatments: (copepods (control diet), microalgae-enriched Artemia with a DHA/EPA ratio of 2:1, microalgae-enriched Artemia with a DHA/EPA ratio of 2:1 along with 5% copepods, and with 10% copepods) were tested. Results showed that juvenile seahorses fed on copepods attained a significantly higher (P<0.05) growth performance (5.1 mg d-1) than fish-fed diets with 5% and 10% copepod inclusion, (3.09 and 3.07 mg d-1, respectively), and fish-fed enriched Artemia (1.83 mg d-1) which performed poorly. Data suggests that feeding copepods during the first 7 DPP promotes maturation of the digestive tract of juvenile seahorses, and the addition of a limited amount of copepods to the diet improves H. hippocampus juvenile growth performance when compared to the use of Artemia as a single diet due to the improvement of the essential fatty acid profile in the diets.

In order to ensure food security worldwide in the face of current climatic changes, a higher quality and quantity of crops is necessary to sustain the growing human population. By developing a sustainable circular economy and biorefinery approaches, we can move from a petroleum-based to a bio-based economy. Plant biostimulants have long been considered an important source of plant growth stimulants in agronomy and agro-industries with both macroalgae (seaweeds) and microalgae (microalgae). There has been extensive exploration of macroalgae biostimulants. A lack of research and high production costs have constrained the commercial implementation of microalgal biostimulants, despite their positive impact on crop growth, development and yields. The current knowledge on potential biostimulatory compounds, key sources and their quantitative information from algae is summarized in the present review. Our goal is to provide a brief overview of the potential for microalgal biostimulants to improve crop production and quality. A number of key aspects are discussed, including the biostimulant effects caused by microalgae extracts, as well as the feasibility and potential for cocultures and coapplication with other biostimulants and biofertilizers. This article also discusses the current knowledge, recent developments and achievements in extraction techniques, types of applications, timings of applications. Ultimately, this review highlights the potential for microalgal biostimulants for sustainable agricultural practices, the algal biochemical components contributing to these traits, and finally bottlenecks and involved prospects in commercializing microalgal biostimulants.

A prominent feature of stress-tolerant microalgae is their versatile metabolism allowing then to synthesize a broad spectrum of molecules with beneficial effects on many aspects of human body functioning. This is in line with the current understanding that many stress-induced deleterious processes in the human body and in photosynthetic cell are mediated by the same mechanisms such as free-radical attacks and lipid peroxidation. These related risks are kept at bay by optical screening of harmful UV, enzymatic ROS elimination systems, and potent low-molecular antioxidants. Microalgae synthesize a broad spectrum of compounds exerting antioxidant and/or UV-absorbing properties. In microalgae, they increase stress-resilience of these organisms. In human body, they exhibit photoprotective, antiaging, and sunscreen activities. Therefore, these algal metabolites were recognized as promising ingredients for innovative cosmetics and cosmeceutical formulations. Ever increasing effort is being invested into the search for new natural biologically active substances from microalgae. This trend is also fueled by the growing demand for natural raw materials for food, pharmaceuticals and cosmetology associated with the global transition to a "greener" lifestyle. Here, we review the currently accumulated knowledge about the main groups of cosmeceutical compounds from microalgae.

Repeated cocaine produces an enhanced locomotor response (sensitization) paralleled by biological adaptations in the brain. Previous studies demonstrated region-specific responsiv-ity of adenosine monophosphate-activated protein kinase (AMPK) to repeated cocaine. AMPK maintains cellular energy homeostasis at the organismal and cellular level. Here we first quanti-fied changes in phosphorylated (active) and total AMPK in the cytosol and synaptosome of the medial prefrontal cortex, nucleus accumbens, and dorsal striatum following acute or sensitizing cocaine injections. Rats were given cocaine (15 mg/kg, IP) or saline for six days with a challenge injection on day seven resulting in four groups: saline-saline, saline-cocaine, cocaine-saline, and cocaine-cocaine. Brain region and cellular compartment selective changes in AMPK and pAMPK were found with some differences associated with acute withdrawal versus ongoing cocaine treatment. Other rats were pretreated with the indirect AMPK activator metformin. Metformin potentiated the locomotor activating effects of acute cocaine but blocked the development of sensi-tization. Sex differences largely obscured protein level treatment group effects, although pAMPK in the NAc shell cytosol was surprisingly reduced by metformin in rats receiving repeated co-caine. These data inform our understanding of AMPK activation dynamics in subcellular com-partments and provide additional support for repurposing metformin for cocaine use disorder.

Water pollution, driven largely by the discharge of organic dyes from various industrial processes, presents a grave environmental threat. This study delves into the promise of an innovative adsorptive composite material composed of chitosan and activated charcoal, offering a sustainable and efficient solution for removing methylene blue (MB) dye from water sources. Our comprehensive investigation encompasses the synthesis, characterization, and adsorption capabilities of this composite material, revealing its remarkable physicochemical attributes and its substantial capacity to adsorb MB dye. These findings establish it as a compelling candidate for water treatment applications. The assessment of adsorbent dosage shows a direct correlation between higher dosages and enhanced MB dye removal, with an optimal dosage determined at 0.4 g/25 mL. Furthermore, pH-dependent studies demonstrate exceptional performance at lower pH levels, achieving an impressive 95% removal rate at pH 3 after 240 minutes of contact time. The composite exhibits consistent high removal percentages across a wide range of MB dye concentrations, showcasing its adaptability. In terms of reaction time, the composite achieves peak adsorption capacity within the initial 360 minutes and maintains a stable equilibrium, sustaining an impressive 99% removal efficiency thereafter. This study underscores the eco-friendliness and cost-effectiveness of the composite material, emphasizing its potential to address water pollution challenges and promote sustainable water resource management. Overall, this research yields valuable insights into a practical approach for mitigating the adverse impact of organic dyes on aquatic ecosystems and public health.

Natural laterite fixed-bed column intercalated with activated carbon prepared from Balanites ae-gyptiaca (BA-AC) was used for As(III) removal from an aqueous solution. Investigations were carried out to solve the problem of column clogging which appears during water percolation through the column. Experimental tests were conducted to evaluate the hydraulic conductivity and the effects of various parameters such as grain size, bed height, and initial As(III) concentra-tion. The breakthrough increased from 15 to 85 h with the increase of the bed height from 20 to 40 cm, and decreased from 247 to 32 h with the increase of initial As(III) concentration from 0.5 to 2 mg/L. The permeability data showed that the fixed-bed column filled with laterites layers intercalated with activated carbon performs much better than the non-intercalated adsorbent col-umn. The Bohart-Adams model showed that increasing the bed height induced a decrease in kAB and N0 values. The critical bed depths determined using the bed depth service time (BDST) mod-el for As(III) removal were 15.23 and 7.98 cm for 1 and 20% breakthrough, respectively. The re-sults showed that the new low-cost filtration system, based on laterite layers alternated with BA-AC layers, could be used for the treatment of arsenic-contaminated water.

This study presents a novel polyurethane-activated carbon composite (PACC) as an effective and sustainable adsorbent for treating lead-ion-contaminated waters. The PACC was characterized using SEM-EDX, FTIR, BET, XRD, and TGA to evaluate its physicochemical and thermal properties. Furthermore, the PACC was employed in an experimental column adsorption setup to investigate its adsorption performance and to develop a dynamic method suitable for industrial implementation. Parameters such as bed height (50, 100, 150 mm), flow rate (4, 6, 8 mL min-1), pH (2, 4, 6), and initial metal ion concentrations (10, 50, 100 mg L-1) were examined. The experimental data exhibited strong agreement with the Thomas and Yoon-Nelson models (R2 ≥ 0.96), indicating efficient adsorption mechanisms. Remarkably, the depleted adsorbent has the potential for facile regeneration without substantial loss in capacity. The PACC demonstrated excellent adsorption performance for lead ions in aqueous solutions in a fixed-bed column system. Thus, the novel PACC material holds potential for scalable application in industrial settings to address water pollution challenges, especially in regions with uncontrolled effluent discharge.

An attempt to investigate the effect of binary composite activators on the microstructure of fly ash-based geopolymers is conducted through the comparison of 24 experiments, which consisted of Na2SiO3•9H2O, Na2CO3, K2CO3, NaOH, and KOH through a facile preparation technique. The results show that the activator of Na2SiO3•9H2O+KOH presents the highest mechanical strength, due to the synergy activation between the inherent ≡Si-O-Si≡ chains derived from Na2SiO3 and K+’s catalysis. It reveals that the K+ plays a crucial role in Na2SiO3-activated fly ash geopolymer, which is the rate-determining step of the enhanced crosslinking and propagation of N-(C)-A-S-H chains, leading to an increase in weight loss temperatures of specimens from TG/DTG results. Furthermore, the adding silica fume facilitates as-formed amorphous silicates, which also could fill into the pores of N-(C)-A-S-H amorphous gels and present a uniform and compact morphology, leading to an increase in the pore volume of the pore diameter less than 100 nm. It explores an efficient and cost-effective preparation of fly ash-based geopolymer for developing solid-waste recycling techniques.

This paper describes the influence of the regeneration treatments on 4-chloro-2-methyl-phenoxyacetic acid (MCPA)-loaded activated carbons (ACs) on adsorption-desorption cycles with two commercial ACs, Merck and Norit 1240 X ( Norit 1240 X was used in a granular and powder form). The ACs were saturated with MCPA and then submitted to four regeneration cycles, by washing with ethanol, NaOH solutions and washed with NaOH solutions followed by a thermal treatment. The ACs regenerated with ethanol showed a better performance concerning the successive adsorption-desorption cycles. On the first cycle, the MCPA desorbed, from washing with ethanol, from all ACs was higher than 99%. After a fourth adsorption-desorption cycle, washing regeneration combined with thermal treatment allowed excellent regeneration results. The amount of MCPA adsorbed on Norit 1240 X AC was higher than the amount adsorbed in the first cycle. MCPA adsorption kinetic data were analyzed by applying pseudo-first-order, pseudo-second-order, and Weber-Morris models. The pseudo-second-order fit better fit to the data and the Weber-Morris representation allows confirming that on Norit 1240 X, in a granular form, the pore diffusion was the limiting factor concerning the MCPA adsorption.

Common bean (Phaseolus vulgaris L.) is an important crop for food security and for national economics for several countries worlwide. One of the most important factors of risk in common bean production is the fungal disease anthracnose caused by Colletotrichum lindemuthianum, which in some cases, causes complete yield losses; this kind of plant disease is usually managed through the application of chemical products such as fungicides, that are commonly not accepted by society, this rejection is based on the relationship of pesticides with health damage and environmental contamination. In order to help in solving this drawbacks, the present work propose the use of Electrochemically Activated Salt Solutions(EASS) as a safer pathogen control agent in crops due to it have shown an elicitor and biostimulant effect on plants such as tobacco and apple. With this background, this manuscript presented in vitro results of the evaluation of the inhibitory effect for multiple bean pathogens and in vivo results of EASS in the common bean-Colletotrichum pathosystem by in vitro evaluations of the inhibitory effect for multiple bean pathogens and in vivo evaluation of the infection severity and defense activation such as secondary metabolites production and antioxidant activity. EASS presence in growth media had strong inhibitory effect, at beginning of experiment, for some of the evaluated fungi. EASS showed effect against the development of the disease when applied in specific doses to prevent distress in plants.

Steel slag is a co-product of the steelmaking industry, this material is rarely used as a binder due to its low cementitious properties. Thus, it´s believed that the alkaline activation of steel slag can enable its use as a cementitious material. This work has the objective of making a systematic bibliographic review on the theme "slag melt as a precursor in activated alkali binders". To this end, the ProKnow-C method was used for the selection and analysis of relevant research on the topic. The portfolio resulted in 71 texts, mostly journals paper. Bibliometrics showed that the country with the most publications is China and the journal with the most publications is Construction and Building Materials. The critical analysis concluded that the XRD, XRF, and compressive strength tests are the most used for the characterization of the material. It is possible to establish that there are some knowledge gaps on the subject, such as better mechanical characterization and greater production of works with dosing by the one-part method.

In recent years, several alternatives for improving the thermal comfort conditions inside buildings have been proposed. Among these alternatives, Thermally Activated Building Systems (TABS) have become of interest due to the benefits this technology brings to the building sector. The TABS are embedded in different building components and exchange heat with building envelope to improve the indoor air temperature. This review presents relevant results presented in the literature on the thermal behavior of TABS, the different types of TABS configurations, and the main parameters of TABS studied such as pipe separation, fluid inlet temperature, fluid velocity, and volumetric flow rate. The potential of TABS to improve thermal comfort conditions and provide energy savings is also discussed. Further, this study presents the different modes of application.

Cadmium (II) contamination in the environment is an emerging problem due to its acute toxicity and mobility, so it is very urgent to remove this species from industrial wastewater before it is discharged into the environment. Thus, a starch-based activated carbon (AC) with a specific surface area of 1600 m2g-1 is used as an adsorbent for the capturing of toxic Cadmium (II) ions from synthetic solution. The sorbent is characterized by BET, SEM, TEM, XRD, FT-IR, TGA, and zeta potential. The maximum uptake (284 mg g-1) of Cadmium (II) ion is obtained at pH 6. The thermodynamics parameters like ∆G, ∆H, ΔS are found to be -17.42 kJmol-1, 6.49 kJ mol-1, and 55.66 Jmol-1K-1 respectively, revealing that the adsorption mechanism is endothermic, spontaneous, and feasible. The experimental data follows the D-R and Langmuir models well. The mass transfer is controlled by pseudo 2nd order kinetics. Furthermore, the density functional theory simulations demonstrate that the activated carbon strongly interacted with the Cd (II) ion through its various active sites. The adsorption energy noted for all interactive sites is highly negative (-0.45 eV to -10.03 eV), which shows that the adsorption process is spontaneous and stable which is in agreement with the experimental thermodynamics analysis.

Antibiotics are among the most critical environmental pollutant drug groups. One of the methods used to remove this pollution is adsorption. In this study, activated carbon was produced from the pumpkin seed shell and then modified with KOH. This adsorbent obtained was used in the re-moval of ciprofloxacin from aqueous systems. Fourier Transform-Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), elemental, X-ray Photoelectron Spectroscopy (XPS), Brunauer-Emmett-Teller (BET) and Zeta analyzes were used for the characterization of the ad-sorbent. In particular, the surface area was found to be a very remarkable value of 2730 m2/g. The conditions of the adsorption experiments were optimized based on interaction time, adsorbent amount, pH and temperature. Over 99% success has been achieved in removal works carried out under the most optimized conditions. In addition, it was determined that the Langmuir isotherm is the most suitable model for the adsorption interaction.

Ionic liquids (ILs) have gained interest among researchers due to its tunable properties that can be used in wide applications. However, toxicity and bio-degradation studies of ILs proved that most of the aromatic ILs, such as imidazolium is highly toxic and non-biodegradable. Several advance oxidation processes (AOPs) have been investigated by researchers to evaluate the efficiency of the systems for the removal of ILs from wastewater. However, the issue on relative high cost and environmental concern has limited the application of these AOPs in industry. In this research, photocatalytic study using hybrid nano-materials was conducted to evaluate the efficiency of this system as an alternative AOP system for removal of ILs from wastewater. The synergistic effect of adsorption-photodegradation was introduced by depositing Fe-TiO₂ onto the functionalized activated carbon (AC). Nano-TiO₂ was synthesized using micromulsion method before modification with transition metal and deposited onto the oxidized AC. Photodegradation reaction of 1-butyl-3-methylimidazolium chloride [bmim]Cl was investigated under simulated visible light irradiation. It was observed that the overall efficiency of the system was increased with the increasing amount of Fe dopant. Investigation on the extrinsic factors such as solution pH, initial concentration of ILs and photocatalyst dosage showed to significantly affect the overall efficiency of the systems where the optimum condition for the system was observed at pH 10, with initial ILs at 1mM at 1 g/L of photocatalyst. The best performance photocatalyst was 0.2Fe-TiO₂/AC.

Microalgae cultivation for biotechnological purposes is an expanding field. Their cultivation is usually performed on a liquid culture medium and require the presence of an energy source. Culture media are water-salt solutions containing nitrogen, sulfur, phosphate sources, with trace of transition metals. Light source supplies energy through photosynthesis process, resulting in metabolic reactions and cell growth. Thanks to the huge number of existing species and their diversity, it is possible to exploit alternative water sources with chemical and physical properties far from the commonly used freshwater media. Among these, oilfield or formation waters (AFW) are saline wastewater produced during oil drilling. They represent over 95 % of the total fluids collected from gas and oil wells during fuel extraction. This study exploits the adaptation capability of a Galdieria sulphuraria strain in different salinity conditions to build up a more feasible microalgae-based platform. Batch cultivation of G. sulphuraria was evaluated in a range from 0 to 20 g/L NaCl in terms of growth rate, metabolite content, photophysiology, and intracellular redox state. Moreover, the same strain has been tested for artificial formation water growth in semicontinuous cultivation mode. In these condition, NaCl preadaptation effect has been assessed too. Results clearly demonstrate that biomass composition is influenced from medium salinity. Strains preadapted in 0 to 20 g/L range of NaCl salinity show almost same cell growth profile and a slightly different ratio between lipids, carbohydrates, and proteins. Pigments content and photophysiology point out that variations of osmotic pressure and ionic strength in medium affect Photosystem II (PSII). Regulation of light harvesting is necessary to trigger metabolism shift toward synthesis of metabolites required in the adaptation process.

Marine microalgae are a rich reservoir of natural compounds, including bioactives. Nonetheless, these organisms remain fairly unexplored despite their potential biotechnological applications. Culture collections with diverse taxonomic groups and lifestyles are a good source to unlock this potential and discover new molecules for multiple applications such as the treatment of human pathologies or the production of aquaculture species. In the present work extracts from 33 strains (including 20 dinoflagellates, 4 diatoms and 9 strains from other 7 algal classes), cultivated under identical conditions were examined for antiviral, antibacterial, anti-inflammatory and anti-cancer activities. Among these, antiviral and anti-inflammatory activities were detected in a few strains while antibacterial tests showed positive results in most assays. In turn, most trials did not show any anti-cancer activity. Wide differences were observed between species within the same class, in particular dinoflagellates which were better represented in this study. These preliminary findings pave the way for in-depth characterization of extracts with highest signals in each test, identification of compounds responsible of the biological activities found, and a further screening of the CCVIEO culture collection.

In recent times, there has been a revolutionary surge in antioxidant research, with a focus on harnessing microalgae to enhance wellness and extend human longevity. Microalgae, a diverse group of unicellular photosynthetic organisms, have emerged as promising sources of natural antioxidants due to their ability to synthesize various bioactive compounds, including carotenoids, polyphenols, and tocopherols. These antioxidants play a pivotal role in scavenging free radicals and reducing oxidative stress, known contributors to aging and chronic diseases. This review provides an overview of recent advancements in understanding microalgae's antioxidant potential, covering their biochemical composition, extraction techniques, and purification methods. Moreover, it delves into compelling in vitro and in vivo studies showcasing microalgae-derived antioxidants' protective effects against oxidative damage, inflammation, cardiovascular diseases, and neurodegenerative disorders. The sustainable cultivation of microalgae in controlled environments further supports the potential for large-scale production and commercialization of their antioxidant compounds. As microalgae continue to revolutionize antioxidant research, they hold immense promise in developing novel preventive and therapeutic strategies to promote human health and wellbeing.

Because of the near-term risk of extreme weather events and other adverse consequences from climate change, and, at least in the longer term, global fossil fuel depletion, there is world-wide interest in shifting to noncarbon energy sources, especially renewable energy (RE). Because of possible limitations on conventional renewable energy sources, researchers have looked for ways of overcoming these shortcomings by introducing radically new energy technologies. The largest RE source today is bioenergy, while solar energy and wind energy are regarded as having the largest technical potential. This paper reviews the literature on proposed new technologies for each of these three RE sources: microalgae for bioenergy, photolysis and airborne wind turbines. The main finding is that their proponents have underestimated the difficulties facing their introduction on a very large scale.

The halotolerant photoautotrophic marine microalga Dunaliella salina is one of the richest sources of natural carotenoids. Here we investigated the effects of high intensity blue, red and white light from light emitting diodes (LED) on the production of carotenoids by strains of D. salina under nutrient sufficiency and strict temperature control favouring growth. Growth in high intensity red light was associated with carotenoid accumulation and a high rate of oxygen uptake. On transfer to blue light, a massive drop in carotenoid content was recorded along with very high rates of photo-oxidation. In high intensity blue light, growth was maintained at the same rate as in red or white light, but without carotenoid accumulation; transfer to red light stimulated a small increase in carotenoid content. The data support chlorophyll absorption of red light photons to reduce plastoquinone in photosystem II, coupled to phytoene desaturation by plastoquinol:oxygen oxidoreductase, with oxygen as electron acceptor. Partitioning of electrons between photosynthesis and carotenoid biosynthesis would depend on both red photon flux intensity and phytoene synthase upregulation by the red light photoreceptor, phytochrome. Red light control of carotenoid biosynthesis and accumulation reduces the rate of formation of reactive oxygen species (ROS) as well as increases the pool size of anti-oxidant.

The optimal combination of five components to develop a concrete for high-temperature applications was studied through a response surface methodology known as mixture design of experiment. The selected components were water, an alkali-activated binder based on ferronickel slag activated with potassium silicate and potassium hydroxide, and three aggregate sizes corresponding to 0-4 mm, 4-8 mm, and 8-16 mm. Selected response parameters were slump and compressive strength before and after heat exposure. Six cubes of side 150 mm were cast for each concrete mix, three for ambient and three for residual (post-heat exposure) compressive strength. All 20 concrete mixes were exposed to a thermal load of 600 °C for two hours. The optimal concrete mix was adapted for large-scale applications, by increasing slump and replacing limestone with olivine aggregates for enhanced residual compressive strength. The adapted mix resulted in concrete with 76 MPa and 32 MPa compressive strength before and after high-temperature exposure. The CO2 emissions were found to be 77 % lower when compared to traditional OPC concrete.

Biochar is a porous material produced by pyrolisis of biomass and can be modified using metal oxide to improve its adsorption performance, especially toward organics substances. The activated biochar was synthesized from patchouli biomass to study effect of calcination temperature on both structural properties and paracetamol drug adsorption of the composite was studied. Some process routes were conducted, including the patchouli biomass pyrolysis using CoCl2 activator, the activated biochar impregnation using 0.1 M FeCl3 solutions, biochar-FeCl3 calcination at various temperatures (400, 600, 800 oC) in the almost closed porcelain crucible, product characterizations using X-ray diffraction and FTIR spectrometry, and paracetamol adsorption test at various concentrations (10, 20, 30, 40, and 50 ppm). The paracetamol concentrations were analyzed using UV-Vis spectrophotometry at 243 nm. The adsorption data was treated using Langmuir, Freundlich, and Dubinin-Radushkevich (DR) models. The product diffractograms indicated α-Fe2O3, γ-Fe2O3, FeFe2O4 beside the carbon turbostratic structure. The metal oxide peak heights increased by increasing of the temperature. FTIR spectra significantly started to change at 600 oC. Adsorption test of paracetamol gave the highest adsorption capacity of 56.37 mg/g at 800 oC (Langmuir model) with correlation coefficient of 0.964. The highest adsorption energy was achieved at 800 oC, i.e 530.33 J/mol (physical adsorption) with a dimensionless factor, the RL value of 0.86 (favorable adsorption), and the n constant of 1.58 (favorable adsorption).

Over the past decade, the production of biofuels from lignocellulosic biomass has steadily increased to offset the use of fuels from petroleum. To make biofuels cost-competitive, however, it is necessary to add value to the “ligno-” components (up to 30% by mass) of the biomass. The properties of lignin, in terms of molecular weight (MW), chemical functionality, and mineral impurities often vary from biomass source and biorefinery process, resulting in a challenging precursor for product development. Activated carbon (AC) is a feasible target for the lignin-rich byproduct streams because it can be made from nearly any biomass and it has a market capacity large enough to use much of the lignin generated from the biorefineries. However, it is not known how the variability in the lignin affects the key properties of AC, because until now, they could not be well controlled. In this work, various fractions of ultraclean (< 0.6 % ash) lignin are created with refined MW distributions using Aqueous Lignin Purification using Hot Agents (ALPHA) and used as precursors for AC. AC is synthesized via zinc chloride activation and characterized for pore structure and adsorption capacity. We show that AC surface area and the adsorption capacity increase when using lignin with increasing MW, and furthermore, that reducing the mineral content of lignin can significantly enhance the AC properties. The surface area of the AC from the highest MW lignin can reach ~1830 m2/g (absorption capacity). Furthermore, the single step activation carbonization using zinc chloride allows for minimal carbon burnoff (< 30%) capturing most of the lignin carbon compared to traditional burn off methods in biorefineries for heat generation.

The production of municipal solid waste incineration bottom ash (MSWIBA) is very massive and has the potential to replace cement despite the problems of complex composition, uneven particle size distribution, and low reactivity. This paper adopts sodium silicate activation of MSWIBA-slag to improve the reactivity to prepare composite cementitious materials. It explores the hydration performance study of the composite cementitious materials by isothermal calorimetric analysis, Fourier Transform Infrared (FTIR) spectroscopy, XRD physical diffraction analysis, and SEM/EDS tests. SEM/EDS tests will be used to explore the hydration properties of the composite gelling. The results showed that with the increase of MSWIBA doping, the porosity between the materials increased, the degree of Hydration decreased, and the compressive strength decreased with the rise of MSWIBA. When sodium silicate increased from 25% to 35%, too much alkaline material occurred over the alkaline effect, which inhibited the Hydration of the particles, and the degree of hydration reaction decreased, and the compressive strength decreased accordingly; the exothermic process of Hydration can be mainly divided into five stages, quartz and calcite did not participate in the hydration reaction completely, and sexual aluminum participated in the hydration reaction. The vibrational peaks of Si-O-Ti (T = Si and Al) were present in the material. The vibrational peaks of XRD, FTIR, and SEM-EDS all indicate the presence of silica-aluminate network structures in the hydration products, mainly N-A-S-H and C-A-S-H gels.

Continuous cropping of Platycodon produces problems that significantly impact its yield and quality making it a pressing issue that requires immediate attention. In this study, the sandwich method is employed to evaluate the allelopathic activity of different plant parts (leaves, stems, and roots) of Platycodon. The inhibitory effects of the various Platycodon plant parts were quantified based on their effects on lettuce seedlings growth by Sandwich method, with the following average inhibition percentages at 1 mg/ml (agar) of : leaves (79.4%, 61.8%), stems (58.0%, 45.7%), and roots (53.4%, 49.3%) for lettuce radicals and hypocotyls, respectively. At a concentration of 5 mg/ml, the inhibitory effects were as follow: leaves (91.9%, 72.2%), stems (79.5%, 60.3%), and roots (71.4%, 65.2%). Also, by employing the Plant Box method, it was determined that Platycodon root exudation. The growth inhibition rates of lettuce seedling roots and hypocotyls were 45.5% and 18.9%, respectively. The effect of activated carbon on the adsorption of allelopathic substances was investigated, and the results of the sandwich method with a concentration of 1 mg/ml showed the following growth inhibitory effects on lettuce seedlings and hypocotyls: roots (27.8%, 25.7%), leaves (13.3%, 25.7%), and stem (9.07%, 13.6%). The Plant Box method revealed average rates of inhibition of -16.7% and -4.70% on the growth of lettuce seedlings and hypocotyls, respectively. The results of this study demonstrated that activated carbon has a mitigating effect on the allelopathic inhibition associated with the different plant parts and root exudation of Platycodon, thus may provide a potential solution for overcoming obstacles associated with continuous cropping of Platycodon.

Smoked cigarette butts (SCB) can be used as precursors to obtain activated carbon (AC) due to their high carbon content related to the presence of cellulose acetate and components that are retained in the tobacco combustion process. In this way, it was analyzed how the process of pyrolysis or formation of char from this residue occurs, for this a study of the kinetics of formation of char is carried out by thermogravimetry, using three heating speeds 5, 10 and 15 °C/min. Based on the data obtained, mathematical models such as Kissenger - Akahira - Sunose (KAS), Starink (STK) and Ozawa - Flynn - Wall (OFW) were used in order to identify thermodynamic parameters through the energy of activation. The char obtained was subjected to an activation treatment with KOH in order to increase the surface area and pore volume, obtaining values of 433 m2/g of BET area and 0.25 cm3/g of micropore volume. Finally, the adsorbent was applied in the removal of Cr (VI) obtaining a Qmax capacity determined by the Langmuir model of 55.8 mg/g.

Alkali-activated materials, sometimes called geopolymers, can be used as alternative cementitious materials to conventional Portland cement. There is a significant current interest in these materials due to their low CO2 footprint. Typical applications of alkali-activated materials are within civil engineering, however, potential applications as well cementing material within oil & gas are also being studied with emerging interest. This paper presents a systematic study of compressive strength development from 1 to 28 days for metakaolin-based alkali-activated cement. The results show that compressive strength is highly dependent upon the initial Si/Al ratio in the mix design, as well as the concentration of the activator solution. Furthermore, due to the relatively low initial reactivity of the used metakaolin material, different types of co-binders were included in the slurry composition to improve early strength development. The two different co-binders tested were another, more reactive metakaolin material and Blast Furnace Slag (GGBFS). It was found that both these co-binders performed as intended, by ensuring early strength development via precipitation of K-A-S-H and C-A-S-H gels, respectively, and also by enabling subsequent strength development due to improved dissolution of the low-reactive metakaolin.

The dolomite dust-emulsified asphalt composite with excellent mechanical properties was successfully prepared using alkali activation. The effects of different alkali concentrations and emulsified asphalt contents on the mechanical properties of the materials were studied. The mechanical properties and microstructure of the composites were analyzed using compressive strength tests, bending strength tests, and SEM characterization. The experimental results show that the specimens have excellent mechanical properties: the 7-day compressive strength can reach 76.67 MPa, and the bending strength is about twice that of silicate-based geopolymer-emulsified asphalt composite. With an increase in emulsified asphalt content, the compressive strength of the samples decreases, while the bending strength increases first and then decreases. When the emulsified asphalt content is 1%, the bending strength of the sample is up to 28.81 MPa, which is 25% higher than that of the sample without emulsified asphalt. This indicates that an appropriate emulsified asphalt content can play a toughening role in the system, providing a new idea for designing high-toughness alkali-activated materials.

Benign design of alkali-activated slag/FA geopolymer paste has intriguing increasing attention for optimizing its service performance. Therefore, the replacement of fly ash (FA) with 10 wt% silica fume (SF) is investigated by mechanical strength after freeze-thawing cycles and microstructure characterization. The results show that an appropriate dosage (30 wt%) of slag is necessary to attain alkali-activated slag/FA geopolymer paste with excellent mechanical performance, and the SF/slag/FA (SF: slag: FA= 10:30:60, wt%) geopolymer paste exerts the compressive and flexural strength of 95.2 and 3.2 MPa, respectively. Meanwhile, the doped 10 wt% SF facilitates the propagation of (N, C)-A–S–H chains, rather than the formation of C-S-H gels, evidenced by the absent exothermic peak at about 861oC from the differential scanning calorimetry (DSC) curves, leading to the increases in the pores volume with a pore diameter<20 nm and tortuosity by mercury intrusion porosimeter (MIP) results, corresponding to an improved freezing-thawing resistance with the residual compressive strength of 52.8 MPa and the weight loss of 10.5% after 300 freeze-thawing cycles. It explores a cost-effective and benign facile approach to designing heating curing-free alkali-activated slag/FA geopolymer paste with good freezing-thawing resistance.

The fireproof design of geopolymer has intriguing increasing attention by adjusting multi-component metallurgical solid wastes, due to its low-carbon emission, cost-effectiveness, and environmental conservation. Herein, the effects of silica fume (SF) on the microstructure and mechanical properties of alkali-activated slag/FA (fly ash) pastes subjected to elevated temperatures (150, 500, 850, and 1200℃) are investigated, to clarify the fact that whether or not the SF generates positive roles in mechanical strength of slag/FA (slag: FA=30:70, wt.%) geopolymers during building fires. The results show that the replacement of FA with 10 wt% SF (silica fume) promotes the increasing pore volume with a diameter of 0.2~3 μm, leading to an increase in the compressive or flexural strength below 850℃, “right shifts” of the endothermic peak, appearing uniform and compact fracture surfaces. Meanwhile, the gehlenite and labradorite generate after exposure above 850℃. While the bloating effect of the SF-containing sample occurs at 1200℃, leading to a greater deformation, due to the further restructuring of the amorphous geopolymer chain N-A-S-H or N-(Ca)-A-S-H composed from the [SiO4]4− and [AlO4]5−. It explores an effective approach for improving geopolymer’s fireproof performance by adjusting the solid-waste formulation.

Activated Corrosion Products (ACPs) formation and deposition pose a critical safety issue for nuclear fusion reactors. The working fluid transports the ACPs towards regions accessible to worker personnel. Predicting ACPs formation deposition and transport is fundamental for source term identification, reduction of radiation exposure assessment, maintenance plan definition, design optimization, and waste management. The code OSCAR-Fusion has been developed by the CEA (France) to evaluate the ACPs generation and transport in closed water-cooled loops for fusion application. This work aims at assessing the impact of water chemistry on the transport, precipitation, and deposition of corrosion products for the EU-DEMO divertor Plasma Facing Unit Primary Heat Transfer System. Sensitivity analyses and uncertainty quantification are needed due to the multi-physics phenomena involved in ACPs formation and transport. The OSCAR-Fusion/RAVEN code coupling developed by the Sapienza University of Rome and ENEA has been used. This work presents the perturbation results of different parameters chosen for a closed water-cooled loop considering a continuous scenario of 1888 days. The aim of this work is to assess the variation of build-up of ACPs, perturbing the alkalizing agent concentration into the coolant and the corrosion and release rates of different materials.

In the study, ground granulated blast furnace slag was activated with a wide variety of sodium salts to compare the effect of their pH and anion size on the hydration progress and compressive strength development of GGBFS pastes. Research was carried out on samples activated with twelve different sodium salts, cured for one year. Changes in their phase composition (XRD), loss on ignition at different temperatures, expansion and microstructure (SEM+EDS) were examined over the entire curing period. Studies have shown that the presence of sodium ions is more important than the pH of the system, as activation took place even in the case of compounds whose solutions are characterized by low pH, such as sodium tartrate or phosphate. The compressive strength of the pastes ranged from approximately 8 to 65 MPa after one year of curing.