ARTICLE | doi:10.20944/preprints202305.0240.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Kitchen waste; Enzyme; Enzymatic hydrolysis; Biofertilizer
Online: 4 May 2023 (08:51:19 CEST)
The study addresses the management of kitchen waste by transforming it into biofertilizer formulations utilizing an effective in-house developed multi-enzyme preparation. A separate hydrolysis and fermentation bioprocessing approach which in particular relates to the application of a separate enzyme preparation from Aspergillus niger P-19 to separately hydrolyze kitchen waste, followed by the growth of Klebsiella pneumoniae AP-407 in the liquid hydrolysate as well with simultaneous production of carrier-based biofertilizer. In liquid and carrier-based biofertilizers, the viable cell count reaches 3.00 × 1012 CFU/ml and 3.00 × 1012 CFU/g, respectively. The current study adopts a novel process technique for the manufacturing of both carrier and liquid biofertilizers, adopting a zero-waste approach to the management of kitchen waste.
ARTICLE | doi:10.20944/preprints202208.0436.v1
Subject: Biology And Life Sciences, Endocrinology And Metabolism Keywords: tryptophan metabolites; microbiome; obesity; enzymatic landscape
Online: 25 August 2022 (13:21:39 CEST)
Indole and indole-3-lactate are known dominant microbial tryptophan catabolites (MICT). In obesity, the fecal indole concentration corresponds to the normal one, and that of indole-3-lactate significantly decreases along with other MICT, while it increases in blood plasma. During the analysis of the «enzymatic landscape» of the intestinal microbiota we find an almost twofold increase in the correlation between the concentrations of fecal MICT and the «enzymatic landscape», with indole-3-lactate having the closest relationships with the “enzymatic landscape” of all MICT. Here, we report statistically significant correlations of indole-3-lactate and the gut microbial enzymes for fructose, amino sugars, nucleotides, polyamines metabolism, and sulfoglycolysis. We also demonstrate that indole-3-lactate producing microbiota representatives increase three-fold in obesity. The phenotype of the microbiotic population is thus represented by completely different genera and species of microorganisms in obese individuals compared to healthy donors.
Subject: Chemistry And Materials Science, Biomaterials Keywords: enzyme; bast fibers; enzymatic retting; characterizations
Online: 26 November 2019 (10:27:02 CET)
Natural fibers are a gift from nature that we yet fully utilized until now. It can be classified into several groups and bast fibers are the group having the most promising performance when reinforced in polymer composites. However, numerous factors have been reported that influences mechanical properties of fiber reinforcements in the composite. In this review, bast fiber retting process and the effect of enzymatic retting on fiber and fibers reinforced polymer composites have been discussed and reviewed for the latest researches. Retting precedes mechanical processing (i.e. scutching) of the fiber from the stem and is essential for reduction of fiber breakage. All retting methods except chemical retting process are involving secretes of enzymes by bacteria or fungi under controlled (enzymatic retting) or random conditions (water and dew retting). Besides, enzymatic retting is claimed to have more environmentally friendly wastewater products, shorter retting period and controllable fiber biochemical components under mild incubation conditions. This review comprehensively assesses the enzymatic retting process for producing high-quality bast fiber and will become a reference for future development on bast fiber reinforced polymer composites.
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: nanocellulose; ionic liquids; Trichoderma reesei; enzymatic hydrolysis
Online: 11 May 2021 (10:42:38 CEST)
Nanocellulose has gained increasing attention during the past decade, which is related to its unique properties and wide application. In this paper, nanocellulose was produced by hydrolysis with ionic liquids (1-ethyl-3-methylimidazole acetate (EmimOAc) and 1-allyl-3-methylimidazolium chloride (AmimCl)) from microcrystalline cellulose (Avicel and Whatman) subjected to enzymatic pretreatment. The obtained material was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscope (SEM) and thermogravimetric analysis (TG). The results showed that the nanocellulose had a regular and spherical structure with a diameter of 30-40 nm and exhibited lower crystallinity and thermal stability than the material after hydrolysis with Trichoderma reesei enzymes. However, the enzyme-pretreated Avicel had a particle size of about 200 nm and a cellulose II structure. A two-step process involving enzyme-pretreatment and hydrolysis with ionic liquids resulted in the production of nanocellulose. Moreover, the particle size of nanocellulose and its structure depend on the ionic liquid used.
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: Cow milk; Enzymatic hydrolysis; Allergic protein; Antigenicity
Online: 19 October 2020 (11:04:35 CEST)
In this paper, the effects of different food-grade enzymes on the antigenicity of casein (CN), β- lactoglobulin (β-LG) and ɑ-lactalbumin (ɑ-LA) in natural cow milk were studied. The degree of hydrolysis (DH), SDS-PAGE and molecular mas (MW) distribution of cow milk (CM) hydrolysates was assessed. Additionally, the residual antigenicity of CM hydrolysates was evaluated by using ELISA and western blotting with anti-CN, anti-β-LG and anti-ɑ-LA rabbit polyclonal antibody. The results showed that Alcalase and Protamex hydrolysis could efficiently reduce the antigenicity of CN, β-LG, ɑ-LA, showed a higher DH and the loss of density of CM proteins, as indicated by SDS-PAGE. The increasing of the low MW (<3 kDa) in CM hydrolysates was also presented. It was also found that Protamex, Alcalase could be more efficiently hydrolyzed major allergenic of CM than other enzymes for the development of hypoallergenic cow milk. Our research will lay a theoretical foundation for the study of hypoallergenic cow milk.
ARTICLE | doi:10.20944/preprints202311.0837.v1
Subject: Chemistry And Materials Science, Applied Chemistry Keywords: wall painting; restoration; enzymatic cleaning; non-invasive diagnostics
Online: 13 November 2023 (15:58:04 CET)
A 17th century wall painting representing a Virgin between two Saints in a noble Italian renaissance palace, Palazzo Gallo in Bagnaia (Viterbo, Italy), was restored in 2021 in the context of a wider restoration campaign interesting the main room of the palace built by cardinal Sansoni Riario. Diagnostic analyses done with traditional characterization techniques (optical microscopy on micro-stratigraphic sections, X-ray fluorescence spectroscopy and Fourier transform infrared spectroscopy) provided the identification of both original painting and restoration materials, while imaging investigations as ultraviolet fluorescence photography, false color images and multispectral mapping provided by hypercolorimetric multispectral imaging (HMI) technique enabled the evaluation of the state of conservation, locating restoration interventions and supporting the monitoring of the cleaning procedure. An altered protective Paraloid-based coating dating from early 2000s had to be removed due to the unpleasant glossy finishing given to the painted surface, making the scene barely readable. To pursue a restoration protocol based on environmental sustainability and green chemistry, enzyme-based gels marketed by Nasier-Brenta© and CTS© companies were tested in different protocols for the cleaning of the mash covering the painting. Although some interesting results were observed, the enzymatic cleaning had a scarce effectiveness with timing beyond a reasonable interval. Traditional chemical solvents as Dowanol PM (methoxy-propanol) and benzyl alcohol were necessary to complete the cleaning of the painting surface.
ARTICLE | doi:10.20944/preprints202310.0610.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Gold nanostars; Enzymatic; Immobilized; Plasmonic; Colorimetric; Detection solution
Online: 10 October 2023 (08:51:28 CEST)
We describe a competitive colorimetric assay that enables rapid and sensitive detection of galactose and reduced nicotinamide adenine dinucleotide (NADH) via colorimetric readouts and demon-strates its usefulness for monitoring NAD+-driven enzymatic reactions. We present a sensitive plasmonic sensing approach for assessing galactose concentration and the presence of NADH using galactose dehydrogenase immobilized gold nanostars (AuNS-PVP-GalDH). The AuNS-PVP-GalDH assay remains turquoise blue in the absence of galactose and NADH; however, as galactose and NADH concentrations grow, the reaction well color changes to a characteristic red color in the presence of an alkaline environment and metal ions catalyst (detection solution). As a result, when galactose is sensed in the presence of H2O2, the colored response of the AuNS-PVP-GalDH assay transforms from turquoise blue to light pink, then to wine red in a con-centration-dependent manner discernible to the human eye. This competitive AuNS-PVP-GalDH assay could be a viable analytical tool for rapid and convenient galactose quantification in re-source-limited areas.
ARTICLE | doi:10.20944/preprints202304.0712.v1
Subject: Chemistry And Materials Science, Food Chemistry Keywords: carrot leaves; Daucus carota; enzymatic conversion; quantitative optimization
Online: 21 April 2023 (10:07:52 CEST)
In traditional oriental medicine, carrots (Daucus carota L.) are considered effective medicinal herbs; however, the use of D. carota leaves (DGL) as therapeutic agents has not been explored in depth. Therefore, we aimed to demonstrate the value of DGL, generally treated as waste while developing plants for wide industrial availability. Six flavone glycosides were isolated and identified from DGL, and their constituents were identified and quantitated using an NMR and HPLC/UV method, which was optimized and validated. The structure of chrysoeriol-7-rutinoside from DGL was elucidated for the first time. The method exhibited adequate relative standard deviation (<1.89%) and recovery (94.89–105.97%). The deglycosylation of DGL flavone glycosides by Viscozyme L and Pectinex was assessed. Upon converting the reaction contents to percentages, the luteolin, apigenin, and chrysoeriol groups showed values of 85.8, 33.1, and 88.7%, respectively. The enzyme-treated DGL had a higher inhibitory effect on TNF-α and IL-2 expression than that of the carrot roots or carrot leaves without enzyme treatments. These results highlight the importance of carrot leaves and could be used as baseline standardization data for commercial development.
ARTICLE | doi:10.20944/preprints202212.0059.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: nanocellulose; enzymatic synergism; optimal mixture; CCRD; Colby factor
Online: 5 December 2022 (06:03:10 CET)
A study to produce cellulose nanofibrils (CNF) from Kraft cellulose pulp, an optimal enzyme mixture, was defined using a centroid simplex mixture design. The enzyme blend contains 69% endoglucanase and 31% exoglucanase. The central composite rotational design (CCRD) optimized the CNF production process by achieving a higher crystallinity index. It thus corresponded to a solid loading of 15 g/L and an enzyme loading of 0.974. Using the Segal formula, the crystallinity index (CrI) of CNF was determined by X-ray diffraction to be 80.87%. The average diameter of nanocellulose fibers measured by scanning electron microscopy between 550 - 600 nm for the CNF prepared by enzymatic hydrolysis and between 250 - 300 nm for the CNF produced by enzymatic hydrolysis with the optimal enzyme mixture followed by ultrasonic dispersion. Finally, synergistic interactions between the enzymes involved in nanocellulose production were demonstrated, with Colby factor values greater than one.
ARTICLE | doi:10.20944/preprints202007.0726.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: Carboxymethylcellulose; Pectin; Plum; Qualitative attributes; Enzymatic activity; Postharvest
Online: 31 July 2020 (03:04:33 CEST)
Polysaccharide-based edible coatings are served as an attractive preservation method for postharvest maintenance of most fruits. The current study examined the effect of carboxymethylcellulose (CMC)- and pectin (Pec)- based edible coatings on weight loss, firmness, total soluble solids (TSS), pH¬, titratable acidity (TA), vitamin C (vit C), total phenolics, anthocyanin and flavonoid contents, total antioxidant capacity (based on DPPH) and the activities of peroxidase (POD), polyphenol oxidase (PPO) and polygalacturonase (PG) enzymes during cold storage. The results showed that each coating and their combinations caused positive effects in all measured parameters except weight loss. The applied coatings preserved firmness and improved total phenols, anthocyanin and flavonoid contents, antioxidant capacity and POD activity. In addition, the coatings retarded TSS and pH enhancement and TA and vit C loss and decreased PPO and PG activities. It could be stated that CMC at 1 % and Pec at 1.5 % separately demonstrated the best results at most measured parameters; and among the combinations 0.5 % Pec + 1.5 % CMC acted better than the other treatments. Henceforth, application of CMC and/or Pec and/or their combinations would be considered as favorable approaches to improve postharvest quality characteristics of plum fruit.
ARTICLE | doi:10.20944/preprints201903.0227.v2
Subject: Biology And Life Sciences, Horticulture Keywords: oxidative stress; enzymatic antioxidants; malondialdehyde; membrane permeability; chlorophyll
Online: 28 March 2019 (11:15:50 CET)
Scarcity of water is one of the most serious concerns in plant biology with diverse implications at all the levels of molecular, biochemical, and physiological phenomena of plant growth, development, and consequently the productivity. Most of the strategies to induce or enhance drought tolerance in plants are unreasonably expensive and/or time-consuming. Some studies conducted in the recent past have shown that plant growth regulators (PGRs) may induce/improve physiological tolerance in plants to cope with adverse environmental conditions including drought. The present study was aimed at investigating the effects of foliar spray of GABA (0, 1, 2, and 4 mM) applied 20 days following the germination of seeds, on vegetative growth, morphological characteristics, integrity of cell-membrane, and the levels of photosynthetic pigments and enzymatic antioxidants in carrot cvs. Supertaj and Bharat, grown under 100% and 50% field capacity of soil moisture. The treated and untreated (control) carrot plants were harvested and analyzed 2 weeks following the GABA application. The results revealed that foliar application of GABA improved the vegetative growth and significantly increased the levels of free amino acids, plastid pigments, enzymatic antioxidants, and the relative water content in the root crop grown under 50% field capacity of soil moisture, compared to control. Additionally, the GABA application decreased the electrolyte leakage of ions and melondialdehyde (MDA) content in carrot leaves. The carrots harvested from GABA-treated or untreated (control) plants were not significantly different for their protein contents. In conclusion, the incorporation of GABA in the production management of carrots may help plants to mitigate the adverse effects of water deficit stress.
ARTICLE | doi:10.20944/preprints201810.0597.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: NiFe alloy; graphene oxide; glucose; non-enzymatic sensor
Online: 25 October 2018 (06:20:16 CEST)
NiFe alloy nanoparticles/graphene oxide hybrid (NiFe/GO) was prepared for electrochemical glucose sensing. The as-prepared NiFe/GO hybrid was characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results indicated that NiFe alloy nanoparticles can be successfully deposited on GO. The electrochemical glucose sensing performance of the as-prepared NiFe/GO was studied by cyclic voltammetry and amperometric measurement. Results showed that NiFe/GO modified glassy carbon electrode had sensitivity of 173 μA mM−1cm−2 for glucose sensing with a linear range up to 5 mM, which was superior to commonly used Ni nanoparticles. Furthermore, high selectivity for glucose detection can be achieved by NiFe/GO. All the results demonstrated that NiFe/GO hybrid was promising for using in electrochemical glucose sensing.
ARTICLE | doi:10.20944/preprints201709.0143.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: fibrinolytic acticity; FGFC1; plasminogen activator; plasminogen; enzymatic kinetic
Online: 28 September 2017 (09:17:34 CEST)
A marine fibrinolytic compound FGFC1 enhancing fibrinolysis was obtained involving in enzymatic kinetic parameters of reciprocal activation system with single chain urokinase type plasminogen activator and plasminogen. FGFC1, a kind of bisindole alkaloid from a metabolite of rare marine fungi Starchbotrys longispora FG216, modulated enzymatic kinetic parameters including fibrinolytic reaction rate and fibrin degradation characteristics. The enzymatic kinetics of fibrinolysis was described based on enzymatic reaction of chromogenic-substrate associated with p-nitroaniline (p-NA). While single chain urokinase-type plasminogen activator (pro-uPA) actived plasminogen, Kcat and kcat/km increased significantly with increase of FGFC1 concentration. Moreover, Kcat and kcat/km exhibited 26.5-fold and 22.8-fold enhanced activity at the concentration of 40 μg•mL−1 of FGFC1, respectively. The results suggested that FGFC1 improved significantly the maximum catalytic efficiency and the total catalytic activity of fibrinolysis base on the reciprocal activation of pro-uPA and plasminogen. Km increased with increasing FGFC1 concentration, which indicated that FGFC1 decreased slightly the affinity activity of pro-uPA and plasminogen versus enzyme substrate. The marine bisindole alkaloid FGFC1 enhanced fibrinolysis which was taken on enzymatic kinetic characteristics.
ARTICLE | doi:10.20944/preprints202310.0410.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: enzymatic peeling; citrus segments; sensory properties; vitamin C; pasteurisation
Online: 7 October 2023 (11:52:07 CEST)
Ready-to-eat fresh fruit have an increasing presence in international markets due to its convenience and health benefits. However, these produces are highly perishable and efficient technologies to increase their shelf life are needed. In the present research, different citrus fruit species and cultivars from organic farming were assayed to obtain enzymatically citrus segments. The best results in terms of segment quality were observed for ‘Hernandina’ clementine which was chosen to make a new ready-to-eat produce based on peeled citrus segments packaged in glass jars with slight syrup made on citrus juice and organic sugar cane. The most appreciated syrup was those containing 50-50 (v/v) of ‘Fino’ lemon juice and ‘Hernandina’ clementine based on the sensory scores given by the panellists. In addition, different pasteurization treatments were assayed to preserve the new produce safety and nutritional and sensory quality properties during storage at cold temperature. Results showed that pasteurization treatment at 50 °C for 45 min could be enough to avoid microbial contamination with mesophilic and psychrophilic aerobic bacteria or yeast and mould and to maintain sensory properties until five weeks of storage at 4 °C. In addition, only a 10 % reduction of vitamin C was observed from fresh segments or syrup until the end of storage period, showing that the new ready-to-eat produce would conserve high bioactive compound content and health benefits after pasteurization and prolonged cold storage.
ARTICLE | doi:10.20944/preprints202309.0286.v1
Subject: Biology And Life Sciences, Horticulture Keywords: essential oil; enzymatic antioxidants; drought; glutathione; lipid peroxidation; proline
Online: 6 September 2023 (04:25:57 CEST)
As abiotic stress, drought limits plant growth and minimizes productivity. The increased request for valuable essential oil extracted from geranium (Pelargonium graveolens L.) is mainly associated with plant growth, which is adversely affected by drought. Melatonin (MT) has been used to enhance plant growth under abiotic stress, however, its impact to overcome drought stress of aromatic plants including geranium is poorly investigated. In the current investigation, MT application at 100 µM was applied under 100 % (well-watered) or 50 % (drought stress) of FC to verify this role. Drought stress markedly reduced growth parameters, herb yield, and total chlorophyll; however, MT alleviated these effects. In contrast, drought enhanced the essential oil percentage in geranium leaves. Despite the reduction in oil yield caused by drought, MT application mitigated this reduction and improved both oil yield and oil components. Besides, MT treatment enhanced the accumulation of total phenols, glutathione, and proline and improved the activity of ascorbate peroxidase, catalase, and glutathione reductase with possible alleviation of drought-induced oxidative damage. Therefore, it reduced both H2O2 and malondialdehyde accumulation, and finally maintained membrane integrity. Overall, this is the first report that reveals that MT application can improve geranium resistance to drought by enhancing the antioxidant potential and protecting the cell membrane from oxidative damage.
REVIEW | doi:10.20944/preprints202308.1504.v1
Subject: Chemistry And Materials Science, Electrochemistry Keywords: Copper oxide; Copper sulfide; Non-enzymatic; Glucose; Electrochemical; Sensor
Online: 22 August 2023 (09:54:35 CEST)
Millions of people worldwide are affected by diabetes, a chronic disease that continuously grows due to abnormal glucose concentration levels present in the blood. Monitoring blood glucose concentrations is therefore an essential diabetes indicator to aid in the management of the disease. Enzymatic electrochemical glucose sensors presently account for the bulk of glucose sensors in the market. However, their disadvantages are that they are expensive and are dependent on environmental conditions, hence affecting their performance and sensitivity. To meet the increasing demand, non-enzymatic glucose sensors based on chemically modified electrodes for the direct electrocatalytic oxidation of glucose are a good alternative to the costly enzymatic-based sensors currently on the market, and the research thereof continues to grow. Nanotechnology-based biosensors have been explored for their electronic and mechanical properties, resulting in enhanced biological signalling through the direct oxidation of glucose. Copper oxide and copper sulfide exhibit attractive attributes for sensor application, due to their non-toxic nature, abundance, and their unique properties. Thus, in this review, copper oxide and copper sulfide-based materials, are evaluated based on their chemical structure, morphology, and fast electron mobility as suitable electrode materials for non-enzymatic glucose sensors. The review highlights the present challenges of non-enzymatic glucose sensors that have limited their deployment into the market.
COMMUNICATION | doi:10.20944/preprints202308.1511.v1
Subject: Biology And Life Sciences, Biophysics Keywords: nanopore detector; solid-state nanopore; horseradish peroxidase; enzymatic activity
Online: 22 August 2023 (08:03:02 CEST)
We demonstrate the use of a nanotechnology-based approach for the investigation of enzymatic activity of a single molecule of horseradish peroxidase with a solid-state nanopore. The artificial 5 nm solid-state nanopore has been formed in a 40-nm-thick silicon nitride structure. Single molecule of HRP has been entrapped into the nanopore. The activity of horseradish peroxidase (HRP) enzyme molecule inserted in the nanopore has been monitored by recording the time dependence of the ion current through the nanopore in the course of the reaction of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) oxidation reaction. We have found that in the process of ABTS oxidation in the presence of 2.5 mM hydrogen peroxide, individual HRP enzyme molecules are able to retain activity for approximately 700 seconds before a decrease in the ion current through the nanopore, which can be explained by structural changes of the enzyme.
ARTICLE | doi:10.20944/preprints202307.1545.v1
Subject: Chemistry And Materials Science, Chemical Engineering Keywords: Sugarcane bagasse; Steam explosion; Enzymatic hydrolysis; Fermentation; Lactic acid
Online: 24 July 2023 (08:10:50 CEST)
This work aimed at producing lactic acid (LA) from sugarcane bagasse after steam explosion at 195 ºC for 7.5 and 15 min. Enzymatic hydrolysis was carried out with Novozymes’ Cellic CTec3 and/or Cellic HTec3, whereas fermentation was performed with Bacillus coagulans DSM2314. Water-washing of pretreated solids before enzymatic hydrolysis improved both hydrolysis and fermentation yields. The presence of xylo-oligosaccharides (XOS) in substrate hydrolysates reduced hydrolysis efficiency, but their effect on fermentation was negligible. The presence of fermentation inhibitors in C5 streams was circumvented by adsorption on activated carbon powder with no detectable sugar losses. High carbohydrates-to-LA conversions (Yp/s) of 0.88 g·g-1 were obtained from enzymatic hydrolysates of water-washed steam-exploded materials that were produced at 195°C, 7.5 min and the use of centrifuged-but-never-washed pretreated solids decreased Yp/s by 16%. However, when the detoxified C5 stream was added at a 10% ratio, Yp/s was raised to 0.93 g·g-1 for an LA productivity of 2.55 g·L-1·h-1. Doubling the pretreatment time caused a decrease in Yp/s to 0.78 g·g-1, but LA productivity was the highest (3.20 g·L-1·h-1). For pretreatment at 195°C for 7.5 min, elimination of water washing seemed feasible, but the use of longer pretreatment times made it mandatory to eliminate fermentation inhibitors.
REVIEW | doi:10.20944/preprints202307.1264.v1
Subject: Chemistry And Materials Science, Nanotechnology Keywords: biosynthesis; enzymatic activity; green synthesis; gold nanoparticles; silver nanoparticles
Online: 19 July 2023 (03:21:48 CEST)
Nanoparticles (NPs) have uniform chemical composition, size, and morphology. Microorganisms are of great interest in Nanoparticle synthesis. The green production of nanomaterials occurs either intracellularly or extracellularly. Gold and silver nanoparticles are mostly synthesised by the enzymatic degradation of metal ions. The produced NPs are characterized by different instruments such as ultraviolet visible, dynamic light scattering, x-ray diffraction, scanning electron microscope, transmission electron microscope, etc. Our review discusses the various biomedical applications of gold and silver nanoparticles synthesized by microbes via intracellular and extracellular mechanisms.
ARTICLE | doi:10.20944/preprints202212.0266.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: enzymatic hydrolysis; biomodified kraft pulp; cellulose; xylan; cryogel; crystallinity
Online: 15 December 2022 (06:23:58 CET)
The global development of bioeconomy is impossible without technologies for comprehensive processing of plant renewable resources. The use of proven pretreatment technologies raises the possibility of industrial implementation of enzymatic conversion of polysaccharides from lignocellulose considering the process complexity. For instance, a well-tuned kraft pulping produces a substrate easily degraded by cellulases and hemicelulases. Enzymatic hydrolysis of bleached hardwood kraft pulp was carried out using an enzyme complex of endoglucanases, cellobiohydrolases, b-glucosidases and xylanases produced by recombinant strains of Penicillium verruculosum at a 10 FPU/g mixture rate and a 10 % substrate concentration. As a result of biocatalysis the following products are obtained: sugar solution, mainly glucose, xylobiose, xylose, as well as other minor reducing sugars; modified complex based on cellulose and xylan. The composition of biomodified kraft pulp was determined involving the use of HPLC. The method for determining the degree of crystallinity on an X-ray diffractometer was used to characterize the properties. The article shows the possibility of producing modified cellulose cryogels by amorphization with concentrated 85 % H3PO4 followed by precipitation with water and supercritical drying. Analysis of the enzymatic hydrolysate composition reveals the predominance of glucose (55...67 %) in reducing sugars with a maximum content of up to 6 % in the solution after 72 hours. The properties and structure of modified kraft pulp were shown to change during biocatalysis, in particular, the degree of crystallinity increased by 5 % after 3 hours of enzymatic hydrolysis. We obtained cryogels based on the initial and biomodified kraft pulp with conversion rates of 35, 50 and 70 %. The properties of these cryogels are not inferior to those based on industrial microcrystalline cellulose, as confirmed by the specific surface area, degree of swelling, porosity and SEM images. Thus, kraft pulp enzymatic hydrolysis offers prospects not only for producing sugar-rich hydrolysates for microbiological synthesis, but also for producing cellulose powders and cryogels with specified properties.
ARTICLE | doi:10.20944/preprints202111.0130.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: biorefining; bran; enzymatic hydrolysis; green-extraction; hydroxycinnamates; sustainability; valorization
Online: 8 November 2021 (12:04:08 CET)
Biorefining by enzymatic hydrolysis (EH) of lignocellulosic waste material due to low costs and affordability has received enormous interest amongst scientists as a potential strategy suitable for the production of bioactive ingredients and chemicals. In the present study, a sustainable and eco-friendly approach to the extraction of bound ferulic acid (FA) has been demonstrated using a single-step EH by a mixture of lignocellulose-degrading enzymes. For comparative purposes of the efficiency of EH, an online SFE-SFC-MS extraction and analysis approach was applied. The experimental results demonstrated up to 369.3 mg 100 g−1 FA released from rye bran after 48 h EH with Viscozyme L. The EH of wheat and oat bran with Viscoferm for 48 h resulted in 255.1 and 33.5 mg 100 g−1 of FA, respectively. The extraction of FA from bran matrix using the SFE-CO2-EtOH delivered up to 464.3 mg 100 g−1 of FA, though the extractability varied depending on the parameters used. The 10-fold and 30-fold scale-up experiments confirmed the applicability of EH as a bioprocessing method valid for industrial-scale. The highest yield of FA in both scale-up experiments was obtained from rye bran after 48 h of EH with Viscozyme L. In purified extracts, the absence of xylose, arabinose, and glucose as final degradation products of lignocellulose was proven by a HPLC-RID system. Up to 94.0% purity of FA was achieved by SPE using the polymeric reversed-phase Strata X column and 50% EtOH as eluent.
REVIEW | doi:10.20944/preprints202101.0194.v1
Subject: Engineering, Automotive Engineering Keywords: ultrasound; ultrasonic reactors; enzyme kinetic; enzymatic reaction; sonochemical reaction
Online: 11 January 2021 (12:49:39 CET)
The use of low-intensity ultrasound has gotten surprising consideration over the last decade as a method for enhancing the catalytic activity of the enzyme. Ultrasounds have the potential to significantly influence the activity of the enzymatic processes, provided that the energy input is not too high to inactivate the enzyme. By providing the variation in parameters, various physical and chemical effects can be attained that can enhance the enzymatic reaction. Ultrasonic reactors are known for their application in bioprocesses. However, the potential of their applications is still limited broadly due to the lack of proper information about their operational and performance parameters. In this review, the detailed information about ultrasonic reactors is provided by defining the different types of reactors, number and position of ultrasonic transducers. Also, it includes the mechanism of intensification and influence of ultrasonic parameters (intensity, duty cycle and frequency) and enzymatic factors (enzyme concentration, temperature and pH) on the catalytic activity of enzyme during ultrasound treatment.
REVIEW | doi:10.20944/preprints202009.0449.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: oleaginous microorganisms; microbial lipids; lignocellulose pretreatment; enzymatic hydrolysis; inhibitors
Online: 19 September 2020 (05:16:42 CEST)
The microorganisms able of accumulating lipids in high percentages, known as oleaginous microorganisms, have been widely studied as an alternative for producing oleochemicals and biofuels. Microbial lipid, so called Single Cell Oil (SCO), production depends on several growth parameters, including the nature of the carbon substrate, which must be efficiently taken up and converted into storage lipid. Οn the other hand, substrates considered for large scale applications must be abundant and of low acquisition cost. Among others, lignocellulosic biomass is a promising renewable substrate containing high percentages of assimilable sugars (hexoses and pentoses). However, it is also highly recalcitrant and therefore it requires specific pretreatments in order to release its assimilable components. The main drawback of lignocellulose pretreatment is the generation of several by-products that can inhibit the microbial metabolism. In this review, we discuss the main aspects related to the cultivation of oleaginous microorganisms using lignocellulosic biomass as substrate, hoping to contribute to the development of a sustainable process for SCO production in the near future.
ARTICLE | doi:10.20944/preprints201902.0037.v1
Subject: Engineering, Energy And Fuel Technology Keywords: Biomass, valorisation, ionic liquid, crystallinity, enzymatic hydrolysis, pre-treatment
Online: 4 February 2019 (13:57:18 CET)
Ionic liquids have been recognised as interesting solvents applicable in the efficient lignocellulosic biomass valorisation, especially in the biomass fractionation into individual polymeric components or direct hydrolysis some of biomass fractions. Considering the chemical character of ionic liquids, two different approaches, paved the way for a fractionation of biomass. The first strategy integrated a pre-treatment, hydrolysis and conversion of biomass through the employment of hydrogen-bond acidic 1-ethyl-3-methyimidazolim hydrogen sulfate ionic liquid. The second one relied on the use of a three-step fractionation process with hydrogen-bond basic 1-ethyl-3-methylimidazolium acetate to produce high purity cellulose, hemicellulose and lignin fractions. The proposed approaches were scrutinised for wheat straw and eucalyptus residues. Those different biomasses allowed understanding that enzymatic hydrolysis yields are dependent on the crystallinity of pre-treated biomass. The use of acetate based ionic liquid allowed to change crystalline cellulose I to cellulose II and consequently enhanced glucan to glucose yield to 93.14.1 mol% and 82.91.2 mol% for wheat straw and eucalyptus, respectively. Whereas for hydrogen sulfate ionic liquid, the same enzymatic hydrolysis yields were 61.6 0.2 mol% for wheat straw and only 7.90.3 mol% for eucalyptus residues. These results demonstrate the importance of either ionic liquid character or biomass type on the efficient biomass processing.
ARTICLE | doi:10.20944/preprints201703.0032.v1
Subject: Chemistry And Materials Science, Applied Chemistry Keywords: organic pollutants; enzymatic remediation; sulforhodamine B; soybean peroxidase; chloroperoxidase
Online: 6 March 2017 (07:45:32 CET)
Enzymatic degradation of organic pollutants is a new and promising remediation approach. Peroxidases are one of the most commonly used classes of enzymes to degrade organic pollutants. However, it is generally assumed that all peroxidases behave similarly and produce similar degradation products. In this study, we conducted detailed studies of the degradation of a model aromatic pollutant, Sulforhodamine B dye (SRB dye), using two peroxidases—soybean peroxidase (SBP) and chloroperoxidase (CPO). Our results show that these two related enzymes had different optimum conditions (pH, temperature, H2O2 concentration...etc.) for efficiently degrading SRB dye. High-performance liquid chromatography and LC-mass spectrometry analyses confirmed that both SBP and CPO transformed the SRB dye into low molecular weight intermediates. While most of the intermediates produced by the two enzymes were the same, the CPO treatment produced at least one different intermediate. Furthermore, toxicological evaluation using lettuce (Lactuca sativa) seeds demonstrated that the SBP-based treatment was able to eliminate the phytotoxicity of SRB dye, but the CPO-based treatment did not. Our results show, for the first time, that while both of these related enzymes can be used to efficiently degrade organic pollutants, they have different optimum reaction conditions and may not be equally efficient in detoxification of organic pollutants.
COMMUNICATION | doi:10.20944/preprints202312.0202.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: bioactive peptides; enzymatic protein hydrolysis; membrane filtration; purification; LC-OCD.
Online: 4 December 2023 (12:03:34 CET)
Membrane processes, such as microfiltration, ultrafiltration, and nanofiltration are increasingly used for various applications in both upstream and downstream processing. Membrane-based processes play a critical role in the field of separation/purification of biotechnological products, including protein production/purification. The possibility of using membranes to separate peptides from a chicken byproduct hydrolysate and the effect of the performed downstream processing on the DPP-IV inhibitory activity of MDCR (mechanical deboning chicken residue) has been investigated. The chicken byproduct hydrolysate was prepared by enzymatic hydrolysis followed by MF, UF, NF, and RO separation. The LC-OCD analysis confirmed that NF and RO would retain the bioactive peptides in the concentrate in comparison to MF and UF. Bioactivity was correlated with molecular weight distribution profiles and average molecular weights. Permeates after ultrafiltration showed an IC50 value of 0.75 mg/mL, comparable to other potent DPP-IV inhibitors derived from various food sources, and significantly more potent compared to the microfiltration sample, which showed an IC50 value of 1.04 mg/mL. The average molecular weight of the permeates calculated from the SEC chromatograms was 883 g/mol for UF and 1437 g/mol for MF. Of the four membranes studied, the UF membrane showed the best separation properties with respect to maximizing the yield and up-concentration of the bioactive peptides. Overall, UF was demonstrated to be a feasible technology for the removal of the undesired high molecular weight substances and up-concentration of small molecular weight bioactive peptides from chicken byproduct hydrolysate.
ARTICLE | doi:10.20944/preprints202308.1295.v1
Subject: Medicine And Pharmacology, Pediatrics, Perinatology And Child Health Keywords: Mucopolysaccharidosis; lysosomal storage disorder; newborn screening; enzymatic testing; genetic testing
Online: 18 August 2023 (09:45:16 CEST)
Introduction: Mucopolysaccharidosis type I (MPSI) is an autosomal recessive lysosomal storage disorder characterized by deficient or absent α-L-iduronidase (IDUA) enzyme activity due to pathogenic variants in IDUA gene. Early treatment with hematopoietic stem cell transplantation and/or enzyme replacement therapy is associated with improved outcomes in this progressive multisystem disease. The diagnosis is usually delayed due to late presentation and nonspecific symptoms resulting in high morbidity and mortality. The incidence of MPSI in US is estimated to be 0.26:100,000, however, it is unknown in Kuwait. This pilot study was undertaken to screen MPSI in all Kuwaiti neonates born at Farwaniya Hospital over a period of 12-months. This study examined the incidence of MPSI in a major center in Kuwait for inclusion in the national newborn screening program to enable its early detection and adequate treatment. Methods: All Kuwaiti neonates born at Farwaniya Hospital, Kuwait from December 2021 to December 2022, were screened for MPSI. The screening consisted of determining IDUA enzyme activity in dried blood spots (DBS)-derived samples by Tandem Mass Spectrometry. A follow-up genetic analysis of IDUA gene is planned to screen the cases with diminished IDUA enzyme activity as second-tier testing. Results: A total of 618 newborns, including 331 (54%) males and 287 (46%) females, were screened. Twenty of them had deficient IDUA enzyme activity but showed negative genetic testing for IDUA. However, we have diagnosed one additional female baby with MPSI, who belonged to Farwaniya Hospital, but the parents chose to deliver in a private hospital. She presented at age three months with recurrent upper airway infections, snoring and extensive Mongolian spots. The molecular study revealed previously reported pathogenic nonsense variant in IDUA c.1882C>T; p.(Arg628Ter), associated with severe phenotype. That being included, MPSI is estimated to be about 0.3% among tested females and 0.2% of all screened cases in Kuwait. Conclusion: Our study is the first to evaluate the incidence of MPSI in Kuwait. Given the single center, small number of screened babies and the short study duration thus far, it is premature to calculate the incidence of MPSI. It is anticipated that as the study continues and more infants are examined, we would be able to estimate the incidence of this disease in our population correctly. Further studies including screening newborns in all maternity hospitals in Kuwait are needed to calculate the actual incidence of MPSI. Our data supports including MPSI in national newborn screening program to allow early initiation of treatment and thus improve disease outcome.
ARTICLE | doi:10.20944/preprints202307.1600.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: beef potentiator; enzymatically hydrolyzed beef liquid; ultrasound; enzymatic hydrolysis; flavor
Online: 24 July 2023 (10:39:34 CEST)
Beef potentiator is an important flavor enhancer in food industry, while it is prone to generating insufficient taste compounds and off-odor compounds during enzymatic hydrolysis of beef, resulting in poor flavor of beef potentiator. It has been extensively reported that sonication is capable of improving food flavor. However, the effect of sonication on the flavor of enzymatically hydrolyzed beef liquid (EHBL) was scarcely reported. Herein, we investigated the effect of sonication on the flavor of EHBL using quantitative descriptive analysis (QDA), physicochemical analysis and SPME-GC-olfactometry/MS. QDA showed that sonication had a significant effect on taste improvement and off-odor removal of EHBL. Compared with the control, sonication (40 kHz, 80 W/L) increased the contents of total nitrogen, formaldehyde nitrogen, total sugar, reducing sugar, free amino acids (FAAs) and hydrolysis degree of EHBL by 19.25%, 19.80%, 11.83%, 9.52%, 14.37% and 20.45%. Notably, sonication markedly enhanced the contents of sweet FAAs, umami FAAs and bitter FAAs of EHBL by 19.66%, 14.04% and 9.18%, respectively, which contributed to the taste improvement of EHBL. SPME-GC-olfactometry/MS analysis showed that aldehydes and alcohols were the main contributors to aroma compounds of EHBL, sonication significantly increased the contents of key aroma compounds and 115.88% of alcohols content in EHBL. Notably, sonication decreased contents of the fishy odorants, hexanoic acid and nonanal, markedly by 35.29% and 26.03%, which was responsible for the aroma improvement of EHBL. Therefore, sonication could become a new potential tool to improve the flavor of EHBL.
ARTICLE | doi:10.20944/preprints202304.0696.v1
Subject: Medicine And Pharmacology, Pharmacy Keywords: oligonucleotide conjugation; anisamide; anti-enzymatic stability; cellular uptake; antitumor activity
Online: 21 April 2023 (08:53:24 CEST)
Antisense oligonucleotides (ASONs) have proven potential for the treatment of various diseases. However, their limited bioavailability restricts their clinical application. New structures with improved enzyme resistance stability and efficient drug delivery are needed. In this work, we propose a novel category of ASONs bearing anisamide conjugation at phosphorothioate sites for oncotherapy. ASONs can be conjugated with the ligand anisamide very efficiently and flexibly in solution. The conjugation sites and ligand amount both influence anti-enzymatic stability and cellular uptake, resulting in changes in antitumor activity that are detectable by cytotoxicity assay. T6 (with double end AA-conjugation) was identified as the optimal conjugate, and its antitumor activity and the underlying mechanism were examined further in vitro and in vivo. This paper presents a new strategy for the design of nucleic acid–based therapeutics with improved drug delivery and biophysical and biological efficacy.
ARTICLE | doi:10.20944/preprints202208.0271.v1
Subject: Chemistry And Materials Science, Inorganic And Nuclear Chemistry Keywords: non-enzymatic sensor; glucose; cobalt metal-organic framework; electrochemical detection
Online: 16 August 2022 (03:26:09 CEST)
The integration of metal nanoparticles and solid carriers can achieve ideal stability, high load and good conductivity. In this work, copper nanoparticles (Cu NPs) were sequentially deposited on a cobalt metal-organic framework (Co-MOF) by bonding with exposed imino groups, followed by a reduction reaction to prepare a new Cu@Co-MOF composite. Cu@Co-MOF acts as a non-enzymatic electrochemical sensor to detect glucose (Glu) in an alkaline medium. The composite working electrode of Cu@Co-MOF/GCE (GCE = glassy carbon electrode) improves the electrocatalytic activity for Glu oxidation. Cu@Co-MOF/GCE shows excellent electrocatalytic performances in Glu concentration ranging 0.005~1.8 mmol∙L−1 (mM): the sensitivities are 282.89 μA∙mM−1∙cm−2 in 0.005-0.4 mM Glu and 113.15 μA∙mM−1∙cm−2 in 0.4-1.8 mM Glu respectively with low detection limit of 1.6 μM (S/N = 3) and high selectivity and stability.
ARTICLE | doi:10.20944/preprints201810.0590.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: biofortification; antioxidants; soilless culture; nutraceutical quality; enzymatic activity; plant resistance
Online: 25 October 2018 (05:22:51 CEST)
Selenium (Se) is an essential element of the human diet. Therefore, it is necessary to implement Se in agricultural fertilization, although it is not considered as an essential element for plants, Se provides benefits at the level of redox metabolism, increasing the resistance of plants to various stress factors. The increase of the availability of selenium with the use of biopolymer complexes was sought in Great Lakes lettuce grown in substrate pots treated with SeO2 (5 mg L Se), Cs-PAA + Se (5 mg L Se), and Cs-PAA. The redox metabolism was modified by increasing the enzymatic activity of glutathione peroxidase. The use of Cs-PAA + Se biopolymer complexes increase selenium up to 24 mg/Kg dry weight (DW) in plant tissues.
REVIEW | doi:10.20944/preprints202307.0526.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: colorimetric; dual ratiometric; biosensor; enzymatic; acetylcholinesterase; plant and animal derived-food
Online: 10 July 2023 (11:12:40 CEST)
Pesticides are chemical products are used to protect crops to prevent or eliminate undesirable organisms. Pesticides can contaminate continental waters, air, soil and food products. The presence of pesticide residues must therefore be monitored in water and food using sensitive, reliable and broad-spectrum analytical methods, as there is a huge variety of pesticides. Biosensors are one of the screening methods with great potential for detecting residues below the maximum residue limits. The different sensing principles of enzymatic biosensors for pesticide analysis will be described. This review highlights the great potential of colorimetric, enzymatic biosensors for detecting pesticide residues in water and food. Moreover the development of dual colorimetric and fluorimetric sensors during the past years is presented. These methods are most often based on the enzyme acetylcholinesterase, whose activity is inhibited by pesticides. The different approaches used in the development of these biosensors will be detailed, based on different chemical substrates, fluorophores and nanomaterials. The advantages and disadvantages of each approach will be discussed. Finally, the development prospects for improving these biosensors will be presented.
ARTICLE | doi:10.20944/preprints202305.0635.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Potato peels; Pre-treatment; Multiple enzyme system; Enzymatic saccharification; Fermentation; Bioethanol
Online: 9 May 2023 (10:25:43 CEST)
The aim of this study was to investigate the potential of converting potato peel waste into bio ethanol using an in-house produced multi-enzyme preparation. To achieve this, a variety of pre-treatment strategies, including thermal, chemical, and thermo-chemical methods, were applied to the potato peels. These included boiling for 30 and 60 min, steam at varying pressures and times, and different concentrations of chemicals such as H2SO4, HNO3, CH3COOH, HCl, NaOH, Ca(OH)2, KOH, NH3, and H2O2, either alone or in combination with steam. The pre-treated potato peels were then enzymatically hydrolyzed using a crude multi-enzyme cocktail derived from solid-state fermentation of wheat bran by a natural variety of Aspergillus niger P-19, containing cellulases, hemicellulases, pectinase, and amylases. The most effective pre-treatment combination was found to be 3% H2SO4 followed by steam under pressure and enzymatic hydrolysis using the crude multi-enzyme preparation. This combination resulted in the highest yield of reducing sugars (141.04 ±12.31 g/l) with a 98.49% carbohydrate conversion at a 20% substrate loading, giving an ethanol yield of 43.2 g/l. Furthermore, supplementing the medium with peptone, (NH4)(H2PO4), and ZnSO4 at 0.1%w/v each with 22% and 24% solid, respectively, resulted in appreciable yields of 51.67 and 54.75 g/l, further enhancing the ethanol yield.
ARTICLE | doi:10.20944/preprints202212.0566.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Alternaria alternata; pear pathogens; multi-infections; enzymatic activities; mycotoxins; plant necrosis.
Online: 30 December 2022 (01:57:03 CET)
This lack of information is due to the primary role of HSTs in fungal pathogenesis, which often masks the functions of NSTs and CWDEs. So, the toxic effects of A. alternata metabolites due to NSTs and CWDEs have received minor attention than those reported for HSTs mycotoxins . A wider study of the activity of isolated fungal metabolites can allow the identification of compounds directly related to the pathogenic activity of the fungus, making it possible to create chemo libraries that facilitate the linking of the structure of the compounds with the species that produce it and its effect on host and non-host crops, as well as with biosynthetic features . In this context, our work reports a study focused on NSTs and CWDEs used by an A. alternata strain isolated from infected pears in Italy. To this aim, the characterization of hydrolytic enzyme activities of A. alternata and the identification of the metabolites produced in vitro were performed. Furthermore, the phytotoxic activity of the isolated compounds was evaluated on pear (host and non-host varieties) and lemon fruits . Finally, the competition of A. alternata with other pathogens was evaluated to investigate the role of NSTs on co-infections.
ARTICLE | doi:10.20944/preprints201809.0575.v1
Subject: Chemistry And Materials Science, Chemical Engineering Keywords: melanin like nanoparticles; sodium periodate; enzymatic activity; layer-by-layer films
Online: 29 September 2018 (04:16:12 CEST)
Polydopamine (PDA) deposition, obtained from the oxidation of dopamine and other catecholamines is an universal way to coat all known materials with a conformal coating which can subsequently be functionalyzed at will. The structural analogies between polydopamine and eumelanin, the black-brown pigment of the skin, incited to produce stable polydopamine nanoparticles in solution instead of amorphous precipitates obtained from the oxidation of dopamine. Herein, we demonstrate that size controlled and colloidally stable PDA based nanoparticles can be obtained in acidic conditions, where spontaneous auto-oxidation of dopamine is suppressed, using sodium periodate as the oxidant and a protein like alkaline phosphatase as a templating agent. The size of the PDA@Alp nanoparticles depends on the dopamine/enzyme ratio and the obtained particles display the enzymatic activity of alkaline phosphatase with an activity extending up to two weeks after particle synthesis. The PDA@ alkaline phosphatase (Alp) nanoparticles can be engineered in polyelectrolyte multilayered films to potentially design model biosensors.
ARTICLE | doi:10.20944/preprints201711.0074.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: cuprous oxide; non-enzymatic glucose sensor; alkaline solution; differential pulse voltammetry
Online: 13 November 2017 (03:15:30 CET)
A cuprous oxide (Cu2O) thin layer served as the base for a non-enzymatic glucose sensor in an alkaline medium, 0.1 NaOH solution, with a linear range of 50-200 mg/dL using differential pulse voltammetry (DPV) measurement. An X-ray photoelectron spectroscopy (XPS) study confirmed the formation of the cuprous oxide layer on the thin gold film sensor prototype. Quantitative detection of glucose in both phosphate-buffered saline (PBS) and undiluted human serum were carried out. Neither ascorbic acid nor uric acid even at a relatively high concentration level of 100mg/dL in serum interfered with the glucose detection, demonstrating the excellent selectivity of this non-enzymatic cuprous oxide thin layer based glucose sensor. Chronoamperometry (CA) and single potential amperometric voltammetry were used to verify the measurements obtained by differential pulse voltammetry (DPV), and the positive results validated that the detection of glucose in a 0.1 M NaOH alkaline medium by DPV measurement was effective. Nickel, platinum and copper are commonly used metals for non-enzymatic glucose detection. The performance of these metal-based sensors for glucose detection using DPV were also evaluated. Cuprous oxide (Cu2O) thin layer based sensor showed the best sensitivity for glucose detection among the sensors evaluated.
ARTICLE | doi:10.20944/preprints202310.0476.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: non-enzymatic sensor; Ag/δ-FeOOH; carbon black; hydrogen peroxide; electrochemical detection
Online: 10 October 2023 (03:13:13 CEST)
Hydrogen peroxide (H2O2) is an essential analyte for detecting neurodegenerative diseases and in-flammatory processes and plays a crucial role in pharmaceutical, food industry, and environmental monitoring. However, conventional H2O2 detection methods have drawbacks such as lengthy analysis time, high costs, and bulky equipment. Non-enzymatic sensors have emerged as promising alternatives to overcome these limitations. In this study, we introduce a simple, portable, and cost-effective non-enzymatic electrochemical sensor based on carbon black (CB) and silver nano-particle-modified δ-FeOOH (Ag/δ-FeOOH), integrated into a disposable electrochemical cell (DCell). Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and electrochemical impedance spectroscopy (EIS), confirmed successful CB and Ag/δ-FeOOH immo-bilization on the DCell working electrode. Electrochemical investigations revealed that the DCell-CB//Ag/δ-FeOOH sensor exhibited an approximately twofold higher apparent heterogene-ous electron transfer rate constant than the DCell–Ag/δ-FeOOH sensor, capitalizing on CB ad-vantages. Moreover, the sensor displayed excellent electrochemical response for H2O2 reduction, boasting a low detection limit of 22 µM and a high analytical sensitivity of 214 μA mM-1 cm-2. Notably, the DCell-CB//Ag/δ-FeOOH sensor exhibited outstanding selectivity for H2O2 detection, even in potential interferents such as dopamine, uric acid, and ascorbic acid. Furthermore, the sensor demonstrated its suitability for monitoring H2O2 in complex biological samples, as evidenced by H2O2 recoveries ranging from 92% to 103% in 10% fetal bovine serum. These findings underscore the considerable potential of the DCell-CB//Ag/δ-FeOOH sensor for precise and reliable H2O2 monitoring in diverse biomedical and environmental applications.
ARTICLE | doi:10.20944/preprints202309.1309.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: wood lignocellulose; pretreatment; enzymatic saccharification; glucose; kraft pulping; sulfite delignification; biomodified pulp
Online: 20 September 2023 (08:02:44 CEST)
Sulfite and kraft pulping are two principal methods of industrial delignification of wood. In recent decades, those have been considered as possibilities to pretreat recalcitrant wood lignocellulosics for enzymatic hydrolysis of polysaccharides and subsequent fermentation of obtained sugars to valuable bioproducts. Current work compares chemistry and technological features of two different cooking processes in the preparation of polysaccharide substrates for deep sacchari-fication with P. verruculosum glycosyl hydrolases. Bleached kraft and sulfite pulps were subjected to hydrolysis with enzyme mixture of high xylanase, cellobiohydrolase and β-glucosidase activities at a dosage of 10 FPU/g of dry pulp and fiber concentration of 2.5, 5 and 10%. HPLC was used to analyze soluble sugars after hydrolysis and additional acid inversion of oligomers to monosaccharides. Kraft pulp demonstrated higher pulp conversion after 48 h (74-99%), mostly resulted from deep xylan hydrolysis. Sulfite-pulp hydrolysates, obtained in similar conditions, due to higher hexose concentration (more than 50 g/L), had higher fermentability for industrial strains producing alcohols, microbial protein or organic acids. Along with saccharification, enzymatic modification of non-hydrolysed residues occurred, which led to decreased degree of polymerization and composition changes in two industrial pulps. As a result, crystallinity of kraft pulp increased by 1.3%, which opens possibilities for obtaining new types of cellulosic products in pulp and paper industry. The high adaptability and controllability of enzymatic and fermentation processes creates prospects for the modernization of existing factories.
ARTICLE | doi:10.20944/preprints202306.1939.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: plastic biodegradation; marine PET hydrolase; enzymatic degradation; indole-based polyesters; PETase; PET.
Online: 27 June 2023 (16:24:19 CEST)
Enzymatic polyethylene terephthalate (PET) recycling processes are gaining interest for their low environmental impact, use of mild conditions, and specificity. Furthermore, PET hydrolase enzymes are continuously being discovered and engineered. In this work, we studied a PET hydrolase (PET2), initially characterized as an alkaline thermostable lipase. PET2 was produced in a fusion form with a 6-histidine tag in the N-terminal. The PET2 activity on aromatic terephthalate and new indole-based polyesters was evaluated using polymers in powder form. Compared with IsPETase, an enzyme derived from Ideonella sakaiensis, PET2 showed a lower PET depolymerization yield. However, interestingly, PET2 gave significantly higher polybutylene terephthalate (PBT) and polyhexylene terephthalate (PHT) depolymerization yields. A clear preference was found for aromatic indole-derived polyesters over non-aromatic ones. No activity was detected on Akestra™, an amorphous copolyester with spiroacetal structures. Docking studies suggest that a narrower and more hydrophobic active site reduces its activity on PET but favours its interaction with PBT and PHT. Understanding the enzyme preferences of polymers will contribute to their effective use to depolymerize different types of polyesters.
ARTICLE | doi:10.20944/preprints202306.1309.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: Enzymatic hydrolysis; Glycine max; Bacillus velezensis KMU01; inflammation; dextran sulfate sodium; colitis
Online: 19 June 2023 (07:13:51 CEST)
The purpose of this study was to investigate the effect that Glycine max hydrolyzed with enzymes from Bacillus velezensis KMU01 has on dextran sulfate sodium (DSS)-induced colitis in mice. Hydrolysis improves functional health through the bioconversion of raw materials and increase in intestinal absorption rate and antioxidants. Therefore, G. max was hydrolyzed in this study using a food-derived microorganism, and its anti-inflammatory effect observed. Enzymatically hydrolyzed G. max (EHG) was orally administered once daily for four weeks before DSS treatment. Colitis was induced in mice through consumption of 5% (w/v) DSS in drinking water for eight days. Results showed that EHG treatment significantly alleviated DSS-induced body weight loss and decreased the disease activity index and colon length. In addition, EHG markedly reduced tumor necrosis factor-a, interleukin (IL)-1b, and IL-6 production, and increased that of IL-10. EHG improved DSS-induced histological changes and intestinal epithelial barrier integrity in mice. Moreover, we found that the abundance of 15 microorganisms changed significantly; that of Proteobacteria and Escherichia coli, which are upregulated in patients with Crohn’s disease and ulcerative colitis, decreased after EHG treatment. These results suggest that EHG has a protective effect against DSS-induced colitis and is a potential candidate for colitis treatment.
ARTICLE | doi:10.20944/preprints202207.0085.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Crown of thorns starfish (CoTS); actinomycetes; venom extract; anti-enzymatic; antibacterial activity
Online: 6 July 2022 (04:03:02 CEST)
Crown of thorns starfish (Acanthaster planci) are coral predators with advantages of having toxicity in their venom and tissue regeneration capabilities. With all these characteristics, only a handful of studies have highlighted the association of microorganisms with this organism. Crown of thorns starfish are common in Fiji and their analyses of microbial diversity for secondary metabolites could be of great interest to the scientific community. This study is an attempt to investigate Fijian-based A. planci for their venom and associated actinomycetes antibacterial activity and further identify the type of enzymes present in the crude venom extract. The CoTS venom extract (0.192 g) harbor enzymes such as gelatinase, caesinase, and amylase. An abundant and potent actinomycete strain, represented as FJA1 showed antibacterial activity against Enterococcus faecium with an inhibition zone of 10 mm. Moreover, all pathogenic test microorganisms were resistant against concentrations of 500 µg and 1 mg of A. planci venom extract.
ARTICLE | doi:10.20944/preprints202204.0236.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: biorefining; by-products; enzymatic hydrolysis; essential fatty acids; green-extraction; lipids; sustainability
Online: 26 April 2022 (10:37:03 CEST)
The main intention of the present work was to investigate the ability of cellulose-degrading enzymes (C-DE) to release fatty acids (FAs) from complex matrices of cereal by-products during enzymatic hydrolysis (EH). For this purpose, three types of cereal bran (CB), i.e., wheat, rye, and oat were used as a lignocellulose substrate for three commercially available hydrolytic enzymes, i.e., Viscozyme L, Viscoferm, and Celluclast 1.5 L. The yield and composition of FAs after EH was assessed and confronted with the yield obtained after either conventional Soxhlet extraction or alkaline-assisted hydrolysis (A-AH) with 10% KOH in 80% MeOH and subsequent liquid-liquid extraction. The experimental results demonstrated that up to 6.3% and 43.7% higher total FAs yield can be achieved within EH of rye bran using Celluclast 1.5 L than by A-AH and Soxhlet extraction, respectively. However, the application of Viscoferm for EH of wheat bran ensured up to 7.7% and 13.4% higher total FAs yield than A-AH and Soxhlet extraction, respectively. The concentration of essential linolenic acid (C18:3) in lipids extracted after EH of rye bran with Celluclast 1.5 L was up to 24.4% and 57.0% higher than in lipids recovered by A-AH and Soxhlet extraction, respectively. In turn, the highest content of linolenic in wheat bran lipids was observed after EH with Viscoferm and Viscozyme L, ensuring 17.0 and 13.6% higher yield than after A-AH, respectively. SEM analysis confirmed substantial degradation of CB matrix promoted by the ability of C-DE to act specifically on 1,4-β-D-glycosidic bonds in cellulose and on 1,2-α-,1,3-α-, and 1,5-α-L- arabinofuranoside and 1,4-β-D-xylosidic bonds in arabinoxylans, arabinans, and other arabinose-containing hemicelluloses. Structural alteration in cells integrity greatly contributed to the release of bound FAs and their better transfer into the extraction solvent. It has been shown that the proposed process of EH can be used for the efficient release of FAs from the CB matrix more sustainably and with a safer profile, thereby representing the further sustainable production of FAs for certain purposes.
REVIEW | doi:10.20944/preprints202104.0652.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Enzymatic reaction; crosslinking; Hydrogel; Biomedical application; Tissue engineering; Wound healing; Drug delivery
Online: 26 April 2021 (10:52:24 CEST)
Self-assembled structures mostly arises through enzyme-regulated phenomena in nature under persistent conditions. Enzymatic reactions are one of main biological processes in fabrication and construction of supramolecular hydrogel networks required for biomedical applications. The enzymatic processes provide a unique opportunity to integrate hydrogel formation. In most of cases, structure and substrates of hydrogels are adjusted by enzyme catalysis due to the chemo-, regio- and stereo-selectivity of enzymes. Hydrogels processed by using various enzyme schemes showed remarkable characteristics as dynamic frames for cells, bioactive molecules and drugs in biomedical applications. A novel class of enzyme-mediated crosslinking hydrogels mimics the extracellular matrices by displaying unique physicochemical properties and functionalities like water-retention capacity, drug loading ability, biodegradability, biocompatibility, biostability, bioactivity, optoelectronic properties, self-healing ability, shape memory ability. In recent years, many enzymatic systems investigated hydrogel cross-linking. Results of biocompatible hydrogel products show that these mechanisms of crosslinking can fulfill requirements for variety of biomedical applications including tissue engineering, wound healing and drug delivery.
ARTICLE | doi:10.20944/preprints202011.0195.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: codfish; enzymatic hydrolysis; proteomics; bioinformatic prediction; emulsifying properties; antioxidative activity; bioactive peptides
Online: 4 November 2020 (12:44:08 CET)
Protein hydrolysates show great promise as bioactive food and feed ingredient and for valorization of side-streams from e.g. the fish processing industry. This study characterizes bulk emulsifying, foaming, and in vitro antioxidative properties of hydrolysates derived from cod frame by application of Alcalase and Neutrase, individually and sequentially as well as the influence of heat-treatment prior to hydrolysis. We present a novel approach that utilizes proteomics data for calculation of weighted mean peptide properties (length, molecular weight, and charge) and peptide-level abundance estimation. Using subsequent bioinformatic prediction of biofunctional properties to describe observed bulk properties, we are able to provide an in-depth hydrolysate characterization not previously seen. All hydrolysates displayed comparable or higher emulsifying activity and stability than sodium caseinate. Heat-treatment significantly increased stability but showed a negative effect on the activity and degree of hydrolysis. Combining peptide abundance with predicted emulsifying activity, we were able to identify several peptides that are likely linked to the observed differences in bulk emulsifying properties. In general, decreased hydrolysis resulted in significantly higher chelating activity, while the opposite was observed for radical scavenging activity. The study highlights the prospects of applying proteomics and bioinformatics for hydrolysate characterization and in food protein science.
ARTICLE | doi:10.20944/preprints202005.0427.v2
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Isolation; Neural Crest-derived Stem Cells; Mechanical Dissociation; Regenerative Periodontology, Enzymatic Digestion
Online: 2 November 2020 (11:35:16 CET)
Periodontitis is microbial infection affecting periodontium, the tooth supporting structure and affects >743 million people worldwide. Neural crest-derived stem cells (NCSCs) hold the promise to regenerate the damaged periodontium. These cells have been identified within adult adipose tissue, periodontal ligament, and palatal tissue. Typical enzymatic isolation protocols are expensive, time consuming and often not clinically compliant. Enzyme-free, mechanical dissociation has been suggested as an alternative method of generating cell suspensions required for cell separation and subsequent expansion ex vivo. In our study, samples of rat skeletal muscle tissue were used to appraise the suitability of a novel mincing method of mechanical dissociation against enzymatic digestion with collagenase and dispase. Skeletal muscle is readily available and has been shown to contain NCSC populations. We used a Rigenera-Human Brain Wave® prototype mincer to produce a suspension of skeletal muscle-derived cells modeling NCSCs. We have compared the resulting cell cultures produced via mechanical dissociation and enzymatic dissociation, producing single cell suspensions suitable for Magnetic Cell Sorting (MACs) and Fluorescence-activated cell sorting (FACS). Despite the Countess Automated Cytometry data demonstrating that cell suspensions produced by mechanical dissociation (n=24) contain on average 26.8 times as many viable cells as enzymatic cell suspensions (n=18), enzymatic suspensions produced more successful cell cultures. Spheroids and subsequently adherent cells formed from 4 enzymatic cell suspensions (44.4%) vs. 1 mechanical cell suspension (8.3%). Enzymatic digestion protocols formed spheroids faster and more plentifully than mechanical cell suspensions. Adherent cells and spheroids isolated via both methods appear morphologically similarly to NCSCs from our previous studies.
ARTICLE | doi:10.20944/preprints201911.0378.v1
Subject: Chemistry And Materials Science, Nanotechnology Keywords: graphene; electrochemical; biosensor; heterostructure; non-enzymatic; schottky diode; glucose; glucometers; ald; pto
Online: 29 November 2019 (11:16:08 CET)
Non-enzymatic glucose sensing is a crucial field of study because of the current market demand. This study proposes a novel design of glucose sensor with enhanced selectivity and sensitivity by using graphene Schottky diodes, which is composed of Graphene/Platinum Oxide/n-Silicon heterostructure. The sensor was tested with different glucose concentrations and interfering solutions to investigate its sensitivity and selectivity. Different structures of the device were studied by adjusting the platinum oxide film thickness to investigate its catalytic activity. It was found that the film thickness plays a significant role in the efficiency of glucose oxidation and hence in overall device sensitivity. Moreover, theoretical investigations were conducted using Density Function Theory (DFT) to better understand the detection method and the origins of selectivity. The working principle of the sensors puts it in a competitive position with other non-enzymatic glucose sensors. DFT calculations provided a qualitative explanation of the charges distributed across the graphene sheet within a system of a platinum substrate with D-glucose molecules above. The proposed graphene/PtO/n-Si heterostructure has proven to satisfy these factors, which opens the door for further developments of more reliable non-enzymatic glucometers for continuous glucose monitoring systems.
ARTICLE | doi:10.20944/preprints201704.0018.v1
Subject: Chemistry And Materials Science, Electrochemistry Keywords: nanomaterials; non-enzymatic glucose biosensors; nanocomposites; electrodeposition; titanium dioxide nanocomposite; XPS; EIS.
Online: 4 April 2017 (09:27:36 CEST)
The performance of modified electrode of nanocomposite film consisting of polypyrrole-chitosan-titanium dioxide (Ppy-CS-TiO2) has been explored as non-enzymatic glucose biosensors. The synergy effect of TiO2 nanoparticles and conducting polymer on the current response of electrode resulted in higher sensitivity for nanocomposite modified electrode. The incorporation of TiO2 nanoparticles in the nanocomposite films were confirmed by XPS spectra. The FESEM and HR-TEM provided more evidences for the presence of TiO2 in Ppy-CS structure. Glucose biosensing properties were determined by amperommetry and cyclic voltammetry (CV) methods. The interfacial properties of nanocomposite electrodes were studied by electrochemical impedance spectroscopy (EIS). The developed biosensors showed a good sensitivity over the liner range of 1-14 mM with a detection limit of 614 μM for glucose. It also exhibited good selectivity and long term stability with no interference effect. The Ppy-CS-TiO2 nanocomposites film presented high electron transfer kinetics.
ARTICLE | doi:10.20944/preprints201608.0072.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: forest residue; pretreatment; liquefaction; enzymatic hydrolysis/saccharification; fermentation; high titer bioethanol; detoxification
Online: 8 August 2016 (10:39:56 CEST)
This study evaluated batch fermentation modes, namely, separate hydrolysis and fermentation (SHF), Quasi-simultaneous saccharification and fermentation (Q-SSF), and simultaneous saccharification and fermentation (SSF), and fermentation conditions, i.e., enzyme and yeast loadings, nutrient supplementation and sterilization, on high titer bioethanol production from SPORL-pretreated Douglas-fir forest residue without detoxification. The result indicated Q-SSF and SSF were obviously superior to SHF operation in terms of ethanol yield. The enzyme loading showed a strong positive correlation between enzyme loading and the ethanol yield. The nutrient supplementation and sterility was not necessary for ethanol production from SPORL-pretreated Douglas-fir. The yeast loading showed no significant influence on the ethanol yield for typical SSF conditions. The terminal ethanol titer of 43.2 g/L, or 75.1% theoretical based on glucose, mannose, and xylose theoretical was achieved when SSF was conducted at the condition of following: whole slurry solids loading of 15%, enzyme loading of 20 FPU/g glucan, 1.8 g/kg (wet) yeast loading, without nutrition supplementation and sterilization, at 38°C, on shake flask at 150 rpm for 96h. It is believed that with mechanical mixing, enzyme loading can be substantially reduced with affect ethanol yield by using a long fermentation time.
ARTICLE | doi:10.20944/preprints202309.0231.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: human hemoglobin; bovine hemoglobin bovine; enzymatic hydrolysis; bioactive peptides; medicine candidate anticancer; Screening
Online: 5 September 2023 (04:38:19 CEST)
Enzymatic hydrolysis of bovine and human hemoglobin yields a diversity of bioactive peptides, some of which are recognized for their antimicrobial properties. Certain small antimicrobial and anticancer peptides target protein synthesis inhibition. This study aims to produce bioactive peptides through enzymatic hemoglobin hydrolysis and evaluate their effects on cell growth inhibition, potentially serving as candidates for biological anticancer drugs. Rapid screening of candidate anticancer peptides derived from enzymatic hydrolysis of bovine and human hemoglobin was conducted using the Lepidium sativum radicle growth technique. The results demonstrate that: 1) the degree of hydrolysis (DH) significantly influences the production of bioactive peptides. DH levels of 3-10% yield considerably stronger radicle growth inhibition compared to DH 0 (native hemoglobin form), exhibiting three to four times greater intensity. 2) Certain peptide fractions from bovine hemoglobin exhibit higher activity than those from human hemoglobin. 3) The structural characteristics of peptides play a crucial role in the observed biological effects. 4) The α137-141 peptide is the most active among the fractions obtained from bovine (IC50 = 29 ± 1 µg/mL) and human hemoglobin (IC50 = 48 ± 2 µg/mL), standing out 10 to 15 times more potent than other hemoglobin fractions. In conclusion, these findings affirm the bioactivity of peptide fractions obtained from bovine and human hemoglobin. The study highlights how enzymatic hydrolysis of bovine and human hemoglobin can yield peptides that inhibit protein synthesis. Ultimately, these results suggest the feasibility of obtaining candidate peptides for biological anticancer drugs from both human and bovine hemoglobin sources. These scientific advances show new hope in the fight against cancer which affects a large number of people around the world.
ARTICLE | doi:10.20944/preprints202306.0699.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: Biological pretreatment; Ligno-hemicellulolytic enzymes; Corn stover; Enzymatic hydrolysis; Pyrenophora phaeocomes S-1
Online: 9 June 2023 (10:28:39 CEST)
Biological pretreatment of lignocellulosic residues has the potential to serve as a sustainable, less energy-intensive alternative to harsh chemical treatments for enhancing cellulose accessibility, despite the requirement of a lengthy incubation period. The study characterized the simultaneous delignification of corn stover by the white-rot fungus Pyrenophora phaeocomes S-1, as well as the co-production of a ligno-hemicellulolytic enzyme cocktail consisting of laccase, xylanase, and mannanase. The maximum yields of all three components of the cocktail were achieved after just 4 days of incubation under solid-state conditions. Following a 40-day fermentation period, we achieved a cellulose recovery of 44.25 ± 1.72%, attributed to the activities of 133.88 U/gds of laccase, 14.93 U/gds of xylanase, and 1.34 U/gds of mannanase co-produced by the fungus in the medium. Subsequently, through the extraction of biologically treated biomass with 0.5N NaOH after 40 days, the cellulose recovery increased to 66.4 ± 1.39%. Enzymatic hydrolysis of the same, employing only 5 FPU/gds of in-house produced cellulases, resulted in the liberation of 397.84 mg/gds of total reducing sugars after 144h. The findings of this study encourage further optimization of biological pretreatment of lignocellulosic residues and enzymatic hydrolysis to enhance the yields of total reducing sugars for their valorization.
ARTICLE | doi:10.20944/preprints201701.0029.v2
Subject: Chemistry And Materials Science, Theoretical Chemistry Keywords: electron transfer; Marcus equation; enzymatic fuel cell; hydrogen oxidation; electrode adsorption; DFT; bioelectrochemistry
Online: 9 January 2017 (02:49:00 CET)
Biohydrogen is a versatile energy carrier for the generation of electric energy from renewable sources. Hydrogenases can be used in enzymatic fuel cells to oxidize dihydrogen. The rate of electron transfer (ET) at the anodic side between the [NiFe]-hydrogenase enzyme distal iron-sulfur cluster and the electrode surface can be described by the Marcus equation. All parameters for the Marcus equation are accessible from DFT calculations. The distal cubane FeS-cluster has a three cysteine and one histidine coordination [Fe4S4](His)(Cys)3 first ligation sphere. The reorganization energy (inner- and outer-sphere) is almost unchanged upon a histidine-to-cysteine substitution. Differences in rates of electron transfer between the wild-type enzyme and the all-cysteine mutant can be rationalized by a diminished electronic coupling between the donor and acceptor molecules in the [Fe4S4](Cys)4 case. The fast and efficient electron transfer from the distal iron-sulfur cluster is realized by a fine-tuned protein environment which facilitates the flow of electrons. This study enables the design and control of electron transfer rates and pathways by protein engineering.
COMMUNICATION | doi:10.20944/preprints202304.0829.v2
Subject: Biology And Life Sciences, Biophysics Keywords: atomic force microscopy; horseradish peroxidase; enzyme aggregation; enzymatic activity; tribo-electric effect; fluid flow
Online: 12 June 2023 (04:15:30 CEST)
Glycerol has found its applications as a heat-transfer fluid in heat exchangers, and as a compo-nent of functional solutions in biosensor analysis. Flowing non-aqueous fluids are known to be able to induce electromagnetic fields due to triboelectric effect. These triboelectrically generated electromagnetic fields can affect biological macromolecules. Horseradish peroxidase (HRP) is widely employed as a convenient model object for studying how external electric, magnetic, and electromagnetic fields affect enzymes. Herein, we have studied whether the flow of glycerol in a ground-shielded cylindrical coil affects the HRP enzyme incubated at a 2 cm distance near the coil’s side. Atomic force microscopy (AFM) has been employed in order to study the effect of glycerol flow on HRP at the nanoscale. Increased aggregation of HRP on mica has been observed after the incubation of the enzyme near the coil. Moreover, the enzymatic activity of HRP has also been affected. The results reported can find their application in biotechnology, food technology and life sciences application, considering the development of triboelectric generators, en-zyme-based biosensors and bioreactors with surface-immobilized enzymes. Our data can also be of interest for scientists studying triboelectric phenomena.
ARTICLE | doi:10.20944/preprints202305.2000.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: Non-enzymatic Detection; Laser-scribed Graphene; Gold Nanostructures; Neutral medium; Disposable sensor; Glucose sensor
Online: 29 May 2023 (08:54:03 CEST)
The authors present a novel sensing platform for a disposable electrochemical, non-enzymatic glucose sensor strip at physiological pH. The sensing material is based on dendritic gold nanostructures (AuNs) resembling feather branches, which are electrodeposited onto a Laser-scribed 3D-Graphene electrode (LSGE). The LSGEs were fabricated via a one-step laser scribing process on a commercially available polyimide sheet. This study investigates several parameters that influence the morphology of the deposited Au nanostructures and the catalytic activity towards glucose electro-oxidation. The electrocatalytic activity of AuNs-LSGE was evaluated using Cyclic Voltammetry (CV), Linear Sweep Voltammetry (LSV), and Amperometry, and was compared to commercially available carbon electrodes prepared under the same electrodeposition conditions. The sensor demonstrated good stability and high selectivity of the amperometric response in the presence of interfering agents, such as ascorbic acid, when a Nafion membrane was applied over the electrode surface. The proposed sensing strategy offers a wide linear detection range, from 0.5 to 20 mM, which covers normal and elevated levels of glucose in the blood, with a detection limit of 0.21 mM. The AuNs-LSGE platform exhibits great potential for use as a disposable glucose sensor strip for point-of-care applications, including self-monitoring and food management. Its non-enzymatic features reduce dependence on enzymes, making it suitable for practical and cost-effective biosensing solutions.
REVIEW | doi:10.20944/preprints202306.0441.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: anti-lipoxygenase peptide; bioactivity; enzymatic hydrolysis; food peptide; food protein; inflammation; lipoxidase; lipoxygenase inhibitory activity.
Online: 6 June 2023 (10:11:09 CEST)
Lipoxygenases are non-heme iron-containing enzymes that catalyze the oxidation of polyunsaturated fatty acids, resulting in the production of lipid hydroperoxides, which are precursors of inflammatory lipid mediators. The enzymes are widely distributed in humans, other eukaryotes, and cyanobacteria. Lipoxygenases hold promise as therapeutic targets for several human diseases, including cancer and inflammation-related disorders. Inhibitors of lipoxygenase have potential applications in pharmaceuticals, cosmetics, and food. Bioactive peptides are short amino acid sequences embedded within parent proteins, which can be released by enzymatic hydrolysis, microbial fermentation, and gastrointestinal digestion. A wide variety of bioactivities have been documented for protein hydrolysates and peptides derived from different biological sources. Recent findings indicate that protein hydrolysates and peptides derived from both edible and non-edible bioresources can act as lipoxygenase inhibitors. In this review, we explore current knowledge on the production of anti-lipoxygenase protein hydrolysates and peptides from millet grains, chia seeds, insects, milk proteins, fish feed, velvet antler blood, fish scales, and feather keratins. We delve into the anti-lipoxygenase activities and modes of action of these protein hydrolysates and peptides, while also highlighting the strengths and shortcomings of previous research. Additionally, we propose potential research directions and areas of improvement that can propel the discovery of anti-lipoxygenase peptides in the near future.
COMMUNICATION | doi:10.20944/preprints201911.0051.v1
Subject: Chemistry And Materials Science, Organic Chemistry Keywords: lactones; lactames; isoindolinones; non-enzymatic biosynthesis; benzophenones; polyketides; reactive natural products; SAHA; aniline, hydroxamic acids
Online: 6 November 2019 (02:53:57 CET)
The structures of recently discovered primarolides A and B suggest their non-enzymatic formation from a common 2-formylbenzophenone precursor. This hypothesis is based on the experimentally proven facile conversion of pestalone (also a 2-formyl-benzophenone) either into the isomeric lactone pestalalactone or the structurally related isoindolinone pestalachloride A. In a related fashion, the racemic isoindolinone natural product mariline A is supposed to biosynthetically originate from the corresponding keto-aldehyde and an aniline, as experimentally supported by model studies. Due to the close structural relationship with known systems, it appears highly probable that primarolides A and B were generated under the fermentation conditions from a massarinin-related 2-formylbenzophenone (proprimarolide) by reaction either with aniline or a nucleophilic catalyst, respectively. Suberoylanilide hydroxamic acid (SAHA), used as an additive during the fermentation, is supposed to act both as a source of aniline and as a nucleophilic catalyst.
REVIEW | doi:10.20944/preprints201810.0251.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: EGFET; ISFET; electrochemical cell; enzymatic biosensor; DNA–DNA biosensor; immunosensor; antigen–antibody biosensor; ionic sensor
Online: 12 October 2018 (04:38:42 CEST)
Since 1970s, a great deal of attention has been paid to the development of semiconductor–based biosensors because of the numerous advantages they offer, including high sensitivity, faster response time, miniaturization, and low–cost manufacturing for quick biospecific analysis with reusable features. Commercial biosensors have become highly desirable in the fields of medicine, food, environmental monitoring as well as military applications (e.g., Hoffmann–La Roche, Abbott Point of Care, Orion High technologies, etc.), whereas increasing concerns on the food safety and health issues have resulted in the introduction of novel legislative standards for these sensors. Numerous devices have been developed for monitoring of biological–processes such as nucleic–acid hybridization, protein–protein interaction, antigen–antibody bonds and substrate–enzyme reactions, just to name a few. Since 1980s scientific interest moved to the development of semiconductor–based devices which also include integrated front–end electronics, such as the extended–gate–field–effect–transistor biosensor which is one of the first miniaturized chemical sensors. This work is intended to be a review of the state of the art focused on the development of biosensors based extended–gate–field–effect–transistor within the field of bioanalytical applications, which will highlight the most recent research works reported in the literature. Moreover, a comparison among the diverse EGFET devices will be presented giving particular attention to the materials and technologies.
REVIEW | doi:10.20944/preprints202007.0459.v1
Subject: Chemistry And Materials Science, Electrochemistry Keywords: current-potential curve; multi-enzymatic cascades; multi-analyte detection; mass-transfer-controlled amperometric response; potentiometric coulometry
Online: 20 July 2020 (08:16:47 CEST)
Bioelectrocatalysis provides the intrinsic catalytic-functions of redox enzymes to non-specific electrode reactions and is the most important and basic concept for biosensors. This review starts by describing fundamental characteristics of bioelectrocatalytic reactions in mediated and direct electron transfer types from a theoretical viewpoint and summarizes amperometric biosensors based on multi-enzymatic cascades and for multi-analyte detection. The review also introduces prospective aspects of two new concepts of biosensors: mass-transfer-controlled (pseudo)steady-state amperometry at microelectrodes with enhanced enzymatic activity without calibration curves and potentiometric coulometry at enzyme/mediator-immobilized biosensors for absolute determination.
REVIEW | doi:10.20944/preprints202105.0419.v1
Subject: Engineering, Industrial And Manufacturing Engineering Keywords: Microgel; Janus particle; ionotropic gelation; crosslinking; cell encapsulation; enzymatic cross-linking; photopolymerization; hierarchical microgels; composite microgels; microfluidics.
Online: 18 May 2021 (11:05:01 CEST)
This article provides a systematic review of the crosslinking strategies used to produce microgel particles in microfluidic chips. Various ionic crosslinking methods for gelation of charged pol-ymers are discussed, including external gelation via crosslinkers dissolved or dispersed in the oil phase, internal gelation methods using crosslinkers added to the dispersed phase in their non-active forms, such as chelating agents, photo-acid generators, sparingly soluble or slowly hydrolyzing compounds, and methods involving competitive ligand exchange, rapid mixing of polymer and crosslinking streams, and merging polymer and crosslinker droplets. Covalent crosslinking methods using enzymatic oxidation of modified biopolymers, photo-polymerization of crosslinkable monomers or polymers, and thiol-ene “click” reactions are also discussed, as well as the methods based on sol-gel transitions of stimuli responsive polymers triggered by pH or temperature change. In addition to homogeneous microgel particles, the production of structurally heterogeneous particles such as composite hydrogel particles entrapping droplet interface bi-layers, core-shell particles, organoids, and Janus particles are also discussed. Microfluidics offers the ability to precisely tune chemical composition, size, shape, surface morphology, and internal structure of microgels by bringing in contact multiple fluid streams in a highly controlled fashion using versatile channel geometries and flow configurations and allowing controlled crosslinking.
REVIEW | doi:10.20944/preprints202111.0138.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: spontaneous; non-enzymatic; post translational modifications; racemization; biological clock; natural selection; allostatic load; psychological aging; psychological stress; stress response sys-tem; phase transitions.
Online: 8 November 2021 (13:08:58 CET)
In humans, age-associated degrading changes are observed in molecular and cellular processes underly the time-dependent decline in spatial navigation, time perception, cognitive and psy-chological abilities, and memory. Cross talk of biological, cognitive, and psychological clocks provides an integrative contribution to healthy and advanced aging. At the molecular level, ge-nome, proteome, and lipidome instability are widely recognized as the primary causal factors in aging. We narrow attention to the roles of protein aging linked to prevalent amino acids chirali-ty, enzymatic and spontaneous (non-enzymatic) post-translational modifications (PTMs SP), and non-equilibrium phase transitions. The homochirality of protein synthesis, resulting in the steady-state non-equilibrium condition of protein structure, makes them prone to multiple types of enzymatic and spontaneous PTMs, including racemization and isomerization. Spontaneous racemization leads to the loss of the balanced prevalent chirality. Advanced biological aging re-lated to irreversible PTMs SP has been associated with the nontrivial interplay between poor so-matic and mental health conditions. Through stress response systems (SRS), the environmental and psychological stressors contribute to the age-associated “collapse” of protein homochirality. The role of prevalent protein chirality and entropy of protein folding in biological aging is mainly overlooked. In a more generalized context, the time-dependent shift from enzymatic to the non-enzymatic transformation of biochirality might represent an important and yet un-der-appreciated hallmark of aging.
ARTICLE | doi:10.20944/preprints201812.0126.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: advanced glycation end products (AGEs); enzymatic hydrolysis; glycation; methylglyoxal-derived hydroimidazolone 1 (MG-H1); seeds; seed ageing; seed quality; sodium dodecyl sulfate (SDS)
Online: 11 December 2018 (10:40:15 CET)
Seeds represent the major source of food protein, impacting on both human nutrition and animal feeding. Therefore, seed quality needs to be appropriately addressed in the context of viability and food safety. Indeed, long-term and inappropriate storage of seeds might result in enhancement of protein glycation, which might affect their quality and longevity. Glycation of seed proteins can be probed by exhaustive acid hydrolysis and quantification of the glycation adduct Nɛ-(carboxymethyl)lysine (CML) by liquid chromatography-mass spectrometry (LC-MS). This approach, however, does not allow analysis of thermally and chemically labile glycation adducts, like glyoxal-, methylglyoxal- and 3-deoxyglucosone-derived hydroimidazolones. Although enzymatic hydrolysis might be a good solution in this context, it requires aqueous conditions, which cannot ensure reconstitution of seed protein isolates. Because of this, the complete profiles of seed AGEs are not characterized so far. Therefore, here we propose the approach, giving access to quantitative solubilization of seed proteins in presence of sodium dodecyl sulfate (SDS) and their quantitative enzymatic hydrolysis prior to removal of SDS by reversed phase solid phase extraction (RP-SPE). Using MG-H1 as a case example, we demonstrate the applicability of this method for reliable and sensitive LC-MS-based quantification of chemically labile AGEs and its compatibility with bioassays.