A replicated outdoor pot experiment was conducted in order to investigate the effect of different phytohormone and siderophore producing, and P-solubilizing bacterial species on spinach nu-trient uptake, nitrate concentration and nitrate reductase activity. The mentioned parameters were determined in spinach leaves (Spinacia oleracea L.), non-inoculated and inoculated with four plant growth–promoting actinobacteria (Streptomyces griseus (S1), Streptomyces albogriseolus (S2), Strep-tomyces aurantiacus (S3) and Streptomyces kanamyceticus (S4) under the influence of two sources of nitrogen fertilizers including potassium nitrate and urea (100 and 200 ppm). Inoculation with the strains increased spinach shoot fresh weight by 16%–43% over the control. Bacterial inoculation gave leaf chlorophyll increases of 15%–40%. Inoculation increased plant height by 2.2%–24.6% in spinach. A close reverse relationship between nitrate concentration and enzyme activity (r2= 0.87) was demonstrated. The measured parameter responses were variable and dependent on the in-oculant strain, with highest enzyme activity and lowest nitrate concentration exhibited in S2 (S. albogriseolus) inoculation. The source and application dose of nitrogen fertilizer had varied impact on measured parameter. The maximum phosphorous and iron concentration were measured by soil inoculation with S4 and applying 200 ppm nitrate potassium nitrogen fertilizer. Application of 200 ppm KNO3 nitrogen fertilizer with different Streptomyces strains showed the capability of S2 in decreasing nitrate content while protein content increased. In particular, the strains S2 and S4 have great potential in being formulated and used as biofertilizers.

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.

In this research, we isolated and characterized Streptomyces strains, endemic from sugar beet fields of the Beni-Mellal region, able to use natural rock phosphate (RP) and tricalcium phosphate (TCP), as sole phosphate source. Ten Streptomyces isolates yielded a comparable biomass in the presence of these two insoluble phosphate sources, indicating that they were able to extract similar amount of phosphorus (P) from the latter for their own growth. Interestingly, five strains released soluble P in large excess from TCP in their culture broth whereas only two strains, BP, related to Streptomyces bellus and BYC, related to Streptomyces enissocaesilis, released a higher or similar amount of soluble P from RP than from TCP, respectively. This indicated that the rate of P released from these insoluble phosphate sources exceeded its consumption rate for bacterial growth and that most strains solubilized TCP more efficiently than RP. Preliminary results suggested that the solubilization process of BYC, the most efficient RP and TCP solubilizing strain, involves both acidification of the medium and excretion of siderophores. Actinomycete strains possessing such interesting RP solubilizing abilities may constitute a novel kind of intrans beneficial for plant nutrition and more environmentally friendly than chemical fertilizers in current use.

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

Plant growth-promoting rhizobacteria (PGPR) are beneficial bacteria that play a crucial role in sustainable agriculture by enhancing plant growth through various mechanisms. This review examines the contributions of PGPR in improving nutrient availability, producing phytohormones, providing biocontrol against pathogens, and enhancing abiotic stress tolerance. By reducing the necessity for chemical fertilizers and pesticides, PGPR mitigate environmental impacts, enhance soil health, and support long-term agricultural productivity. However, challenges such as inconsistent performance across various soils, regulatory barriers, and limited farmer awareness hinder their widespread adoption. Recent advancements in nano-encapsulation technology, genetic engineering, and bioinformatics present promising solutions for overcoming these obstacles and enhancing PGPR efficacy. The incorporation of PGPR into biofertilizers, biopesticides, and integrated pest management (IPM) strategies offers a sustainable resolution to global agricultural challenges. This review addresses the current state of PGPR research, applications, and future directions for optimizing their use in promoting sustainable agriculture.

The biodegradability of water hyacinth for biogas and biofertiliser production was studied under mesophilic conditions. The effects of water hyacinth pre-treatments were also included in this investigation. It was found that water hyacinth has a low biodegradability of 27% when monodigested while at a 3:1 ratio with cow manure, the biodegradability increases to 46%. At this elevated biodegradability, the water hyacinth biomethane potential was 185 LCH4/kgVS, while that of cow manure was 216 LCH4/kgVS. The Gompertz kinetic model had superior parameters than the Logistic model for most of the water hyacinth-cow manure combined substrate digestion. Based on the Gompertz model, the lag phase and daily maximum methane production rate were 5.5 days and 22.9 ml /day respectively for the 3:1 codigestion (R2 of 0.99). These values were 6.7 days and 15.2 ml/day respectively, in the case of water hyacinth monodigestion (R2 = 0.996). The dominant microbial species detected in the digestates were Bacteroidetes and Proteobacteria. A few microbial species were indigenous to water hyacinth but a more diverse consortia which is key to efficient substrate biodegradation, came from cow manure. The digestate contained ammonium nitrogen at 68 mg/kg with phosphorous and potassium at 73 and 424 mg/kg respectively. Nitrogen was lower but phosphorous and pottasium were comparable to previously studied digestates of other substrates. Only water hyacinth pretreated through aerobic composting proved to unlock a higher methane yield that matched a 3:1 codigestion with cow manure. Other pretreatments induced better biodegradation performance than that observed on untreated water hyacinth but this improvements were not as good as that of the 3:1 codigestion scheme. It was concluded that water hyacinth sourced from the Hartbeespoort dam, could be treated through anaerobic digestion to recover biogas and biofertilizer. However, more experiments are required to fully understand and harness the optimisation opportunities available in applying this technology to manage water hyacinth.

As environmental and health concerns increase, the trend of sustainable agriculture moves toward using biological agents. About 60% of all biological fungicides have Trichoderma species as the active ingredient, with T. harzianum as the most common species in these products. However, the name T. harzianum has often been incorrectly used in culture collections, databases, and the scientific literature due to the division of the Harzianum Complex Clade (HCC) into more than 95 cryptic species with only one being named T. harzianum. In this study, 49 strains previously identified as T. harzianum in three surveys of Trichoderma species from soils in South and Central America were re-identified using phylogenetic analyses based on tef1α, rpb2, and ITS loci and were combined with the corresponding species in two other studies, where the species were correctly identified. Based on the results of the five surveys of the total 148 strains in HCC, 11 species were identified and T. afroharzianum, T. lentiforme, T. endophyticum followed by T. azedevio and T. harzianum were detected as the dominant species of the HCC in South and Central America. This is the first report of identifying dominant Trichoderma species within the HCC in South and Central American soil based on multiple studies, which will be useful in selecting strains within the complex clade for formulation of biocontrol and biofertilizer products in the continent.

As environmental and health concerns increase, the trend of sustainable agriculture moves toward using biological agents. About 60% of all biological fungicides have Trichoderma species as the active ingredient, with T. harzianum as the most common species in these products. However, the name T. harzianum has often been incorrectly used in culture collections, databases, and the scientific literature due to the division of the Harzianum Complex Clade (HCC) into more than 95 cryptic species with only one being named T. harzianum. In this study, strains previously identified as T. harzianum in three surveys of Trichoderma species from soils in South and Central America were reanalyzed using phylogeny based on tef1α, rpb2, and ITS loci and combined with the corresponding species in two other studies, where the species were correctly identified. Based on the results of the five surveys, T. afroharzianum, T. lentiforme, T. endophyticum followed by T. azedevio and T. harzianum were found to be the dominant species of the HCC in South and Central America. This is the first report of identifying dominant Trichoderma species within the HCC in South and Central American soil based on multiple studies, which will be useful in selecting strains within the complex clade for formulation of biocontrol and biofertilizer products in the continent.

Certain Trichoderma isolates provide biofertilizer, biocontrol, and other plant-beneficial activities while inhabiting the soil or internal plant issues; and their use in agricultural systems could contribute to sustainable food production. It is thought that this colonization of soil and internal plant tissues is fundamental for biocontrol and biofertilizer applications. Our collective analyses of prior surveys, where the tef1 sequence was almost exclusively used to identify Trichoderma species, showed that isolates from the Harzianum Complex Clade, the T. asperellum/T. asperelloides group, T. virens, T. hamatum, and T. atroviride were prevalent in soil and/or as endophytes. Population structure and genetic diversity of these species were investigated, and new lineages with geo-graphic significance within T. atroviride, T. asperellum, T. hamatum, and T. virens populations were found. The nearest relatives of some species were also revealed. Choosing isolates from among more than 500 known Trichoderma species for use in non-targeted evaluation screens for biocontrol or biofertilizer applications is time-consuming and expensive. Preferentially selecting species from T. atroviride, T. asperellum/T. asperelloides, T. hamatum, species from the T. harzianum Complex Clade, T. virens, and possibly nearest relatives, may speed the identification of candidates for commercialization due to the demonstrated ability of these species to successfully inhabit the soil and endorhizosphere. To our knowledge, this is the first report where dominant soil- and en-dophyte-inhabiting Trichoderma species were identified from past survey data and population structure and genetic diversity analyses conducted.

Declining agricultural productivity caused by soil salinization are becoming global dilemmas in recent years. Biofertilizers show great potential as a sustainable and environmentally friendly fertilization strategy for soil improvement, but their effectiveness for saline soil amendment and improving plant growth under saline stress is not well understood. Assess the effectiveness of biofertilizers in improving saline soils and enhancing crop growth under saline stress, as well as investigate its related potential mechanisms. Changes in soil physico-chemical properties, plant physiological parameters and soil microbial communities were analyzed through pot experiments. The results showed that the application of biofertilizer reduced total soluble salts (TSS) in soil by 30.8% and increased the Brassica rapa L. biomass by 8.4 times. Biofertilizer application increased soil organic matter (SOM), total nitrogen (TN) and available phosphorus (AP). Biofertilizer applications also increased the SOD, CAT, chl.a, chl.b, total soluble sugars, and Proline content. Biofertilizers present plant growth promotion and potential pathogenic fungi reduction by increasing the abundance of Bacillus and Planococcus and decreasing the abundance of Mortierella and Aspergillus. Overall, the results of this study demonstrated the excellent efficacy of biofertilizers in improving saline soils, and the application of biofertilizer strategies will greatly promote agricultural production.

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