Search Results (1,179)

Plant growth-promoting microorganisms (PGPMs) and microbial biocontrol agents have emerged as key tools for improving crop productivity while maintaining environmental sustainability. However, central questions remain regarding which factors determine their consistent field performance and how these factors interact under real agronomic conditions. Previous research has demonstrated that PGPMs enhance nutrient acquisition, regulate phytohormone balance, improve stress tolerance, and suppress plant pathogens through diverse biochemical and ecological mechanisms. Advances in omics technologies, genome mining, and synthetic microbial communities have further expanded understanding of their functional potential. Nevertheless, many studies rely on laboratory-scale experiments or short-term trials, with limited multi-season and cross-regional validation. This gap contributes to inconsistent field outcomes and restricts large-scale agricultural adoption. Long-term multi-season validation and reproducibility assessment remain essential priorities for improving reliability of microbial agricultural products. This review synthesizes recent advances in PGPM-based biofertilizers and microbial biocontrol technologies, critically examining their mechanisms of action, scalability constraints, formulation challenges, and regulatory limitations. It identifies major translational barriers, including context dependency, mechanistic uncertainties, reproducibility gaps, and insufficient systems-level integration. Full article

With rising global pressures on resources and the environment, transitioning out of our traditional linear agricultural models is long overdue. By itself, circular agriculture seeks to close loops for nutrients, but it also has a future that is constrained by the fragmentation of process integration, lack of system integration and optimization, and poor adaptive decision-making under the often very variable circumstances of agricultural systems. Microalgae are a versatile photosynthetic platform with unique value in this context. They can recover key nutrients (nitrogen, phosphorus and carbon) from agricultural wastes simultaneously and also convert these vital nutrients into multipurpose biomass. Here, this review synthesizes the multifunction of microalgae towards sustainable agriculture, with a particular emphasis on nutrient recycling and the use of whole microalgal biomass. Downstream applications are manifold, ranging from agricultural outputs, such as biofertilizers and biostimulants, to different products of high value (HVPs). Realizing this potential requires practical challenges to be addressed in integrated system design, coupling and scaling up. AI-assisted modelling and optimization have already started emerging as important tools for this purpose. Reliable system optimization relies on defining objective functions and balancing resource recovery efficiency and economic output, which in turn enables robust multi-objective decision-making. Concluding this review, we propose a holistic vision from a central integral biorefinery concept. Our framework clearly demonstrates how to fully enhance competitiveness, sustainability and scalability of microalgae-based agricultural systems through co-integrated high-value utilization and nutrient cycling. Full article

Saline–alkali soils suffer from severe deficiencies in available phosphorus, and externally added phosphorus is readily immobilized by metal ions in the soil. Therefore, activating inorganic phosphorus in the soil represents a significant challenge. In this study, 35 salt–alkali-tolerant bacteria were isolated from rhizosphere soils (pH 9.20–9.68). Three phosphate-solubilizing strains (HA2, HPA5, and KA1) capable of growing under severe saline–alkali stress conditions (pH 10, 5% NaCl) and possessing multiple plant growth-promoting traits (nitrogen fixation, potassium solubilization, siderophore production, and IAA secretion) were screened and co-cultured to form the microbial consortium HHK. It was hypothesized that this consortium might exhibit synergistic effects, resulting in significantly higher phosphorus solubilization capacity compared to individual strains. The results showed that under saline–alkali stress, the phosphate solubilization capacity of HHK (484.59 ± 15.79 mg/L) was significantly higher than that of any single strain (285.59 ± 12.60 mg/L). Non-targeted metabolomics and enzyme assays indicated that HHK solubilizes P via organic acids (e.g., citric, L-malic acid) and synergistically modulates core metabolic pathways, including ABC transport, TCA cycle, and glycolysis, alleviating oxidative damage and maintaining cellular homeostasis. Short-term soil incubation confirmed that HHK significantly increased available phosphorus (53.67%) and soil fertility, indicating its potential as a biofertilizer. Full article

Data-driven approaches are increasingly required to optimize biofertilization strategies in forage systems. Machine learning (ML) provides an efficient tool for identifying functional drivers in complex plant–soil–microbe systems, offering important perspectives for precision data-driven agriculture. However, despite its potential, ML remains data-driven in studies involving diazotrophic inoculation using biochar as a pelletizing material, particularly in forage grasses. This study applied ML to predict the key drivers controlling Brachiaria brizantha performance and soil quality under biochar-pelletized diazotrophic bacteria (DB). Five isolates were inoculated with or without biochar, and plant traits and soil attributes, including pH, potassium, phosphorus, sodium, and urease activity were evaluated. These data were integrated into multivariate analyses and ML algorithms, including Linear Discriminant Analysis, Random Forest, and Support Vector Machine, to identify the functional drivers that best discriminate treatment performance and uncover mechanistic functional drivers. All isolates increased soil potassium content, with the highest values in the biochar amended treatments, and a 39% increase. Soil pH and urease activity were significantly modulated by isolate identity, while biomass allocation patterns differed among treatments. Overall, the results highlight that biochar pelletization can enhance the effectiveness of DB inoculants. ML revealed that dry foliar biomass, soil pH, and fresh root weight were the most predictive variables, highlighting consistent signatures explaining plant–soil responses to biochar-pelletized DB. These findings demonstrate that interpretable ML can disentangle complex plant–soil–microbe interactions, support precision biofertilization design, and serve as an efficient decision-support tool for sustainable pasture management. Beyond the present system, this study establishes a transferable and scalable analytical framework for precision biofertilization strategies in forage systems and other biochar-mediated agroecosystems, advancing predictive and data-driven approaches in sustainable agricultural engineering. Full article

Baby maize (Zea mays L.) is a high-value horticultural crop widely cultivated due to its short growth cycle and strong market demand. However, intensive production systems often rely heavily on chemical fertilizers, leading to reduced nutrient use efficiency and potential soil degradation. The present study investigated the potential of the Priestia megaterium Thr45 to enhance soil fertility, improve crop performance, and optimize fertilizer management in baby maize cultivation. A field experiment was conducted using a three-factor factorial design consisting of bacterial inoculation, different urea application rates, and different KCl rates. Soil chemical properties, plant growth parameters, yield components, and nutrient composition of edible cobs were evaluated. The results showed that inoculation with P. megaterium Thr45 significantly increased available phosphorus and exchangeable potassium in soil compared with the non-inoculated control. Inoculated plants exhibited higher chlorophyll content, greater leaf development, and increased plant height during early growth stages. Bacterial inoculation also significantly improved yield components, including ear number, ear yield, edible cob yield, and plant biomass. Furthermore, the nutritional quality of baby corn was enhanced, as reflected by increased protein and mineral (N, P, and K) concentrations in edible cobs. Significant interactions between bacterial inoculation and fertilizer treatments indicated that the beneficial effects of P. megaterium Thr45 were closely associated with nutrient management practices. Notably, comparable yield and nutritional quality were achieved under reduced nitrogen and potassium fertilizer inputs when combined with bacterial inoculation. These findings highlight the novel potential of P. megaterium Thr45 as an effective biofertilizer for improving nutrient availability, maintaining high productivity, and supporting sustainable baby maize production with reduced chemical fertilizer inputs Full article

Saline irrigation water is increasingly used in arid and coastal regions, posing serious constraints to soil health and wheat yield, particularly in saline–sodic soils. A two-season field experiment was conducted to evaluate the effects of compost, biofertilizers (Azospirillum brasilense and Azotobacter chroococcum), and their combinations on soil physicochemical properties, microbial activity, wheat growth, yield, and physiological traits under two irrigation water salinity levels (3 and 6 dS m⁻¹). Two wheat varieties differing in salt tolerance (Miser 4 and Sakha 95) were tested. Salinity significantly increased soil EC and ESP and reduced plant growth, yield, and nutrient content, while integrated bio-organic treatments markedly alleviated these adverse effects. Compost combined with Azotobacter chroococcum markedly improved soil physical conditions, enhanced microbial biomass carbon, reduced sodicity indicators, and promoted wheat productivity across both seasons. Multivariate analyses including principal component analysis (PCA), redundancy analysis (RDA), and self-organizing maps (SOMs) revealed a strong positive association between yield traits, microbial activity, and soil fertility, and negative correlations with salinity stress indicators. The results demonstrate that combining compost with biofertilizers induces both immediate and residual improvements in saline–sodic soils, enhances wheat resilience to salinity stress, and offers a sustainable approach for improving cereal production under salt-affected environments. Full article

The recurrent influx of pelagic Sargassum spp. along Caribbean coastlines poses a significant environmental challenge while offering potential as a resource-recovery agricultural input. However, agricultural reuse of Sargassum biomass raises concerns regarding salinity and trace-metal distribution within the soil–plant–food continuum. This study evaluated the short-term elemental response to a Sargassum-Based Liquid Biofertilizer (SBLB) produced via controlled anaerobic fermentation, using tomato (Solanum lycopersicum L.) grown under greenhouse conditions. Raw biomass, fermented biofertilizer, irrigation water, soils, vegetative tissues, and fruits were chemically characterized. Elemental concentrations were quantified by ICP–OES and ICP-MS and treatment effects were analyzed using one-way and two-way ANOVA (p < 0.05). Anaerobic fermentation resulted in lower measured concentrations of sodium, arsenic, and selected trace elements in the liquid fraction relative to raw biomass. SBLB application increased soil macronutrient availability (N, P, K, Ca, Mg), while soil trace-metal concentrations remained within international reference ranges during the experimental period. Metals of concern (As, Cd, Pb, Ni, Cr) showed no detectable short-term enrichment in soils, vegetative tissues, or fruits relative to controls. In tomato fruits, arsenic, cadmium, and lead were below the limit of quantification across all treatments. Within the experimental timeframe, SBLB application was not associated with detectable trace-element accumulation in the soil–plant system. Long-term field studies and detailed soil physicochemical characterization are required to evaluate cumulative effects under repeated applications. Full article

Rhizosphere nitrogen-fixing bacteria play a critical role in sustainable crop production by enhancing nitrogen availability and improving soil fertility. This study aimed to isolate and characterize native rhizospheric nitrogen-fixing bacteria (NRNFB) associated with baby maize (Zea mays L.) roots and evaluate their nitrogen-fixing potential. Thirty root samples were collected, and ten bacterial isolates (V1–V10) were obtained using selective media. Morphological, biochemical, and physiological analyses identified strain V3 as the most promising candidate, exhibiting strong growth on nitrogen-free Burk medium and high oxidase, catalase, and urea hydrolysis activities. The strain demonstrated broad environmental tolerance, including salinity up to 4% NaCl, temperatures ranging from 15 to 45 °C, and pH values between 5.0 and 8.0. Molecular identification based on 16S rRNA gene sequencing revealed 100% sequence similarity with Peribacillus simplex LT4 (strain LT4). Nitrogenase activity analysis showed a peak during the exponential growth phase, accompanied by increased nitrogen accumulation in the culture medium, confirming active biological nitrogen fixation. These findings highlight the physiological adaptability and functional efficiency of strain LT4, supporting its potential development as a biofertilizer for sustainable maize production systems. Full article

Human hair waste represents a dense nitrogen reservoir (~15% N); however, its agricultural valorization is hindered by two concurrent barriers: the extreme recalcitrance of alpha-keratin and the high salinity derived from cosmetic treatments. While chemical hydrolysis generates secondary pollutants, biological composting often fails due to osmotic inhibition of non-adapted inoculants. Here, we report a biological strategy to circumvent this osmotic bottleneck using unwashed human hair collected from professional salons. We compared the degradation efficiency of a syntrophic Effective Microorganisms (EM) consortium with traditional single-strain inoculants (Trichoderma spp. and Bacillus spp.) in a 16-week co-composting system. Data revealed that the EM consortium displayed superior resilience, sustaining thermophilic sanitation (>45 °C) compliant with US EPA PFRP standards and achieving a Nitrogen Mineralization Rate of 883 mg N kg⁻¹ week⁻¹ (nearly triple the control), resulting in a final N content of 1.41% (14,133 mg kg⁻¹). Crucially, the EM treatment reduced electrical conductivity from a phytotoxic 7.23 mS cm⁻¹ to a tolerable level of 3.82 mS cm⁻¹, a mitigation effect likely mediated by humification-driven ion chelation. This performance suggests a “syntrophic succession” mechanism where initial acidification facilitates subsequent proteolytic attack. The final product presented a high sulfur-to-nitrogen ratio indicative of extensive disulfide bond cleavage. Preliminary economic estimates (~$60 USD ton⁻¹) confirm the process’s viability for decentralized scalability, though future molecular validation is recommended. We conclude that bio-augmentation with metabolically diverse consortia is essential to process chemically treated hair waste, converting a hazardous salon residue into a high-value proteinaceous biofertilizer. Full article

Sustainable food production systems based on the use of biofertilizers and soil improvers are proposed to mitigate agricultural-related environmental impacts and address the climate crisis. In particular, plant growth-promoting microbes (PGPM) and biochar (Char) have been reported to improve plant growth, soil quality, and crop yield; however, their effects on food quality remain debated. In this study, untargeted metabolomics based on ultra-high performance liquid chromatography–ion mobility–high-resolution mass spectrometry (UHPLC-IMS-HRMS) and proton nuclear magnetic resonance spectroscopy (¹H-NMR) are proposed to achieve a comprehensive investigation of the effects of Char, PGPM and Char+PGPM on durum wheat. A total of 88 metabolites were annotated by UHPLC-IMS-HRMS, mainly belonging to carbohydrates, flavones, flavonoids, glycerophospholipids, and glycolipids, while 30 compounds were annotated by ¹H-NMR, mostly amino acids and short-chain carboxylic acids. The two datasets were merged with the gluten protein content dataset by using low- and mid-level data fusion approaches, obtaining models that exhibit excellent classification performance. Integrated analysis highlighted that the combined Char+PGPM treatment induced metabolic changes across multiple chemical classes, including enrichment of flavonoids and lipids, and downregulation of carbohydrate metabolites, suggesting a redistribution of carbon resources and modulation of secondary metabolism with potential implications on wheat grain quality. Full article

Due to their exceptional nutritional benefits, microalgae and cyanobacteria are recognized as sustainable food sources and key contributors to the circular bioeconomy. Arthrospira sp. has garnered significant attention as one of the most promising cyanobacteria for a wide range of applications. The purpose of this study is to systematically analyze and synthesize global research trends in Arthrospira sp. applications. In this context, a “systematic review” refers to an integrated bibliometric and thematic analysis encompassing publication trends, geographical distribution of research outputs, leading journals, key application sectors, market development, and associated challenges and future prospects. Consequently, extensive research has been conducted on this species, leading to diverse areas of interest and application. This review article is the first of its kind, offering a comprehensive summary of trends in Arthrospira sp. applications over the past 15 years. It presents a bibliometric analysis of publications from 2010 to 2024 in journals indexed by Scopus. The analysis revealed that Bioresource Technology is the leading journal in publishing related research, with China producing the highest number of studies. Furthermore, phycocyanin extraction emerged as the most frequently studied application. Recently explored applications include its use as a biofertilizer, in bioplastic production, and in cosmetics. The Arthrospira sp. market is currently valued at an estimated $619 million in 2024, positioning it as a dominant player in the global industry. However, challenges persist, including safety concerns related to potential allergies and toxicity, as well as regulatory hurdles that may affect commercialization and market expansion. Full article

Lactic acid bacteria (LAB) are non-spore-forming, non-respiring, Gram-positive cocci or rods that produce lactic acid through carbohydrate fermentation. They are widely used in food and dairy production as probiotics, biofertilizers, and as sources of industrially valuable exopolysaccharides. Growing evidence indicates that many of these functional properties are regulated by quorum sensing (QS), a cell–cell communication mechanism that coordinates bacterial behavior in response to population density. This review summarizes current knowledge on the role of QS in regulating key physiological and functional traits of LAB, including biofilm formation, stress adaptation, metabolite production, and host interactions. Additionally, it highlights the ability of LAB-derived molecules to interfere with QS systems of pathogenic bacteria, contributing to pathogen control. Overall, this review emphasizes QS as a key regulatory mechanism underlying the technological and probiotic potential of LAB, with important implications for food, health, and biotechnological applications. Full article

Microbial biofertilizers offer a sustainable alternative to reduce inorganic fertilizer inputs in intensive vegetable production. While rhizobia are traditionally associated with legumes, their co-inoculation with native rhizobacteria for non-leguminous crops like tomatoes remains under-explored. This study aimed to isolate native rhizobacteria compatible with Bradyrhizobium diazoefficiens NE1-65 and evaluate their combined effect on the tomato plant (var. max F1) under reduced inorganic fertilizer rates. From the initial eighteen isolates screened on nitrogen-free media, and solubilization assays of phosphorus and potassium, three isolates (RM-8, RM-17, RM-18) were found compatible with B. diazoefficiens NE1-65. Isolate RM-17 (tentatively identified as Aureimonas sp. based on 16S rRNA gene sequence) was selected for its high K-solubilizing capacity (KSI = 8.60). Then, a 90-day growth trial compared various fertilizer application rates (0, 25, 50, 75, and 100%) with and without the bacterial consortia. The 75% fertilizer rate plus the consortia significantly outperformed the 100% fertilizer rate alone. Specifically, it increased plant height (11.57%), fruit diameter (9.23%), fruit number (53.90%), and fruit weight (16.15%). These findings demonstrate that the RM-17 and B. diazoefficiens NE1-65 consortia can partially substitute inorganic fertilizers while significantly enhancing tomato growth and yield, highlighting its potential application for sustainable tomato production systems. Full article

The increasing reliance on chemical fertilizers has raised environmental concerns and highlighted the need for sustainable alternatives. This study aimed to (i) optimize the carrier-to-substrate ratios and moisture content during composting with potassium-solubilizing purple nonsulfur bacteria (K-PNSB) and (ii) evaluate the growth-promoting effect of the optimized biofertilizer on maize seedlings. Three K-PNSB strains (Cereibacter sphaeroides M-Sl-09, Rhodopseudomonas thermotolerans M-So-11, and Rhodopseudomonas palustris M-So-14) were used. Composting experiments were conducted using different carrier-to-substrate ratios and moisture levels with K-PNSB inoculation. Compost quality was assessed through nutrient dynamics, bacterial density, and physicochemical properties over four weeks. The results showed that the 1:1:3 substrate ratio combined with 50–60% moisture content consistently enhanced K solubilization, bacterial survival, and compost maturity indicators. Application of the optimized biofertilizer improved maize growth traits compared with the non-inoculated control. These findings demonstrate that controlling material ratios and moisture content improves compost quality and plant growth performance, providing a sustainable alternative to chemical fertilizers. This study provides a practical framework for developing sustainable K-solubilizing biofertilizers from agricultural residues. Full article