Search Results (333)

Soil salinization critically threatens global agricultural productivity by impairing plant growth and soil fertility. This study investigated the potential of a consortium, comprising Acinetobacter calcoaceticus DP25, Staphylococcus epidermidis DP28, and Enterobacter hormaechei DP29, to enhance the saline–alkali tolerance of alfalfa and improve soil properties. The experiments comprised five germination treatments (saline control, each strain alone, consortium) and three pot treatments (non-saline control, saline control, consortium). Under saline–alkali stress, co-inoculation with the consortium significantly (p < 0.05) increased alfalfa seed germination rates, emergence rates, and biomass (shoot and root dry weight), while promoting root development. Physiological analyses revealed that the bacterial consortium mitigated stress-induced damage by enhancing photosynthetic efficiency, chlorophyll content, and antioxidant enzyme activities (superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)), while decreasing malondialdehyde (MDA) levels. Moreover, the inoculant improved osmoprotectant accumulation (soluble sugars, soluble proteins, and proline) and modulated soil properties by reducing pH and electrical conductivity (EC), while elevating nutrient availability and soil enzyme activities. Correlation and principal component analyses (PCA) confirmed strong associations among improved plant growth, physiological traits, and soil health. These findings demonstrate that the bacterial consortium effectively alleviates saline–alkali stress in alfalfa by improving soil health, offering a sustainable strategy for ecological restoration and improving agricultural productivity in saline–alkali regions. Full article

Heavy metal (HM) contamination represents a significant threat to soil functionality and ecosystem health. The present study aims to assess the efficacy of an integrated bioremediation strategy combining Lavandula angustifolia (lavender) and a four-strain bacterial consortium in restoring a multi-contaminated soil collected from a former industrial site in Southern Italy. Microcosm experiments were conducted over a period of 90 days, including three treatments and a control: a planted condition (PLANT), a bioaugmented condition (BIOAUG), and a combined plant and bioaugmentation condition (PLANT+BIOAUG). The control (HCS) consisted of unplanted and non-bioaugmented soil. Soil physico-chemical parameters (e.g., pH, electrical conductivity, and heavy metal concentrations), plant growth, microbial abundance, and dehydrogenase activity (DHA) were measured at the initial and final experimental time. Finally, a Soil Quality Index (SQI) was applied. The combined treatment (PLANT+BIOAUG) promoted a significant reduction in total Pb and Sn concentrations by 44.7% and 66.9%, respectively. Moreover, a significant increase in soil pH and microbial abundance was observed. Applying the SQI to integrate overall soil data made it possible to highlight the highest quality score (0.73) for this condition. These findings suggest the potential effectiveness of lavender-assisted bioaugmentation as a scalable and multifunctional strategy for remediating heavy metal-contaminated soils, in line with ecological restoration principles. Full article

The bacterial phylum Verrucomicrobiota accommodates free-living and symbiotic microorganisms, which inhabit a wide range of environments and specialize in polysaccharide degradation. Due to difficulties in cultivation, much of the currently available knowledge about these bacteria originated from cultivation-independent studies. A phylogenetic clade defined by the free-living bacterium from oilsands tailings pond, Oleiharenicola alkalitolerans, and the symbiont of the tunicate Lissoclinum sp., Candidatus Didemniditutus mandelae, is a poorly studied verrucomicrobial group. This clade includes two dozen methagenome-assembled genomes (MAGs) retrieved from aquatic and soil habitats all over the world. A new member of this clade, strain Vm1, was isolated from a methane-fed laboratory bioreactor with a Methylococcus-dominated methane-oxidizing consortium and characterized in this study. Strain Vm1 was represented by ultra-small, motile cocci with a mean diameter of 0.4 µm that grew in oxic and micro-oxic conditions at temperatures between 20 and 42 °C. Stable development of strain Vm1 in a co-culture with Methylococcus was due to the ability to utilize organic acids excreted by the methanotroph and its exopolysaccharides. The finished genome of strain Vm1 was 4.8 Mb in size and contained about 4200 predicted protein-coding sequences, including a wide repertoire of CAZyme-encoding genes. Among these CAZymes, two proteins presumably responsible for xylan and arabinan degradation, were encoded in several MAGs of Vm1-related free-living verrucomicrobia, thus offering an insight into the reasons behind wide distribution of these bacteria in the environment. Apparently, many representatives of the Oleiharenicola–Candidatus Didemniditutus clade may occur in nature in trophic associations with methanotrophic bacteria, thus participating in the cycling of methane-derived carbon. Full article

The yield of corn straw is huge, and returning straw to the field is an efficient utilization measure. The challenge in this approach is how to efficiently degrade the straw returned to the field. The study of efficient straw-degrading bacteria and their application conditions is an important approach. Therefore, after enrichment, separation, screening, and strain identification, three strains (X−2, X−4, and X−6) of highly efficient cellulose-degrading bacteria were obtained, namely Pseudomonas aeruginosa PA14, Brevibacillus parabrevis M3, and Bacillus cereus PgBE247. Based on antagonistic experiment results in which the strains were observed to not be antagonistic to each other, they were combined to prepare a bacterial consortium (M−1) for straw degradation. The CMCase, FPA, and β-Gase of the M−1 consortium were 28.46 U/mL, 30.93 U/mL, and 27.94 U/mL, respectively, higher than the values for single bacteria. On the 35th day, the degradation rate of corn straw by M−1 reached 79.81% in liquid medium, significantly increased by 72.06% (p < 0.01) compared to the sterile control (CK), and was significantly higher than single bacteria (p < 0.05). The straw degradation rate of M−1 was the highest at 69.69% in the simulated straw return, significantly increased by 59.84% compared to CK (p < 0.05), and increased by 18.32%, 11.59%, and 14.92% compared to the straw degradation rates of X−2, X−4, and X−6, respectively. The response surface condition optimization verification results showed that the straw degradation rate was 72.15 ± 1.21% when the amount of bacterial suspension was 25%, corn straw dosage was 9 g, initial pH was 7, and reaction temperature was 30 °C. Overall, this study revealed a new bacterial consortium for corn straw decomposition and optimized the conditions for its return to the field, providing a theoretical basis for subsequent studies. Full article

Biotechnological research increasingly focuses on developing new drugs to counter the rise of antibiotic-resistant strains in hospitals. This study aimed to create bacterial lysates from antibiotic-resistant pathogens isolated from patients and medical instruments across hospital departments. Identification was performed based on morphological, cultural, and biochemical characteristics, as well as 16S rRNA gene sequencing using the BLAST algorithm. Strain viability was assessed using the Miles and Misra method, while sensitivity to eight antibacterial drug groups and biosafety between cultures were evaluated using agar diffusion. From 15 clinical sources, 25 pure isolates were obtained, and their phenotypic and genotypic properties were studied. Carbohydrate fermentation testing confirmed that the isolates belonged to the genera Escherichia, Citrobacter, Klebsiella, Acinetobacter, Pseudomonas, Staphylococcus, Haemophilus, and Streptococcus. The cultures exhibited good viability (10⁹–10¹⁰ CFU/mL) and compatibility with each other. Based on prevalence and clinical significance, three predominant hospital pathogens (Klebsiella pneumoniae 12 BL, Pseudomonas aeruginosa 3 BL, and Acinetobacter baumannii 24 BL) were selected to develop a bacterial lysate consortium. Lysates were prepared with physical disruption using a French press homogenizer. The resulting product holds industrial value and may stimulate the immune system to combat respiratory pathogens prevalent in Kazakhstan’s healthcare settings. Full article

Sustainable agriculture requires replacing agrochemicals with environmentally friendly products. One alternative is bacterial inoculants with plant-growth-promoting (PGP) activity. Bacterial consortia offer advantages over single-strain inoculants, as they possess more PGP traits and allow the exploitation of bacterial synergies. Synthetic bacterial communities (SynComs) can be used as inoculants that are thoroughly characterized and assessed for efficiency and safety. Here, we describe the construction of a SynCom composed of seven bacterial strains isolated from the rhizosphere of tomato plants and other orchard vegetables. The strains were identified by 16S rDNA sequencing as Pseudomonas spp. (two isolates), Rhizobium sp., Ensifer sp., Microbacterium sp., Agromyces sp., and Chryseobacterium sp. The metagenome of the combined strains was sequenced, allowing the identification of PGP traits and the assembly of their individual genomes. These traits included nutrient mobilization, phytostimulation, and biocontrol. When inoculated into tomato plants in an agricultural soil, the SynCom caused minor effects in soil and rhizosphere bacterial communities. However, it had a high impact on the gene expression pattern of tomato plants. These effects were more significant at the systemic than at the local level, indicating a priming effect in the plant, as signaling through jasmonic acid and ethylene appeared to be altered. Full article

The excessive use of chemical fertilizers in tea cultivation threatens soil health, environmental sustainability, and long-term crop productivity. This study explores the application of plant growth-promoting bacteria (PGPB) as an eco-friendly alternative to conventional fertilizers. A bacterial consortium was developed using selected rhizobacterial isolates—Lysinibacillus fusiformis, five strains of Serratia marcescens, and two Bacillus spp.—based on their phosphate and zinc solubilization abilities and production of ACC deaminase, indole-3-acetic acid, and siderophores. The consortium was tested in both pot and field conditions using two tea clones, S3A3 and TS491, and compared with a chemical fertilizer treatment. Plants treated with the consortium showed enhanced growth, biomass, and antioxidant activity. The total phenolic contents increased to 1643.6 mg GAE/mL (S3A3) and 1646.93 mg GAE/mL (TS491), with higher catalase (458.17–458.74 U/g/min), glutathione (34.67–42.67 µmol/gfw), and superoxide dismutase (679.85–552.28 units/gfw/s) activities. A soil metagenomic analysis revealed increased microbial diversity and the enrichment of phyla, including Acidobacteria, Proteobacteria, Actinobacteria, Chloroflexi, and Firmicutes. Functional gene analysis showed the increased abundance of genes for siderophore biosynthesis, glutathione and nitrogen metabolism, and indole alkaloid biosynthesis. This study recommends the potential of a PGPB consortium as a sustainable alternative to chemical fertilizers, enhancing both the tea plant performance and soil microbial health. Full article

Petroleum-contaminated soil is an increasingly severe environmental issue. The integration of phytoremediation and microbial remediation can effectively mitigate their individual limitations and enhance remediation efficiency. In this study, four newly isolated bacterial strains (including Cytobacillus and Rhodococcus) that exhibited preferential degradation of distinct petroleum components were combined with the rhamnolipid-producing strain Pseudomonas aeruginosa SL-1. The immobilization of this petroleum-degrading microbial consortium was performed by biochar adsorption and sodium alginate embedding, subsequently optimized using response surface methodology (0.75 g·L⁻¹ of biochar, 40 g·L⁻¹ of sodium alginate, and 40 g·L⁻¹ of calcium chloride). The results showed that the highest petroleum degradation rate (97.1%) of immobilized bacterial consortium was achieved at 72 h at a petroleum concentration of 5.0 g·L⁻¹. When combined with Sudan grass for soil bioremediation, the degradation rate reached 72.8% after 120 d for soil containing 5.0 g·kg⁻¹ of petroleum, higher than the results for the treatments with only immobilized bacterial consortium (53.0%) or Sudan grass (49.2%). Furthermore, significant improvements were observed for soil pH; nitrogen, phosphorus, and potassium contents; and urease, dehydrogenase, and catalase activities. Composite treatment also significantly increased the diversity and richness of the soil bacterial community and regulated its structure, function, and network composition. This study offers theoretical insights and potential practical applications for the enhanced bioremediation of petroleum-contaminated soils. Full article

Soil contamination with petroleum hydrocarbons is a serious environmental issue, necessitating the development of effective and environmentally friendly remediation methods that align with the principles of sustainable development. This study investigated the impact of selected biosurfactants on the efficiency of the biodegradation of total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAHs) in contaminated soil. Six biosurfactants—poly-γ-glutamic acid (γ-PGA), rhamnolipid, surfactin, a mixture of γ-PGA, rhamnolipids, and surfactin (PSR), as well as two commercial formulations (JBR 425 and JBR 320)—were evaluated in combination with a bacterial consortium. Biodegradation experiments were conducted under laboratory conditions for a 90-day period. The effectiveness of the tested biosurfactants was assessed using respirometric analysis, the chromatographic determination of the residual hydrocarbon content, and toxicity assays. The results showed that the application of a bacterial consortium enriched with a mixture of biosurfactants PSR (a biosurfactant concentration in the inoculating mixture: 5 g/dm³) was the most effective approach, resulting in an oxygen uptake of 5164.8 mgO₂/dm³ after 90 days, with TPH and PAH degradation rates of 77.3% and 70.32%, respectively. Phytotoxicity values decreased significantly, with TU values ranging from 6.32 to 4.62 (growth inhibition) and 3.77 to 4.13 (germination). Toxicity also decreased in the ostracodtoxkit test (TU = 4.35) and the Microtox SPT test (TU = 4.91). Among the tested biosurfactants, surfactin showed the least improvement in its bioremediation efficiency. Under the same concentration as in the PSR mixture, the oxygen uptake was 3446.7 mgO₂/dm³, with TPH and PAH degradation rates of 60.64% and 52.64%, respectively. In the system inoculated with the bacterial consortium alone (without biosurfactants), the biodegradation efficiency reached 44.35% for TPH and 36.97% for PAHs. The results demonstrate that biosurfactants can significantly enhance the biodegradation of petroleum hydrocarbons in soil, supporting their potential application in sustainable bioremediation strategies. Full article

This study evaluated the efficacy of acclimated cow manure as a seed microbiome to enhance food waste hydrolysis. Anaerobic hydrolysis was performed on simulated food waste in a hydrolytic–acidogenic leach bed reactor (LBR) operated in batch mode under mesophilic conditions (35 °C) for 16 days. The acclimation process involved three sequential runs: Run-1 utilized 20% (w/w) cow manure as seed, Run-2 employed the digestate from Run-1 (day 5), and Run-3 used the digestate from Run-1 (day 10). Run-3 achieved 70.4% removal of volatile solids (VSs), surpassing Run-1 (47.1%) and Run-2 (57.1%). Compared with the first run, the production of chemical oxygen demand (COD) and total soluble products (TSPs) increased by 48.7% and 75.9%, respectively, in Run-3. The hydrolysis rate of proteins was 48.4% in Run-1, while an increase of 16.9% was achieved in Run-3 with the acclimatized consortium. A molecular analysis of the microbial community existing in the reactors of Run-2 and Run-3 indicated that the improvement in process performance was closely related to the selection and enrichment of specific hydrolytic–acidogenic bacteria in the reactor. A functional analysis showed that the gene copy numbers for pyruvate synthesis and fatty acid synthesis and metabolism pathways were higher in all bacterial species in Run-3 compared to in those of the other two runs, indicating improved capacity through acclimation in Run-3. The experimental results demonstrate that the hydrolysis of food waste can be enhanced through the acclimation of seed microbes from cow manure. Full article

Microalgal–bacterial consortia are the environmentally sustainable biotechnological strategy to enhance the potential of microalgae. Understanding the regulatory mechanisms that enable bacteria to adapt to culture conditions of each bioprocess is crucial to ensure a successful synergic interaction. Thus, the present study evaluated the transcriptomic response of microalgal growth-promoting bacteria (MGPB) A. brasilense separately co-cultured with both green microalgae Scenedesmus sp. and Chlorella sorokiniana during CO₂ fixation from biogas through a microarray-based approach. The transcriptome profiling revealed a total of 416 differentially expressed genes (DEGs) in A. brasilense: 228 (140 upregulated and 88 downregulated) interacting with Scenedesmus sp. and 188 (40 upregulated and 148 downregulated) associated with C. sorokiniana. These results support the modulation of signal molecules: indole-3-acetic acid (IAA), riboflavin, and biotin, during co-cultivation with both microalgae. The findings suggest that the metabolic A. brasilense adaptation was mainly favored during the mutualistic interaction with Scenedesmus sp. Finally, a valuable contribution is provided to the biotechnological potential of the microalga–Azospirillum consortium as an environmentally sustainable strategy to improve the bio-refinery capacity of these microalgae and biogas upgrading by valorizing CO₂ of these gaseous effluent. Full article

Inflammatory bowel disease (IBD) is a chronic relapsing inflammatory condition of the gastrointestinal tract. It is generally accepted that IBD is characterized by an inappropriate immune response to the intestinal microbiome in genetically susceptible individuals. Despite the available treatment options ranging from salicylates and corticosteroids, to immunosuppressants and biologics, there is still a high unmet medical need for patients who respond poorly to drugs or are not able to tolerate them. Microbiome-based therapeutics offer a valid treatment strategy for IBD with enhanced safety. A butyrate-producing consortium of six commensal strains (MH002) was evaluated in a series of in vitro, ex vivo, and in vivo experiments mimicking multiple IBD-related dysfunctions, namely disrupted intestinal permeability and immune activation. MH002 rapidly produced high levels of butyrate in fed-batch cultures, and significantly increased butyrate levels within one day after administration to IBD-derived gut microbial communities in vitro. Both in Caco-2/peripheral blood mononuclear cells (PBMCs) co-cultures, and IBD patients-derived organoids and colonic explants, MH002 reduced inflammation and restored epithelial barrier integrity. In addition, MH002 promoted wound repair in vitro. Finally, MH002 protected mice and rats from chemically induced colitis. Altogether, results showed that MH002 presents a novel therapeutic avenue for the treatment of IBD. Full article

The bioavailability of heavy metals is profoundly influenced by their interactions with active soil components (microorganisms, organic matter, and iron minerals). However, the effects of urease-producing bacteria combined with organo-Fe hydroxide coprecipitates (OFCs) on Cd accumulation in wheat, as well as the mechanisms underlying these effects, remain unclear. In this study, pot experiments integrated with high-throughput sequencing were employed to investigate the impacts of the urease-producing bacterial strain TJ6, ferrihydrite (Fh), and OFCs on Cd enrichment in wheat grains, alongside the underlying soil–microbial mechanisms. The results demonstrate that the strain TJ6-Fh/OFC consortium significantly (p < 0.05) reduced (50.1–66.7%) the bioavailable Cd content in rhizosphere soil while increasing residual Cd fractions, thereby decreasing (77.4%) Cd accumulation in grains. The combined amendments elevated rhizosphere pH (7.35), iron oxide content, and electrical conductivity while reducing (14.5–21.1%) dissolved organic carbon levels. These changes enhanced soil-colloid-mediated Cd immobilization and reduced Cd mobility. Notably, the NH₄⁺ content and NH₄⁺/NO₃⁻ ratio were significantly (p < 0.05) increased, attributed to the ureolytic activity of TJ6, which concurrently alkalinized the soil and inhibited Cd uptake via competitive ion channel interactions. Furthermore, the relative abundance of functional bacterial taxa (Proteobacteria, Gemmatimonadota, Enterobacter, Rhodanobacter, Massilia, Nocardioides, and Arthrobacter) was markedly increased in the rhizosphere soil. These microbes exhibited enhanced abilities to produce extracellular polymeric substances, induce phosphate precipitation, facilitate biosorption, and promote nutrient (C/N) cycling, synergizing with the amendments to immobilize Cd. This study for the first time analyzed the effect and soil science mechanism of urease-producing bacteria combined with OFCs in blocking wheat’s absorption of Cd. Moreover, this study provides foundational insights and a practical framework for the remediation of Cd-contaminated wheat fields through microbial–organic–mineral collaborative strategies. Full article

Acute oak decline (AOD) is a multifactorial disease that affects European oaks and represents a growing threat to forests. The disease results from a complex interaction between biotic and abiotic factors: the various environmental stresses, which vary depending on the area in question, and generally increased by climate change, predispose trees to attack by opportunistic pathogens. Among them, we focused on a bacterial consortium associated with AOD, consisting mainly of Brenneria goodwinii, Gibbsiella quercinecans, Rahnella victoriana, and Lonsdalea britannica, which produce degrading enzymes that contribute to phloem necrosis and the development of stem bleeds and bark cracks. However, the role of other pathogens, such as fungi, cannot be ruled out, but instead could be contributory. The potential involvement of xylophagous insects is also being studied, particularly Agrilus biguttatus, which, although, frequently associated with the disease, has not been conclusively demonstrated to act as an active vector of the bacteria. Currently, disease management requires integrated approaches, including monitoring and other forestry strategies to increase forest resilience. Given the phenomenon’s complexity and the risk of the future expansion of that bacterial consortium, further research is necessary to understand the dynamics and to develop effective containment strategies of AOD-associated bacteria. Full article

The vinasse from Agave americana L. (blue cabuya) liquor has a high concentration of organic matter, nutrients with high chemical oxygen demand (COD), and low pH, properties that give it the potential to generate adverse impact on the environment if improperly disposed of. In other countries, studies have been conducted on yeast strain combinations in vinasses to produce biomass and reduce organic load, but there are no studies of the aforementioned yeast consortium in blue cabuya liqueur vinasses to produce biomass and reduce COD. Given this problem, the objective of the research was to reduce this adverse environmental impact through aerobic fermentation of this vinasse with the yeast consortium Candida utilis, Kluyveromyces marxianus and Saccharomyces cerevisiae (D 47-Lalvin). As a result, biomass production and COD reduction were achieved. The study evaluated temperature variables of 28 °C, 30 °C, and 32 °C, and pH values of 3, 4, and 5 under conditions of consortium and nutrient diammonium phosphate (DAP) concentrations of 1.32 g/L and 1.5 g/L, respectively, in a bioreactor with automatic control of temperature, time, stirring speed of 100 RPM, and air flow of 1 VVM. The result was a biomass yield of 93.4% and a COD reduction of 33.3%. It is concluded that the aerobic fermentation process of blue cabuya liquor vinasse with the yeast consortium employed produces a high biomass yield, which can be used for its protein value as an animal feed supplement and, due to its low COD value, as an agricultural fertilizer. Full article