Search Results (2,464)

Aflatoxin B₁ (AFB₁) is a highly stable mycotoxin that can persist during conventional food processing and therefore poses a serious risk to food and feed safety. In this study, two enzymes (CotA and Prx) were heterologously expressed in Bacillus subtilis, purified by Ni–NTA affinity chromatography, and evaluated for their ability to degrade AFB₁. Both enzymes exhibited remarkable thermostability and distinct catalytic optima. CotA exhibited its highest activity at 80 °C with an AFB₁ removal of 38.4%, whereas Prx showed its highest activity at 90 °C with a removal of 82.6%. The optimal pH values were near neutral, with CotA performing best at pH 7.0 and Prx at pH 7.5, and both reactions approached maximal conversion within approximately 10 h. When the two enzymes were combined, a clear cooperative effect was observed. The mixed system achieved 91.0% AFB₁ removal at 80 °C after 10 h, with the best degradation activity occurring at a CotA to Prx ratio of 1:3. At 50 °C, neither enzyme alone caused appreciable AFB₁ degradation, but the addition of hydrogen peroxide markedly enhanced catalytic activity. Both enzymes also retained substantial activity after boiling and autoclaving. In a maize flour model, the mixed-enzyme system showed strong AFB₁ degradation capacity, and peroxide-assisted treatment further improved activity. These results establish a thermostable and peroxide-responsive enzymatic platform for AFB₁ degradation and support future development of enzyme-based detoxification strategies for food and feed applications. Product identification and toxicological validation will be needed to confirm the safety of the treated products. Full article

Mungbean (Vigna radiata) is an important cash crop, yet the production is significantly compromised by continuous cropping. Beneficial microbial inoculation offers a promising strategy to alleviate the stresses through rhizosphere modulation and host physiological reprogramming. This study evaluated the efficacy of two biological control agents, Bacillus subtilis (B. subtilis) and Trichoderma harzianum (T. harzianum), in promoting mungbean growth under continuous-cropping conditions. Both individual applications of B. subtilis and T. harzianum significantly improved plant biomass, root system architecture, and yield. Combined metagenomic and transcriptomic analyses were conducted to unravel the underlying mechanisms. According to metagenomic analysis, both B. subtilis and T. harzianum were responsible for significant changes in beta diversity without significantly affecting the alpha diversity of the rhizosphere microbial community. T. harzianum recruited Chitinophagaceae unclassified, Abditibacterium, Hydrogenophilaceae unclassified, Methylophilaceae unclassified, and Chimaeribacter, while Bs recruited Candidatus Saccharibacteria unclassified. Transcriptomic analysis indicated that T. harzianum induced more extensive transcriptional reprogramming than B. subtilis. The enrichment analysis revealed both shared and distinct responses triggered by the two treatments. These findings suggest that B. subtilis and T. harzianum alleviate continuous-cropping stress through distinct yet complementary mechanisms involving rhizosphere microbiome modulation and mungbean transcriptional reprogramming. This study provides a sustainable strategy for legume cultivation. Full article

Efficient cultivation is essential for the rose industry. Both substrate formulation and plant growth-promoting rhizobacteria (PGPR) application both critical, yet their synergistic effects remain limited. This study investigated the synergistic effects of Bacillus subtilis (Bs) and Priestia megaterium (Pm) combined with five substrate formulations on the growth physiology, photosynthetic characteristics, and soil properties of Rosa × hybrida ‘Ruby’. Two-way ANOVA revealed significant interactions between substrate and PGPR treatments for most growth and physiological indicators. Orthogonal experiments demonstrated that specific PGPR–substrate combinations significantly enhanced plant growth and photosynthetic performance of the studied cultivar, as well as soil quality. Principal component analysis and membership function analysis identified four substrate–PGPR combinations as optimal, with the T4 substrate (humus/perlite/vermiculite/coconut coir/peat/biochar = 5:1.5:1:1:1:0.5) showing the most pronounced effects. In this T4 substrate, PGPR inoculation significantly altered the rhizobacterial community structure. LEfSe analysis revealed 67 enriched microbial biomarkers—substantially more than single-strain treatments. The relative abundance of beneficial genera such as Acidibacter and Chryseotalea increased, and the combined bacterial treatment enhanced functional pathways associated with signal transduction, cell motility, and RNA processing. Compared to single-strain treatments, the combined bacterial application demonstrated superior regulatory effects on plant growth. The optimal combined treatments increased plant height by up to 42.7%, root activity by 103.0%, soluble protein content by 302.8%, and soil ammonium nitrogen by 168.8%. These findings demonstrated that tailored combinations of PGPR and cultivation substrates highlight the potential for optimizing rose cultivation and improving the rhizosphere microecological environment. Full article

Probiotics are commonly applied to maintain the balance of gut microbiota and regulate the intestinal metabolic function of companion animals. In the present study, complex probiotics (Bacillus coagulans SNZ-1969, Bacillus subtilis, and Bacillus licheniformis) were added into the basal diet of domestic cats to investigate their influence on the intestinal microbiome and metabolic characteristics. Results revealed that the alpha diversity of the gut microbiota in the probiotic group was enhanced when compared to the control group. The beta diversity of the gut microbiota was also altered by the oral consumption of the complex probiotics. Compared to the control group, the relative abundance of beneficial microbes (such as Clostridium, Bacteroides, Phocaeicola, and Ruminococcus) in the probiotic group was enhanced, while the relative abundance of opportunistic pathogens (such as Escherichia, Gallibacter, Corynebacterium) was decreased. Additionally, the intestinal metabolic characteristics of domestic cats were also changed. The metabolomic analysis identified 408 differential metabolites between the two groups, and the KEGG function pathway analysis proved that the dominant pathway related to the differential metabolites were the amino acid metabolism, lipid metabolism, carbohydrate metabolism, energy metabolism, endocrine system, digestive system, immune system, and other metabolic pathways. Spearman’s correlation analysis revealed that the beneficial microbes had positive correlations with the differential metabolites. In conclusion, the current study demonstrated that oral administration of complex probiotics could regulate overall health and well-being in domestic cats through modulating the gut microbiome and metabolic characteristics. Full article

Municipal wastewater represents an underutilized secondary biomass resource rich in organic carbon and nutrients that can be valorized through biotechnological conversion. In this study, we developed an integrated multi-microbial biorefinery platform to transform municipal wastewater into value-added biofuel via sequential bacterial treatment, microalgal biomass generation, and fungal-assisted harvesting. Wastewater was first pretreated with Bacillus subtilis to enzymatically hydrolyze complex organic substrates and enrich the medium with bioactive metabolites, including auxins and gibberellins. The conditioned wastewater was subsequently used to cultivate Chlorella vulgaris, followed by biomass recovery using Trichoderma viride pellets as a sustainable bioflocculant. The integrated consortium significantly enhanced nutrient removal efficiency and promoted algal biomass accumulation, lipid enrichment, and biodiesel productivity compared to monoculture controls. Elevated hydrolytic enzyme activities (cellulase, protease, and amylases) facilitated organic matter conversion into bioavailable substrates, while increased phytohormone levels stimulated algal growth and lipid biosynthesis. Additionally, fungal bioflocculation substantially improved biomass recovery efficiency, reducing the need for energy-intensive harvesting technologies. This work highlights the potential of a biotechnology-driven approach for integrating wastewater remediation with biofuel production. By integrating microbial metabolism, enzymatic transformation, and sustainable separation processes, the proposed biorefinery system suggests a potentially low-carbon approach for simultaneous environmental remediation and biomass valorization, although further life cycle and energy balance analyses are required to validate this aspect. Full article

Bioactive glass (BAG) S53P4 is a clinically approved bone substitute with antibacterial, osteoconductive and osteostimulatory properties. Its antibacterial effect is associated with ion release, local pH elevation and osmolality, but the precise biochemical and biophysical mode-of-action is unclear. This study investigates the antibacterial mechanism of BAG S53P4 eluates. BAG eluates, collected at 2, 4, 8, and 24 h, eradicated Staphylococcus aureus. Elemental analysis revealed an early increase in concentrations of Si and Na, a later rise in Ca, depletion of P over time and rapid loss of Mg. Membrane disturbances occurred within 5 min, evident by permeability for SYTOX, aligning with time-kill kinetics for S. aureus and Bacillus subtilis. In B. subtilis, 2h-BAG-eluate induced rapid delocalization of marker proteins for cell division and DNA repair, signaling membrane potential collapse and nucleoid condensation. Transcriptomics revealed early transcription remodeling reflecting ionic and energetic imbalance, including disruption of central metabolism, redox homeostasis, and translational stability. Scanning electron microscopy revealed severe cell surface damage and particulate deposits on S. aureus. Transmission electron microscopy showed cell envelop disruptions and cytoplasmic leakage. Energy dispersive X-ray analysis identified Si on bacterial cell surface at 4 h and intracellular accumulation in punctured, empty cells at 24 h. Overall, BAG ionic dissolution products kill bacteria through a stepwise mechanism involving membrane damage, protein delocalization and metabolic impairment, accompanied by Si deposition on bacterial surfaces and loss of Mg. This finally leads to cell wall degradation, cytoplasmic content leakage and further Si deposition on the cells and inside cell ghosts. Full article

In the sustainability framework, valorization of organic by-products as reservoirs of phytochemicals useful for human health represents a hot topic. Therefore, this study evaluated Norway spruce bark and twigs (NSB, NST), chestnut tree wood (CTW), and pomegranate fruit waste/pomace (PFW) as sources of bioactive compounds by employing green technologies. Microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE), applied individually or sequentially, were optimized by modulating solvent composition, temperature, time, microwave power, and ultrasound amplitude. Hydroalcoholic extraction (50% ethanol) combined with MAE yielded the highest phenolic recovery and antioxidant activity across all matrices. PFW exhibited the highest antioxidant activity assessed through FRAP, ORAC, and DPPH assays. Phytochemical profiling by HPLC-DAD identified stilbenes in spruce extracts, ellagic acid in chestnut wood, and ellagic acid and punicalagins in pomegranate waste as major bioactive constituents. Additionally, NSB and PFW exhibited α-amylase inhibitory activity. Antimicrobial testing demonstrated dose-dependent activity against Gram-positive (Staphylococcus epidermidis and Bacillus subtilis) and Gram-negative (Pseudomonas stutzeri) strains, with PFW exhibiting the strongest inhibition and NSB displaying broad-spectrum effects. Total phenolic content changed moderately after 21 days of storage. These results demonstrate that sustainable extraction enables efficient recovery of bioactive compounds from plant by-products, supporting their further functional, dietary, and medicinal applications. Full article

Muskmelon (Cucumis melo L.) is an economically important crop that remains highly susceptible to destructive fungal diseases, including gummy stem blight, downy mildew, Fusarium wilt, and anthracnose. Although fungicides and resistant cultivars are widely used, reliance on chemical control raises concerns regarding environmental safety, food quality, and the emergence of fungicide-resistant pathogen populations. Consequently, microbial biopesticides, particularly Bacillus species, have attracted increasing attention as sustainable alternatives. In this study, muskmelon plants exhibiting leaf wilting, chlorosis, and stem yellowing were collected from Guangming Farm in Wufeng, Taichung, Taiwan, and associated pathogens were isolated from stem tissues and identified to determine the causal agent of these symptoms. In addition, the biocontrol efficacy of Bacillus subtilis strain MCLB2 against melon fruit rot, as well as its underlying mechanisms, was evaluated. Pathogenicity assays confirmed that isolate F01 was the causal agent. Based on morphological characteristics and internal transcribed spacer (ITS) sequence analysis, this isolate showed 99.8% identity to Fusarium pernambucanum URM 7559 (GenBank accession no. NR_163754), and phylogenetic analysis further placed it within the Fusarium incarnatum–equiseti species complex (FIESC). Antagonistic assays demonstrated that B. subtilis MCLB2 significantly inhibited mycelial growth and suppressed the spore germination of F. pernambucanum. In addition, culture filtrates of strain MCLB2 effectively reduced Fusarium-induced fruit rot in melon and disrupted fungal cellular respiration. Liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis revealed that the strain produced surfactin-family lipopeptides. In conclusion, B. subtilis MCLB2 exhibits potential as a sustainable biocontrol agent for managing Fusarium fruit rot in melon, likely through surfactin-mediated disruption of fungal cellular respiration. Full article

Bacillus and Paenibacillus species are common and widely distributed microorganisms in food systems, often implicated in food spoilage and quality issues. Bacillus subtilis, in particular, has been associated with gas production and package bulging in seasoned foods. In this study, we developed a rapid and visual detection method for Bacillus subtilis by integrating (Recombinase Polymerase Amplification) RPA with (Clustered Regularly Interspaced Short Palindromic Repeats) CRISPR/Cas12a technology (designated as RPA-CRISPR/Cas12a). Specific RPA primers and probes were designed based on the conserved gyrB gene of Bacillus subtilis. Two sets of crRNA were designed according to the number of T-rich PAM sites on the RPA-amplified target sequence, and the reaction conditions were optimized in combination with the CRISPR/Cas12a trans-cleavage detection technology. Under optimized conditions, the crRNA3 guide (with a TT-rich PAM site) demonstrated superior cleavage efficiency compared to crRNA2 (TTT-rich PAM), while crRNA1 (TTTT-rich PAM) showed no activity. The assay achieved a detection limit of 150 pg/μL for genomic DNA and 5.5 CFU/mL for bacterial suspensions within 10 min at 37 °C. The method exhibited high specificity and sensitivity, providing a robust tool for early and on-site detection of Bacillus subtilis in food products. Full article

Mango (Mangifera indica L.), a major tropical fruit crop, suffers severe anthracnose damage caused by Colletotrichum spp., and traditional chemical control has environmental and food safety risks, with plant-microbe interaction-based biological control as a sustainable alternative. However, the regulatory role of phyllosphere microbiota in the tripartite interactions among mango, beneficial microbes and Colletotrichum remains unclear. This study explored phyllosphere microbiota’s function in mango resistance to Colletotrichum and clarified the biocontrol mechanism of key beneficial isolates. We found Colletotrichum infection significantly reshaped mango leaf endophytic and epiphytic microbial communities, enriching Burkholderia, Acinetobacter, Bacillus and other dominant genera. We isolated a B. subtilis strain L-1 from the epiphytic microbiota that was 18-fold enriched in Colletotrichum-infected mango leaves. This strain exhibited potent antagonistic activity against Colletotrichum siamense with a relative inhibition rate of 82.10%, and delivered 79.77% biocontrol efficacy on mango leaves via two synergistic pathways: inhibiting pathogen spore germination and penetration by producing antimicrobial secreted metabolites and volatile organic compounds, and enhancing host disease resistance. Our findings advance the understanding of plant-phyllosphere microbiota-pathogen tripartite interactions and provide elite microbial resources for sustainable anthracnose management. Full article

Green synthesis is an eco-friendly, simple, and cost-effective process for the synthesis of metal nanoparticles from plant extracts that are rich in bioactive compounds. In the current study, the antioxidant potential and total soluble polyphenol content (TPC) of different parts of Ligusticum mutellina (L.) Crantz were evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing antioxidant power) assays, and the results indicated that the seed extract was the most active plant part. HPLC analysis indicated the presence of phenolic compounds such as gallic acid, protocatechuic acid, and catechin, which may contribute to the reduction and stabilization of AgNPs. Silver nanoparticles (AgNPs) were synthesized from the aqueous seed extract of L. mutellina. The formation of nanoparticles was confirmed by UV–Vis spectroscopy, FT-IR analysis, powder X-ray diffraction (PXRD), and transmission electron microscopy (TEM). The UV–Vis spectrum indicated a surface plasmon resonance peak at around 411 nm, and PXRD analysis indicated an average crystallite size of around 13 nm. TEM analysis revealed predominantly spherical nanoparticles with an average size of 25.36 ± 10.76 nm. The synthesized AgNPs exhibited strong antibacterial activity against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. Overall, the results demonstrate that L. mutellina seed extract represents an effective natural source of reducing and stabilizing agents for green nanoparticle synthesis and highlight the potential of the obtained AgNPs as environmentally friendly antimicrobial materials. Full article

Background: Salmonella enterica subsp. enterica serovar Gallinarum biovar Pullorum (Salmonella Pullorum) is a specific avian pathogen responsible for Pullorum disease, causing substantial economic losses to the global poultry industry. With the rising restrictions on antibiotic use, probiotics have emerged as promising therapeutic alternatives. The Bacillus subtilis group, including B. amyloliquefaciens and B. subtilis, is a collection of closely related species that has been widely used as a probiotic due to its broad-spectrum antimicrobial activity and other benefits. However, how the probiotics-derived antibacterial phenotype contributes to infection control is still unclear. Methods: In this study, we used two different antibacterial phenotype strains, B. amyloliquefaciens and B. subtilis, to treat S. Pullorum infections. The spores of two strains (10⁷ CFUs) were supplemented daily for 21 days. Results: The reduction in body weight gains and the severity of S. Pullorum-induced symptoms were ameliorated. Compared to B. subtilis, B. amyloliquefaciens exhibited a stronger host protection effect, manifested in a greater reduction in the bacterial load of S. Pullorum in organs throughout the infection. Furthermore, both strains enhanced cecal microbiota diversity, suppressed infection-associated taxa, and promoted beneficial genera. Conclusions: Our findings demonstrate that probiotic Bacillus can alleviate S. Pullorum infection and improve growth performance in poultry, especially the antimicrobial phenotype contributing to pathogen clearance. This work provides crucial insights for developing effective, probiotic-based strategies against Pullorum disease. Full article

Nitrous oxide (N₂O) emissions from agricultural soils are an important source of greenhouse gases and are strongly influenced by fertilization practices. In this study, a field experiment was conducted from 24 June to 12 October 2024, at a saline-alkali farmland site in Binzhou, Shandong Province, China, to evaluate the effect of Bacillus subtilis biofertilizer on N₂O emissions and to explore the underlying mechanisms. Compared with conventional chemical fertilization, the Bacillus subtilis biofertilizer treatment reduced the cumulative N₂O emission flux by 39%. At the N₂O emission peak, the emission flux under the biofertilizer treatment was 40.7%, 18.2% lower than that under the CF and CBF treatments, respectively. Functional gene analysis further showed that at the N₂O emission peak, the biofertilizer treatment reduced the copy number of Bacterial-amoA by 94% and 83% relative to CF and CBF, respectively, while the hao gene abundance in the CF treatment was 7.67, 24 times higher than that in the BF and CBF treatments, indicating that the reduction in N₂O emissions was closely associated with suppression of the nitrification process. In addition, the biofertilizer treatment showed the highest plant nitrogen uptake. All fertilization treatments significantly increased crop yield compared with the control, whereas there was no significant difference in yield among BF, CF, and CBF treatments (p > 0.05). These findings indicate that B. subtilis biofertilizer can mitigate N₂O emissions from saline-alkali farmland without reducing crop yield and may represent a promising strategy for sustainable agricultural management. Full article

Excessive acidity restricts the utilization of citrus pulp, a major by-product of the dried tangerine peel industry. To overcome this bottleneck, a functional microbial consortium (BsHpMrF) comprising Bacillus subtilis L4, Hanseniaspora pseudoguilliermondii B4, and Monascus ruber CGMCC 10910 was constructed for efficient biological deacidification. The consortium exhibited a synergistic effect, achieving an 88.23% reduction in total acidity and converting the acidic pulp into a neutral, bio-stabilized substrate. Untargeted metabolomics analysis revealed that this efficiency was driven by the concurrent activation of the TCA cycle and glyoxylate shunt for organic acid mineralization, coupled with membrane lipid remodeling (increased unsaturation) to enhance acid tolerance. Notably, the fermentation process functioned as a “metabolic factory”, significantly enriching the matrix with bioactive lipids (e.g., 10-HDA, nervonic acid) and indole-3-acetic acid (IAA, 414.28 mg/L). Application assays demonstrated that the fermentation products acted as a potent biostimulant for soybean sprouts, significantly promoting lateral roots and eliciting the accumulation of antioxidant phenolics and flavonoids. This study provides a sustainable “waste-to-treasure” strategy, valorizing acidic citrus pulp into a functional biostimulant for high-quality edible sprout production, thereby achieving a sustainable “waste-to-food” circular loop. Full article

Isomaltulose is produced via sucrose isomerase catalysis by Serratia plymuthica A30. The enzyme was expressed in Bacillus subtilis using surface display, in combination with Bacillus subtilis spore coat CotC. The promoter was further selected and optimized to determine P_amyE as the most suitable promoter, while the spore coat protein assay reveals CotC as optimal. By scanning and analyzing the catalyst motifs with single-point mutation construction, a maximum isomaltulose yield of 27.21 mg/mL was recorded in the F181I-mutant enzyme. Another strain encoding the H363P-mutant reached a maximum yield of 20.84 mg/mL, while the k_cat value also increased from 17.64 to 24.80. Structural analysis showed that the F181I-mutant had higher thermostability, whereas the H363P-mutant had increased k_cat. Both mutants displayed a 5-fold increase in isomaltulose yield with relatively simple construction procedures, making them suitable for high-level isomaltulose production. Full article