Search Results (165)

The fall armyworm (FAW), Spodoptera frugiperda, poses a major threat to global maize production. Reliance on synthetic pesticides has contributed to pest resistance and environmental degradation, underscoring the need for sustainable alternatives. In this study, ethanolic extracts of neem (Azadirachta indica) and moringa (Moringa oleifera), together with maize-associated bacterial isolates, were evaluated for their biocontrol potential against fall armyworm. Gas chromatography-mass spectrometry (GC-MS) analysis for bioextract identification revealed tissue-specific chemical diversity, identifying eight key phytochemicals, including octadecanoic acid, trimethyl fluorosilane, and hexadecanoic acid in neem, and trimethyl fluorosilane, ethyl oleate, ethyl (9Z,12Z), octadecanoic acid, and benzenedicarboxylic acid in moringa extracts. Eighty-nine bacterial isolates were screened for extracellular enzyme activities (cellulase, chitinase, glucanase, and protease) and siderophore production, among which four strains, DR-55 (Bacillus subtilis), HL-7 (Bacillus cereus), HL-37 (Bacillus cereus), and DR-63 (Enterobacter sp.), exhibited >50% biocontrol efficacy under greenhouse conditions. A strong correlation (r = 0.88) was observed between in vitro antagonistic activity and greenhouse performance, validating the screening approach. Fall armyworm mortality was the highest in larvae (up to 80%), moderate in pupae (15–17%), and the lowest in adults (6–7%), respectively. Overall, plant bio-extracts and maize-associated microbial isolates represent a promising, non-hazardous strategy for sustainable fall armyworm management while preserving maize plant health. Full article

Latex-producing plants harbor unique microbial communities that may play important roles in host defense; however, their diversity and biocontrol potential remain largely unexplored. Characterizing these communities provides opportunities to identify novel microbial-derived antifungal agents for sustainable crop protection. Bacterial strains were isolated from the latex of Alstonia scholaris (L.) R. Br. and identified using 16S rRNA gene sequencing. Antifungal activity was evaluated against four phytopathogens: Fusarium graminearum, Colletotrichum musae, Colletotrichum gloeosporioides, and Glomerella cingulata. Bioassay-guided fractionation, size-exclusion chromatography, SDS-PAGE, and LC-MS/MS were used to characterize antifungal proteins. Nine bacterial strains were isolated, including eight Bacillus spp. and one Enterococcus faecalis. Among them, Bacillus sp. AsL-2 exhibited the strongest broad-spectrum antifungal activity, inhibiting fungal growth by up to 80%. The antifungal activity of its crude extract remained stable over a wide temperature range. Further characterization identified a novel endo-β-1,3-1,4-glucanase enzyme (~23 kDa) as the major antifungal protein. This study reveals A. scholaris latex as an underexplored microbial niche and identifies Bacillus sp. AsL-2, affiliated with the B. velezensis–B. amyloliquefaciens species complex, as a promising biocontrol candidate. The identified antifungal enzyme represents a potential natural alternative to synthetic fungicides for sustainable agricultural disease management. Full article

In this study, we used a culture-dependent approach to explore the biochemical potential of bacteria associated with two genera of soft corals collected from the Red Sea (phylum Cnidaria, class Anthozoa, subclass Octocorallia, order Alcyonaceae, and family Alcyoniidae). The soft corals were identified as Cladiella sp. and Paralemnalia sp. The associated bacteria were isolated on marine agar, nutrient agar, starch casein agar, ISP2 Agar, and M1 agar. The highest proportion of strains was recovered using marine agar, followed by nutrient agar and M1. We focused on Gram-positive bacteria and evaluated their cytotoxicity and antimicrobial activity. About 24% of the bacterial samples demonstrated promising cytotoxicity against Ehrlich ascites carcinoma (EAC). Out of 12 bioactive isolated strains, two bacterial isolates showed strong cytotoxicity, with IC₅₀ values of 134.47 and 148.5 µg/mL, respectively. Nine isolates displayed significant antimicrobial activity against two tested pathogens. Based on the 16S rRNA gene sequence, two bioactive bacterial isolates were identified as Bacillus subtilis and Microbacterium sp. These findings indicate that bacteria associated with soft corals could be a valuable source of new bioactive compounds with potential uses in drug development. Furthermore, our data add important insights to the understudied field of host-microbiome relationships in soft corals. Full article

This study investigated the effects of Bacillus subtilis (B. subtilis) supplementation on microbiota and metabolites in the feces of Leizhou goats. Eight Leizhou goats were used in a replicated 4 × 4 Latin square design according to their gender (nanny goats and billy goats) with a 4 × 2 factorial arrangement of treatments that included four B. subtilis additive doses (control [0 g/d; NC, BC], low [2.5 g/d, NL, BL], medium [5 g/d, NM, BM], and high [7.5 g/d, NH, BH]) and 28 d periods (n = 4 per group), each consisting of 27 d adaption and 1 d sample collection. After collecting 32 fecal samples, 16S rRNA gene sequencing and LC-MS were performed to analyze microbial composition and metabolites, respectively. At the genus level, the relative abundance of Rikenellaceae_RC9_gut_group was significantly higher (p < 0.05) in the NM group than in the NC group. The relative abundance of Treponema sp. was significantly lower (p < 0.05) in the NM group than in the NC group. In billy goats, the relative abundances of UCG-005 and Rikenellaceae_RC9_gut_group were significantly higher (p < 0.05) in the BH group than in the BC group. The relative abundance of Treponema sp. was significantly lower (p < 0.05) in the BL, BM, and BH groups than in the BC group. Furthermore, metabolomic analysis revealed that B. subtilis significantly altered the concentrations of glucose metabolism modulators (1-deoxynojirimycin, 1-DNJ) and certain bioactive peptides. Many amino acid metabolic pathways were also enriched. Correlation analysis demonstrated close connections between differential metabolites and the top 10 bacterial genera in fecal samples. These results provide new insights into the impact of B. subtilis on the microbial community and metabolic profile of the feces of Leizhou goats. In this experiment, the appropriate doses of B. subtilis for nanny goats and billy goats were 5 g/d and 7.5 g/d, respectively, but the optimal doses still need to be verified based on performance-based feeding tests in the next study. Full article

Whether consecutive annual incorporation of rice straw can enrich straw-decomposing microorganisms, and what common and distinct dominant straw-degrading microbial populations exist in soils under long-term rice straw incorporation across different regions of Fujian Province, remain relatively unexplored. To address this, soil samples were collected from rice cultivation areas with consecutive straw incorporation located in different geographical directions within Fujian Province. A straw burial pot experiment was conducted, and high-throughput sequencing was employed to analyze the bacterial and fungal community compositions in these soils. Furthermore, the degradation potential of the soil microbial communities towards rice straw was determined. The results revealed that the dominant bacterial phyla associated with straw degradation across the four treatments were Proteobacteria, Actinobacteriota, Firmicutes, and Chloroflexi, while the dominant fungal phyla were Ascomycota and Basidiomycota. At the genus level, the relative abundance of the dominant bacterial genus, Bacillus, showed a positive correlation with the straw degradation rate but a negative correlation with soil pH. In contrast, the dominant fungal genera, Zopfiella and Chaetomium, were positively correlated with both the straw degradation rate and soil pH. Furthermore, a strain designated PC1 was isolated and screened from the PC treatment samples. Sequencing of the rDNA-ITS region identified PC1 as Chaetomium sp. The degradation rate of rice straw by strain PC1 reached 49.13%, which was higher than the degradation rate observed in the PC treatment in the pot burial experiment. This finding provides a theoretical foundation for the potential application of efficient lignin-degrading fungi in field-scale straw degradation. Full article

Longya Lily (Lilium brownii var. viridulum) bulb rot, a devastating soil-borne disease caused by Fusarium oxysporum f. sp. lilii (Fol L1-1), severely compromises yield and quality of this economically significant crop. In this study, strain R12 was isolated from the rhizosphere soil of asymptomatic Longya lily plants and identified as Bacillus velezensis. The strain significantly disrupted the spore germination and hyphal morphology of Fol L1-1. In pot experiments, R12 not only effectively suppressed disease development but also promoted plant growth, a trait potentially linked to its indole-3-acetic acid (IAA) production capacity. Genomic analysis revealed a 4,015,523 bp circular chromosome (46.42% GC content) harboring gene clusters for the synthesis of diverse secondary metabolites, including surfactin, fengycin, difficidin, and bacillibactin. These findings highlight the potential of B. velezensis R12 as a biocontrol agent and provide insights into its mechanisms for suppressing phytopathogens and promoting plant growth. Full article

Background/Objectives: The growing threat of antimicrobial resistance has intensified the search for alternative therapeutic approaches. Quorum sensing (QS) inhibition, which disrupts bacterial communication and virulence, represents a promising approach to mitigating infection. Given the complexity of the sponge holobiont, sponge-associated microorganisms may demonstrate QS inhibitory properties and serve as potential sources of novel anti-virulence agents. This study aimed to investigate the QS inhibitory potential of sponge-associated Bacillus species against Pseudomonas aeruginosa, a multidrug-resistant pathogen that relies on QS for virulence regulation. Methods: Ninety-eight bacterial isolates were obtained from seven intertidal South African sponges. Biosensor-based sandwich assays using Chromobacterium violaceum identified 15 isolates with putative QS inhibition (QSI) activity, including five classified as Bacillus species via 16S rRNA gene sequencing. Crude extracts from these isolates, cultivated in medium Mannitol (Mann) and medium 5294, were screened for their ability to inhibit QS-regulated virulence factors in P. aeruginosa. Results: Extracts, particularly from medium 5294, exhibited significant QSI activity without cytotoxic effects. The five most potent extracts, i.e., Bacillus mobilis SP2-AB7 (5294), Bacillus wiedmannii SP5-AB7 (Mann), B. mobilis SP2-AB7 (Mann), and Bacillus cereus SP1-AB4 (Mann and 5294), inhibited both Las- and Rhl-regulated virulence factors, including pyocyanin, pyoverdine, elastase, protease, rhamnolipid production, motility, and initial adhesion, achieving inhibition rates of up to 93% (p < 0.05). Molecular analysis confirmed the presence of the aiiA lactonase gene in key isolates, while GC-MS and FTIR profiling revealed medium-specific differences in metabolite production. Conclusions: Sponge-associated Bacillus species from KwaZulu-Natal exhibit robust QSI activity against P. aeruginosa, highlighting their potential as sources of alternative anti-virulence agents. Further characterization and in vivo validation are needed to assess their therapeutic application in combatting resistant infections. Full article

Chili (Capsicum annuum L.) is a herbaceous vegetable grown and consumed worldwide. In Thailand, chili plants are severely hampered by anthracnose disease, leading to severe yield losses. This study aimed to investigate endophytic bacteria (EPB) for their potential as a biocontrol agent and plant growth promoter (PGP). Among a total of 108 isolates, strain KKU-RE-018 was identified by partial 16S rRNA gene sequencing as belonging to the genus Bacillus. This isolate exhibited strong antifungal activity against Colletotrichum capsici; its activity occurred through the production of hydrolytic enzymes, including chitinase and β-1,3-glucanase, and exhibited PGP properties. This endophytic bacterium significantly reduced anthracnose severity compared with the control, achieving a disease reduction index (DRI) of over 60%. Moreover, chili plants treated with the bacterium showed higher plant growth parameters under greenhouse conditions. The levels of phenolic compounds and salicylic acid in plants treated with Bacillus sp. KKU-RE-018 could activate systemic acquired resistance (SAR). Taken together, these findings demonstrate that Bacillus sp. KKU-RE-018 plays a multifaceted role, capable of suppressing anthracnose and simultaneously promoting chili growth. Full article

Continuous cropping obstacles (CCOs) lead to a decline in yield and quality under repeated cultivation in the same farmland. Notably, CCOs caused by fusarium wilt, autotoxicity, or imbalance in rhizosphere microbial communities reduce the productivity of watermelons (Citrullus lanatus). Considering the negative environmental impacts of conventional agrochemicals, it is necessary to evaluate the biocontrol efficiency of microorganisms. Therefore, this study aimed to investigate the biocontrol efficiency of Bacillus amyloliquefaciens strain PP19 against CCOs of watermelon so as to develop alternatives to agrochemicals. The inhibitory effect of PP19 on watermelon fusarium wilt was assessed through plate confrontation assays and field trials. The degradation and utilization of autotoxins by PP19 were examined via co-culture experiments. Additionally, 16S rRNA sequencing was employed to analyze the impact of PP19 on the rhizosphere soil microbial community of watermelon. Specifically, we analyzed the PP19 utilization of four phenolic autotoxins secreted by watermelon roots and assessed their effects on microbial diversity in the watermelon rhizosphere. Plant growth assays showed that PP19 improved the weight and quality of watermelon fruit. Although PP19 inhibited the growth of Fusarium oxysporum f. sp. niveum (Fon), the growth inhibitory effect was significantly enhanced by autotoxins produced by watermelon, including mixed phenolic, cinnamic, ferulic, and p-coumaric acids. Additionally, PP19 effectively degraded and utilized the autotoxins, and the autotoxins enhanced PP19’s swimming ability and biofilm formation. Moreover, PP19 treatment significantly enhanced the microbial diversity in watermelon rhizosphere, increased the number of beneficial bacterial genera, and decreased the number of pathogenic genera. Conclusively, these results suggest that B. amyloliquefaciens strain PP19 improves the resistance of watermelon to CCOs by effectively utilizing and degrading autotoxin, altering soil microbial community structure, and inhibiting Fon17 growth, resulting in improved fruit quality. Overall, PP19 possesses potential application as a biological control agent against CCOs in commercial watermelon cultivation. Full article

Sustainable development requires implementation of eco-friendly practices and a circular approach in both agricultural and industrial systems. This study evaluated winery flotation wastewater (WFW) as a cultivation substrate for Bacillus sp. 10/R isolated from grapevine rhizosphere for sustainable biostimulant production. The bacterial isolate was characterized by 16S rRNA sequencing and biochemical tests, showing the highest similarity with Bacillus mojavensis and Bacillus halotolerans. Plant growth-promoting traits were assessed via assays for hydrolytic enzymes, ACC (1-aminocyclopropane-1-carboxylate) deaminase, and IAA (indole acetic acid) production, as well as for phosphate solubilization. The isolate was cultivated in WFW, including monitoring of biomass growth, enzymatic activity, and substrate composition changes. The resulting cultivation broths based on WFW (WFW-CB) and nutrient broth (NB-CB) were tested as barley seed treatment at five dosages, using sterile media and water as controls. The results have displayed strong pectinase (EAI–enzyme activity index 2.79) and cellulase activity (2.33), moderate xylanase (1.75) and ACC deaminase activity (growth zone 54.67 ± 0.58 mm), and moderate IAA production (9.66 µg/mL). Biomass content has increased by two log units within 48 h (up to 9.06 log CFU/mL), with stable pectinase activity (~2.2 U/mL). Germination assays revealed that 10% WFW-CB and 50% WFW enhanced germination indices and biomass, whereas undiluted WFW and WFW-CB inhibited germination. These results indicate that WFW is a suitable substrate for Bacillus sp. 10/R cultivation, linking industrial wastewater valorization with plant biostimulant production in a circular economy framework. Full article

Polyurethane (PU) is a widely used plastic material whose persistence in the environment entails a serious ecological challenge. This study aimed to isolate and characterize environmental bacteria capable of degrading PU, using Impranil DLN as a model substrate, and to investigate their enzymatic mechanisms and phylogenetic relationships. A total of 31 bacterial isolates were obtained from four waste accumulation sites and taxonomically identified across 12 different genera using MALDI-TOF MS and 16S rRNA gene sequencing. This analysis revealed genera not previously reported as PU biodegraders, including Priesta, Dermacoccus, Gordonia, Micrococcus, Pseudarthrobacter, and Agromyces. The Bacillus cereus clade was the most prevalent group, followed by the Priestia megaterium clade and Achromobacter sp. Biodegradation assays revealed high variability among strains, with the most efficient degrading over 90% of Impranil DLN. Protease activity was the most frequently detected enzymatic function, followed by urease and esterase activities. However, no clear correlation was observed between enzymatic profiles and degradation efficiency. Selected strains were tested on polyether PU foam, revealing biodegradative activity, an uncommon observation for bacteria on such recalcitrant material. These findings contribute to our understanding of bacterial diversity and enzymatic mechanisms involved in PU biodegradation, as well as their potential applications in plastic waste bioremediation. Full article

Microorganisms are crucial for the liquor brewing process and substantially impact liquor flavour and quality; therefore, understanding microbial succession is necessary. Most studies use a single-method approach and fail to provide an in-depth analysis. We aimed to combine traditional culture method with high-throughput sequencing (HTS) to identify the microbial diversity and succession in Luzhou-flavour fermentation. HTS revealed 932 bacterial and 980 fungal operational taxonomic units. 16S rDNA, 26S D1/D2 rDNA, and ITS v4/v5 isolated and identified 256 bacterial and 130 yeast strains. Population succession analysis showed that the dominant populations were yeasts, Lactobacillus, and Bacillus (early stage), and yeasts and Lactobacillus (late stage). Lactobacillus, Pichia, Bacillus, and Candida were abundant among all three layers of fermented grains. However, C. ethanolica, Saccharomycetes sp., and an unidentified Saccharomyces cerevisiae were more abundant in the lower layer than in the middle and upper layers, while L. parabuchneri, Oceanobacillus oncorhynchi, and Thermoactinomyces sp. were present only in the lower layer. Correlations among enzyme activity, volatile production, and dominant microbes during fermentation indicated that P. fermentans, L. suebicus, L. acetotolerans, P. kudriavzevii, P. exigua, and B. tequilensis were significantly affected during brewing. Our results lay a foundation for elucidating the microbial fermentation mechanism of Luzhou-flavour liquor and will assist in improving traditional liquor brewing quality and efficiency. Full article

Phytate, an antinutritional molecule in poultry feed, can be degraded by applying phytase, but its use in low- and middle-income countries is often limited due to importation instead of local production. Here, inexpensive raw materials were used to optimize the production of a thermostable phytase from an indigenous strain of Bacillus subtilis SP11 that was isolated from a broiler farm in Dhaka. SP11 was identified using 16s rDNA and the fermentation of phytase was optimized using a Plackett–Burman design and response surface methodology, revealing that three substrates, including the raw material mustard meal (2.21% w/v), caused a maximum phytase production of 436 U/L at 37 °C and 120 rpm for 72 h, resulting in a 3.7-fold increase compared to unoptimized media. The crude enzyme showed thermostability up to 80 °C (may withstand the feed pelleting process) with an optimum pH of 6 (near pH of poultry small-intestine), while retaining 96% activity at 41 °C (the body temperature of the chicken). In vitro dephytinization demonstrated its applicability, releasing 978 µg of inorganic phosphate per g of wheat bran per hour. This phytase has the potential to reduce the burden of phytase importation in Bangladesh by making local production and application possible, contributing to sustainable poultry nutrition. Full article

This study demonstrated that application of the particular plant growth-promoting rhizobacteria (PGPR) strains Erwinia sp. and Serratia sp. (named C15 and C20, respectively) significantly enhanced tea plant resilience in Zn (zinc)-, Pb (lead)-, and Zn + Pb-contaminated soils by the improving survival rates (over 60%) and chlorophyll content of tea plants, and by reducing the accumulation of these metals in tea plants’ tissues (by 19–37%). The PGPRs elevated key soil nutrients organic carbon (OC), total nitrogen (TH), hydrolysable nitrogen (HN), and available potassium (APO) and phosphorus (APH) contents. Compared to non-PGPR controls, both strains consistently increased microbial α-diversity (Chao1 index: +28–42% in Zn/Pb soils; Shannon index: +19–33%) across all contamination regimes. PCoA/UniFrac analyses confirmed distinct clustering of PGPR-treated communities, with strain-specific enrichment of metal-adapted taxa, including Pseudomonas (LDA = 6) and Bacillus (LDA = 4) under Zn stress; Rhodanobacter (LDA = 4) under Pb stress; and Lysobacter (LDA = 5) in Zn + Pb co-contamination. Fungal restructuring featured elevated Mortierella (LDA = 6) in Zn soils and stress-tolerant Ascomycota dominance in co-contaminated soils. Multivariate correlations revealed that the PGPR-produced auxin was positively correlated with soil carbon dynamics and Mortierellomycota abundance (r = 0.729), while the chlorophyll content in leaves was closely associated with Cyanobacteria and reduced by Pb accumulation. These findings highlighted that PGPR could mediate and improve in tea plant physiology, soil fertility, and stress-adapted microbiome recruitment under heavy metal contaminated soil and stress. Full article

Bacillus species have shown the potential to recover rare earth elements (REEs), but strains with adsorption selectivity for terbium(III) remain understudied. In this study, six Bacillus strains with the capability for efficient adsorption of Tb(III) were screened from an ionic rare earth mine and were identified based on 16S rRNA gene sequencing. Adsorption experiments showed that Bacillus sp. DW011 exhibited exceptional Tb(III) adsorption efficiency, with an adsorption rate of 90.45% and adsorption selectivity for heavy rare earth elements. Notably, strain DW011 was also found to be tolerant against Tb(III) with the 24 h 50% lethal concentration (LC₅₀) of 2.62 mM. The biosorption mechanisms of DW011 were investigated using adsorption kinetics, SEM-EDS, and FTIR. The results indicated that the adsorption of strain DW011 conforms to the second-order kinetic model, and the teichoic acid–peptidoglycan network (phosphate-dominated) serves as the primary site for heavy REE adsorption, while carboxyl/amino groups in the biomembrane matrix provide secondary sites for LREEs. This study provides new information that Bacillus strains isolated from ionic rare earth mine deposits have potential as green adsorbents and have high selectivity for the adsorption of heavy REEs, providing a sustainable strategy for REE recovery from wastewaters. Full article