Search Results (356)

Background: Inflammatory bowel disease (IBD) is a gut-based idiopathic disease characterized by chronic and relapsing inflammatory progression and intricate pathophysiology. It is now known that the key etiologies of IBD include immune dysregulation, imbalances in the gut microbiota, and metabolic disruptions. Probiotics are now the potential treatment for IBD, due to their ability to regulate the host immune system and microbiota of the gut. Methods: The current study analytically tested the preventive benefit of Bacillus licheniformis BL-01 on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) and also expounded on its molecular pathogenesis. Results: Our results demonstrate that supplementation with BL-01 effectively mitigates DSS-induced weight loss, an elevated disease activity index (DAI), and colonic tissue injury in mice. Concomitantly, BL-01 rectifies dysregulated inflammatory cytokine profiles, attenuates oxidative stress, and restores the expression of colonic tight junction proteins as well as the number of goblet cells. Furthermore, BL-01 modulates the gut microbiota diversity by increasing the abundance of beneficial bacterial genera such as Duncaniella and decreasing the abundance of pathogenic genera such as Helicobacter. Notably, BL-01 restores DSS-induced microbial metabolic dysregulation, modulates key metabolic pathways including arachidonic acid metabolism and steroid hormone biosynthesis, and regulates associated metabolites to ameliorate UC. Finally, Bacillus licheniformis BL-01 mitigates oxidative stress, reverses gut dysbiosis and metabolic disorders, and has a protective effect on UC. Conclusions: The findings give new information on the development of probiotic-based therapeutics in the prevention and treatment of IBD. 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

Bacteria adapted to elevated temperatures are commonly associated with geothermal environments and are recognized for their functional diversity. In this study, cultivable bacteria were isolated from a geothermal spring in northern Sinaloa, Mexico, and characterized through physicochemical analysis, molecular identification, growth kinetics, and functional screening. The isolates were identified as Bacillus licheniformis (strains J1, J3, and J8) and Brevibacillus borstelensis (strains J6 and J9). Growth analyses showed that, in nutrient broth at 45 °C, the evaluated strains exhibited specific growth rates ranging from 1.25 to 1.78 h⁻¹ and short doubling times between 23 and 33 min, with B. borstelensis J6 displaying the highest rate. At 50 °C, μmax values ranged from 0.77 to 1.08 h⁻¹, indicating sustained growth at elevated temperatures. Functional assays demonstrated extracellular proteolytic, amylolytic, and cellulolytic activities, mainly associated with B. licheniformis strains, in addition to tolerance to the pesticides fluazinam and benomyl. Antagonistic tests showed that B. licheniformis J8 inhibited the phytopathogenic fungi Sclerotinia sclerotiorum and Sclerotium rolfsii, while qualitative mineral solubilization assays indicated the ability of selected isolates to mobilize phosphate and potassium. These findings highlight geothermal ecosystems as valuable reservoirs of thermotolerant bacteria with enzymatic versatility and environmental relevance, supporting further molecular and process-optimization studies. Full article

Solid-state fermentation (SSF) is a long-established biotechnological approach gaining renewed interest for its ability to enhance nutrient availability and improve the functional properties of agro-industrial by-products. This strategy is particularly relevant for early post-weaning piglets, which are highly susceptible to weaning stress due to an immature digestive system and a gut microbiota not yet adapted to solid feed. In this study, the fermentation parameters of flaxseed cake were optimized using a Plackett–Burman experimental design. Protease activity was selected as the response variable due to its relevance for improving protein degradation and potential digestibility in fermented feed ingredients. Accordingly, based on the statistical analysis, the conditions selected for the in vivo trial were 1% molasses, 0.5% yeast extract, 0.05% CaCl₂, 0.5% NaCl, 7.5% inoculum (4.12 × 10⁹ CFU/mL), 60% moisture, and 72 h fermentation. Fermentation time was identified as the main factor positively influencing protease production, while higher CaCl₂ concentrations and inoculum levels negatively affected enzyme activity. Optimization increased protease activity, microbial viability and free amino acid content. In addition, SSF reorganizes the carbohydrate profile by reducing structural fiber fractions, with neutral detergent fiber and acid detergent fiber decreasing by 27% and 29%, respectively, while simultaneously increasing soluble carbohydrates by 14.67%. Phytic acid content being also reduced by 23.81%. A pilot nutritional trial on post-weaned piglets (35 days old) showed that including 8% fermented flaxseed cakes (FFSC group) improved body weight, average daily gain, feed conversion ratio, and diarrhea score, without affecting average daily feed intake, compared with 8% unfermented flaxseed cakes (FSC group). These performance improvements were accompanied by changes in fermentation metabolites and gut microbial composition. Lower isovalerate concentrations suggested reduced proteolysis, while higher propionate levels may contribute to increased blood glucose availability in the FFSC group. These changes coincided with a shift in microbial composition, characterized by a reduced abundance of methanogenic archaea and increased abundances of taxa such as Lactobacillus, Enterococcus, and members of the Lachnospiraceae and Eubacteriaceae families. Full article

Sporulation represents a complex metabolic reprogramming process in bacteria. In this study, we used CRISPR-Cpf1 to knock out spoIIE and rsfA in Bacillus licheniformis. The ΔspoIIE strain completely lost sporulataion capacity, while ΔrsfA showed a 25% reduction. Although viable cell counts decreased by 80.7% and 45.7%, respectively, glucose consumption and 2,3-butanediol synthesis remained unchanged, and acetoin synthesis increased by 19% in ΔspoIIE. Per-cell metabolic rates were significantly enhanced: glucose uptake increased 2.7–3.4-fold, acetoin synthesis 2.3–4.2-fold, 2,3-butanediol synthesis 1.7-fold, and heterologous protein expression 10–15-fold. These findings demonstrate that blocking sporulation liberates metabolic resources and enhances the specific productivity of vegetative cells, providing a strategy for engineering high-performance B. licheniformis cell factories. Full article

Probiotics have emerged as an important strategy to achieve improved feed efficiency and carcass quality. To evaluate the effects of a probiotic combination based on Weizmannia faecalis (formerly Bacillus coagulans) and Bacillus licheniformis on broiler performance, carcass, and intestinal health, a study was conducted. As-hatched ROSS 308 broilers were purchased from a local hatchery at day 0 and were randomly allocated to two treatments (160 birds per treatment; 8 replicates of 20 birds each): the control, which was fed a standard commercial diet throughout the experiment, and the probiotics group, where the standard diet was further supplemented with the probiotic combination. Feed and water were offered for ad libitum consumption while the feeding schedule was as follows: Starter, 1–10 days, mash; Grower, 11–24 days, mash; Finisher, 25–42, mash. The birds were challenged using re-used litter as bedding and the application of increased stocking density and mild heat stress. The final body weight of the probiotics’ supplemented group was higher than the control at 42 days of age (2822.7 g vs. 2575.4 g, respectively) (p < 0.05), and the overall feed conversion ratio was significantly reduced. The weight of all the commercial parts increased, along with the thigh and drumstick yield, thus indicating an improvement of carcass composition (p < 0.05). The European Poultry Efficiency Factor significantly improved following the probiotic dietary supplementation (409.7 vs. 344.9 of the control), while the probiotic fed birds had higher antibody titers for Bursal disease at 42 days and lower serum concentration of fatty acid binding protein 2 at 24 days (p < 0.05). Overall, the dietary supplementation of broilers with the probiotic mixture, under challenging rearing conditions, enhanced growth performance and improved carcass composition. Full article

Heat stress (HS) is one of the most challenging environmental conditions, responsible for impaired growth and reproduction in living systems. It also leads to altering the release of different biochemicals responsible for controlling the metabolic pathway. Five White Wistar rats were exposed at 42 ± 1 °C inside a closed chamber for the induction of hyperthermia. Their rectal temperature was recorded before and after heat exposure. The semi-digested food from the gut (colon) of sacrificed rats was collected under sterilized conditions for the isolation of gut bacteria on a nutrient agar plate at 50 °C, 60 °C, and 70 °C. The sample was incubated for 24 h and isolates were further purified. The proteolytic, amylolytic, cellulolytic, and xylanolytic activities were measured via plate assay and the enzymatic index was calculated. Total protein and estimation of heat shock protein 70 (HSP70) were also quantified. Initially, the rectal temperature of the animal was 37.1 ± 0.2 °C, but after exposure to heat, the temperature was 40.8 ± 0.2 °C. The number of purified isolates was recorded, i.e., at 50 °C (04), at 60 °C (01), and at 70 °C (03). Among eight isolates, Bacillus licheniformis (50 °C) showed all four enzymatic activities with a higher enzymatic index. Further, this novel isolate also exhibited a maximum concentration of HSP70. This preliminary study reveals the survival of a bacterium (B. licheniformis) capable of producing key metabolites, highlighting its significance in supporting host physiology and other pathophysiological conditions. As a probiotic, it may serve as a potential therapeutic bridge connecting HSP70, host physiological function, and gut health. Full article

This study investigated the physiological benefits of probiotic supplementation during refeeding after short-term fasting in Nile tilapia (Oreochromis niloticus). A total of 180 fish were assigned to three groups: continuously fed control or subjected to 5 days of fasting followed by 15 days of refeeding with either a basal or probiotic-enriched diet containing Bacillus subtilis, B. licheniformis, and B. pumilus. Growth performance indices (body weight, length, weight gain, specific growth rate, condition factor, relative feed intake, and feed conversion ratio) were measured. Muscle samples were collected for histomorphological evaluation and quantitative real-time PCR analysis of antioxidant genes catalase (cat) and superoxide dismutase 2 (sod-2), growth-related genes insulin-like growth factor 1 (igf-1) and suppressor of cytokine signaling 2 (soc-2), anti-inflammatory gene transforming growth factor beta (tgf-β), and myostatin genes. Fasting significantly reduced (p < 0.05) body weight compared to control, confirming the impact of nutrient deprivation. Upon refeeding, fish on the basal diet showed partial growth recovery but remained below control levels, whereas probiotic-fed fish exhibited superior recovery, surpassing both control and basal groups in body weight, length and weight gain. Condition factor exhibited insignificant changes among all groups after fasting and upon refeeding. Specific growth rate of the entire experiment was highest in the probiotic group, while insignificant. Relative feed intake decreased in both refed groups, yet feed conversion ratio improved, particularly with probiotics. Gene expression analysis revealed fasting-induced upregulation of antioxidant (cat and sod-2) and myostatin (p < 0.05), alongside downregulation of growth-related (igf-1 and soc-2) and anti-inflammatory (tgf-β) genes (p < 0.05). Basal refeeding restored most expressions, whereas probiotics enhanced antioxidant, growth, and anti-inflammatory genes while normalizing myostatin (p > 0.05 vs. control). Histological evaluation showed fasting-induced muscle atrophy, which was most effectively reversed by probiotics. Overall, probiotics accelerated recovery, highlighting their potential to optimize post-fasting growth in aquaculture. Full article

Bacteria represent promising tools for reducing the use of synthetic inputs in crop production. In this study, we evaluated the effects of two bacterial strains isolated from chicken compost tea—Bacillus licheniformis and Pseudomonas mendocina—on the yield and quality of strawberry. Experimental assays were conducted in two seasons (2023 and 2024) under macro-tunnel conditions, with the following treatments: control without applications (Con); commercial NPK fertilizer (FerC); application of B. licheniformis (BL) and P. mendocina (PM) solution in soil once a month. Both bacterial treatments enhanced soil properties. Fruit individual weight significantly increased in BL treatment compared to the control. Similar trends were observed for anthocyanin and ascorbic acid content (increases > 25%), as well as for antioxidant activity (increases of more than 20% and 13% for BL and PM, respectively). The differences were more significant in 2023. In addition, both strains showed positive in vitro results for phytase, siderophore, and IAA production (5.8–8.8 and 9.3–13 µg IAA/mL for BL and PM after 15 days). Although further field validation is required, these results indicate that bacteria (particularly B. licheniformis) show strong potential as bioinoculants to enhance the productivity and quality of strawberry. Full article

Quinoa (Chenopodium quinoa) is a promising source of plant proteins with the potential to produce bioactive peptides through enzymatic hydrolysis. This study aimed to extract quinoa protein and produce bioactive peptides using two microbial proteases: Alcalase (from Bacillus licheniformis) and Flavourzyme (from Aspergillus oryzae). The protein was extracted through alkaline solubilization and isoelectric precipitation, achieving a 72% yield. Hydrolysis was conducted for 4 h, and enzymatic activity was measured using the TNBS method to determine the degree of hydrolysis, while SDS-PAGE was used to analyze protein breakdown. The reaction was performed at controlled pH and temperature (Alcalase: 9.5 and 55 °C; Flavourzyme: 7 and 37 °C). Both enzymes achieved maximum hydrolysis at 60 min. Consequently, the separation and inhibitory capacity of angiotensin-converting enzyme (ACE-I) were tested at the first four time points (0, 20, 40, and 60 min). A wider variety and higher concentration of peptides smaller than 2 kDa were found in hydrolysates treated with Flavourzyme, which is associated with antihypertensive activity. The ACE-I assay showed greater activity at the end of hydrolysis. Inhibition percentages of 87.5 ± 2.11 were observed in hydrolysates with Flavourzyme, and 94.1 ± 1.11 in those with Alcalase. These findings indicate that quinoa protein, hydrolyzed with microbial proteases, is a feasible source of peptides with potential antihypertensive effects for use in functional foods and nutraceuticals. Full article

Bacillus species are among the most widely used microbial agents in agricultural biocontrol, reflecting their ecological resilience, functional diversity, and long history of practical application. The antagonistic activity of Bacillus spp. against plant pathogens and their plant growth–promoting effects are well established. However, these biological functions are frequently considered in isolation from safety evaluations and regulatory decision-making, resulting in a fragmented evidence base. This review addresses this gap by providing an integrated synthesis of agriculturally relevant Bacillus taxa, explicitly linking biocontrol performance with strain-level safety considerations and regulatory assessment. This review focuses on the principal groups currently applied in agriculture, including the Bacillus subtilis lineage, notably B. amyloliquefaciens, B. velezensis, B. pumilus, and B. licheniformis, as well as B. thuringiensis and Cytobacillus firmus. Key mechanisms underlying biocontrol efficacy are examined alongside evidence from greenhouse and field applications. These mechanisms include the production of secondary metabolites and volatile compounds, biofilm formation, rhizosphere colonisation, and the induction of plant defence responses. Attention is given to environmental and operational factors that influence the consistency of performance. A central contribution of this review is the integration of functional evidence with safety-relevant considerations, such as realistic metabolite exposure, antimicrobial resistance potential, and ecological effects. Regulatory approaches in the European Union, the United States, and selected Organisation for Economic Co-operation and Development countries are compared to illustrate how such evidence informs risk assessment and supports the sustainable use of Bacillus-based biocontrol agents in modern agriculture. Full article

In Brazil, the olive tree (Olea europaea) is propagated by cuttings using indole-3-butyric acid (IBA) for rooting and sand as the substrate. Auxin-producing microorganisms may enhance this process when applied together with IBA. This study evaluated the rooting capacity of cuttings from four olive cultivars—Arbequina, Maria da Fé, Ascolano 315, and Koroneiki—treated with commercial products based on microorganisms, plus IBA. The biostimulants used were Bacillus amyloliquefaciens, Bacillus licheniformis, Bacillus subtilis, Trichoderma harzianum, and the commercial product Bioraiz^® (a mixed mineral fertilizer) in liquid formulation. Trichoderma harzianum and Bacillus spp. improved the quality of rooted cuttings, promoting the formation of more roots per cutting (about 10) and longer roots, on average of 8.1 cm in the cultivars Maria da Fé, Ascolano 315, and Arbequina. Cuttings treated with Trichoderma harzianum, Bacillus subtilis, and Bacillus licheniformis produced higher percentages of rooted cuttings, over 50%, and more developed root systems. Conversely, the control and Bioraiz^® showed weaker rooting performance, producing fewer than seven roots per cutting. Overall, the results highlight the potential of biostimulant applications, such as Trichoderma and Bacillus subtilis, as promising tools to optimize the rooting of olive tree cuttings, whereas the fertilizer showed limited effectiveness in promoting rooting. Full article

As synthetic biology advances, prokaryotic microorganisms have become critical platforms for heterologous biosynthesis in cell factory applications. However, conventional free enzyme systems encounter substantial challenges, including inefficient intermediate transfer, toxic intermediate accumulation, and vulnerability to temperature and pH fluctuations. Enzyme complex catalytic systems offer promising solutions to these limitations. Bacillus licheniformis, a Generally Recognized as Safe (GRAS) host with exceptional protein secretion capacity, represents an ideal chassis for enzyme complex construction. This study developed a peptide-mediated platform in B. licheniformis to enable enzyme complex self-assembly and evaluated its effects on metabolic pathway performance. Five peptide elements were screened through fusion with enhanced orange/green fluorescent proteins (eOFP/eGFP) and transglutaminase (TGase). Effective peptide pairs were identified by measuring fluorescence intensity, visualizing complex formation via laser confocal microscopy, and assessing TGase activity. Subsequently, recombinant strains expressing peptide-fused key metabolic enzymes (gadTt and KdgA) were constructed for whole-cell biotransformation using gluconate as substrate to investigate the impact of peptide-mediated enzyme complexes on pyruvate synthesis. In the fluorescent protein system, P18/D18—amphipathic peptides that drive enzyme self-assembly via intermolecular hydrophobic interactions—increased extracellular fluorescence intensity of eOFP and eGFP by 31.11% and 25.21%, respectively. The D18 peptide significantly elevated TGase activity by enhancing structural stability to over 1.3-fold that of the control. For pyruvate synthesis, the peptide-mediated enzyme complex exhibited remarkable advantages in substrate conversion rate (up to 53.08%) and thermostability, confirming the platform’s ability to enhance substrate channeling despite no optimization for absolute yield. This study established a novel peptide-mediated multienzyme self-assembly platform in B. licheniformis, providing a valuable strategy for artificial metabolic channel design in synthetic biology. Full article

Calcareous soils are typically deficient in essential nutrients such as iron, phosphorus, and potassium, which frequently results in nutrient deficiency in fruit trees. Bacillus licheniformis LCDD6 markedly enhanced Malus hupehensis seedling growth and plant iron nutrition in calcareous soil. This study aimed to elucidate the mechanism underlying these beneficial effects of strain LCDD6 under iron deficiency. Transcriptomic analysis revealed that iron deficiency induced metabolic reprogramming in strain LCDD6, characterized by a significant upregulation of genes involved in the biosynthesis of the siderophore bacillibactin and plant growth hormone indoleacetic acid (IAA). Consistently, metabolomic profiling identified bacillibactin and IAA as the dominant metabolites produced under iron-deficient conditions. A 60-day pot experiment further demonstrated that the cell-free fermentation broth of strain LCDD6 significantly enhanced plant growth and rhizosphere soil enzyme activities. The crude bacillibactin extract derived from the fermentation exerted the strongest effects on plant growth and iron accumulation, whereas IAA preferentially stimulated root development and promoted plant phosphorus accumulation. Additionally, different metabolites exerted distinct and selective effects on the rhizosphere microbial community, with fungi showing stronger and more metabolite-specific responses than bacteria. The crude bacillibactin extract enriched fungal taxa, particularly Coprinellus, which showed strong positive correlations with plant growth traits and iron accumulation, while Stachybotrys, enriched under IAA treatment, was positively correlated with plant phosphorus content. Overall, strain LCDD6 promotes plant growth under iron-deficient conditions through the coordinated action of multiple metabolites, with bacillibactin as the primary contributor and IAA providing complementary effects. These findings offer mechanistic insight and a scientific basis for developing Bacillus-based biofertilizers to improve nutrient acquisition in calcareous soils. Full article

Rice bran, a nutrient-rich by-product of rice milling, is an underutilized resource in sustainable crop utilization. This study aimed to investigate the characteristics, total phenolic content, and antioxidant activities of rice bran protein hydrolysates (RBPHs) produced using proteases from Bacillus licheniformis (RBPH-B) and α-chymotrypsin (RBPH-C), along with their protein fractions (F1; >100 kDa, F2; 10–100 kDa, F3; 1–10 kDa, F4; <1 kDa). Molecular weight, color, surface hydrophobicity, secondary structure, total phenolic content, and antioxidant activities of the hydrolysates were assessed. Both enzymatic hydrolysis and ultrafiltration reduced molecular weight and surface hydrophobicity, enhanced lightness, and increased α-helix content. Among all samples, the <1 kDa peptide fraction derived from α-chymotrypsin hydrolysis (RBPH-C-F4) exhibited the strongest antioxidant activity, with the lowest EC₅₀ values for ABTS (0.94 mg/mL) and DPPH (210 µg/mL), as well as the highest inhibition of metal chelating activity (1.35 mmol EDTA/g sample) and linoleic peroxidation (90.62%). Enzymatic hydrolysis enhanced total phenolic content compared with native rice bran protein. These findings highlight the potential of rice bran-derived peptides as antioxidant candidates and indicate that further validation in food systems is required. Full article