Search Results (82)

The usability of flavonoids, which have numerous functional benefits, is limited by their low solubility. In this study, microorganisms were isolated from the soil of a buckwheat farmland located in Pyeongchang, Republic of Korea, to identify potential agents for flavonoid bioconversion. Strain 3P-1, which exhibited 98.9% 16S rRNA gene sequence similarity to Bacillus licheniformis strain IND706, demonstrated the ability to utilize flavonoids during fermentation. During the 7-day fermentation process with strain 3P-1, a significant decrease in quercetin content was observed, accompanied by the generation of an unknown compound. High-performance liquid chromatography coupled with mass spectrometry analysis of the unknown compound revealed its molecular weight. Among the four potential candidates identified, isoquercetin was determined to be the most likely agent for flavonoid bioconversion based on its biosynthetic pathway and substrate specificity, as well as known characteristics of strain 3P-1. These findings suggest that the isolated strain 3P-1 has substantial potential as a bioconversion agent for transforming quercetin to isoquercetin, which enhances its bioavailability. Full article

Zearalenone (ZEN), a non-steroidal estrogenic mycotoxin produced by Fusarium graminearum species, poses a significant threat to both human food safety and animal feed quality. In this study, we isolated a strain, designated as Bacillus licheniformis YJ25, from a contaminated moldy corn sample, demonstrating substantial effectiveness in removing ZEN. Our findings revealed that YJ25’s ZEN removal occurs primarily through cell wall adsorption, with enzymatic degradation representing a potential mechanism. In practical applications, enzymatic degradation may yield metabolites with heightened toxicity. However, liquid chromatography–mass spectrometry (LC–MS) analysis revealed that ZEN was not converted into α-/β-zearalenol (α-/β-ZEL) or α-/β-zearalanol (α-/β-ZAL) by YJ25, substantiating the safety profile of YJ25 in the removal of ZEN. Our mechanistic investigations revealed that the cell wall components peptidoglycan and teichoic acid serve as the primary binding sites for ZEN adsorption. Fourier-transform infrared spectroscopy (FTIR) analysis identified O-H, C-H, C=O, and C-O as the principal functional groups participating in the cell wall adsorption process. These investigations establish a scientific foundation for the prospective application of this strain as an efficient biological detoxification agent in food and feed safety management systems. Full article

Amylosucrase (AS) is a highly versatile enzyme with significant potential for industrial applications, including functional food production and glycosylation of bioactive compounds. However, its large-scale production is hampered by low secretion efficiency in microbial hosts. This study focuses on engineering the twin-arginine translocation (TAT) pathway and optimizing membrane resource allocation in Bacillus licheniformis to enhance the extracellular production of Neisseria polysaccharea amylosucrase (NpAS). The investigation integrates three targeted strategies: optimizing the hydrophobic region adjacent to the TAT signal peptide, modifying TAT translocases via site-directed mutagenesis, and improving inter-pathway membrane resource redistribution by deleting non-essential Sec pathway components. Among the engineered strains, BLΔDF93S-2.0AS1 achieved an extracellular enzyme activity of 706.10 U/L, equating to a 2.01-fold improvement over the parental strain. These results emphasize the potential of combining multifaceted engineering strategies to optimize heterologous protein secretion systems. Full article

Bacillus licheniformis (B. licheniformis) is a probiotic known for its ability to enhance host resistance against pathogenic infections. This study aimed to evaluate the protective effects and underlying mechanisms of B. licheniformis in a mouse model challenged with Clostridium perfringens (C. perfringens). C57BL/6J mice were pretreated with B. licheniformis for 21 days before oral infection with C. perfringens. The probiotic administration significantly prevented infection-induced weight loss and immune organ enlargement. Serum cytokine analysis revealed that B. licheniformis increased anti-inflammatory IL-4 and IL-10 levels while reducing pro-inflammatory IL-1β, IL-6, and TNF-α levels. Histological analysis showed that B. licheniformis preserved intestinal morphology and inhibited epithelial cell apoptosis. Moreover, the probiotic mitigated the infection-induced decline in volatile fatty acid (VFA) production. 16S rRNA gene sequencing revealed that B. licheniformis reshaped the cecal microbiota, characterized by the increased abundance of Lachnospiraceae_NK4A136_group, Muribaculaceae, and Parabacteroides, and reduced abundance of Alistipes. Untargeted metabolomic profiling identified differential metabolites—including D-glucono-1,5-lactone, D-erythrose 4-phosphate, and D-sedoheptulose 7-phosphate—enriched in the pentose phosphate pathway, suggesting a regulatory role in redox homeostasis and host response. Collectively, these results indicate that B. licheniformis exerts protective effects against C. perfringens infection by modulating inflammation, apoptosis, microbial composition, and metabolic pathways. This work provides new insights into the application of B. licheniformis as a functional microbial feed additive in livestock disease prevention. Full article

Geosmin (GSM) and 2-methylisoborneol (2-MIB), microbial-derived terpenoid compounds prevalent in aquaculture systems, impair fillet quality and disrupt physiological homeostasis in aquatic species by inducing oxidative stress and lipid peroxidation. Despite their significant impact, effective strategies for eliminating these compounds from fish tissues remain underexplored. In this study, we employed primer-mediated PCR amplification to identify strains that produce 2-MIB and GSM and evaluated the efficacy of Bacillus licheniformis strain BL23 (BL23) in suppressing S. thermocarboxydus (ST), a key contributor to terpenoid synthesis. Experimental fish were allocated to three groups (n = 30 per group): Group C (control, standard feed), Group T1 (BL23-supplemented feed), and Group T2 (BL23 + ST coculture). Probiotic concentrations in the tanks were maintained at 10⁶ CFU/mL under controlled conditions (30 °C). Tissue and aqueous samples were collected at intervals for the analysis of texture, growth performance, and terpenoid concentrations, with measurements in triplicate. Subsequently, B. licheniformis strain BL23 (BL23), which exhibits inhibitory effects against S. thermocarboxydus (ST) growth, was cultured and introduced into both fish specimens and aqueous systems. The outcomes of strain inoculation and cultivation experiments demonstrated the emergence of an inhibition zone surrounding the actinomycetes inoculated with BL23. The results from liquid coculture assays revealed a reduction in the concentration of ST from 10⁶ CFU/mL at 48 h to 10¹ CFU/mL at 72 h post-coculture with BL23 for an initial 48 h period. An analysis of fish tissue and aqueous samples confirmed that BL23 exhibited a significant inhibitory effect on the growth of ST, leading to a substantial decrease in GSM content (p < 0.05). However, no statistically significant improvements were observed in fish growth performance (weight gain, feed conversion rate) or meat texture quality parameters (hardness, elasticity). These findings present a novel approach to mitigating geosmin-induced off-flavors in aquaculture products, highlighting its potential utility in water management and aquatic food production systems. The results are particularly pertinent for the development of biological control strategies targeting microbial-derived odorants in recirculating aquaculture systems. Full article

This study isolated five acid-producing strains (XQ₁ and YZ₁–YZ₄) from naturally fermented pomace of Rosa roxburghii Tratt (RRT) in Guizhou’s karst region. Genetic and phenotypic analyses identified XQ₁, YZ₂, and YZ₄ as Lactobacillus plantarum (L. plantarum), YZ₃ as Weissella cibaria, and YZ₁ as Bacillus licheniformis. A comparative evaluation with commercial strain AC revealed that XQ₁, YZ₂, and YZ₄ exhibited superior acidification (reaching the stationary phase at 40 h) and tolerance to acidic conditions (pH 3.0), ethanol (6% v/v), bile salts (0.3%), and osmotic stress (6.5% NaCl), along with broad-spectrum antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Shigella dysenteriae, and Pseudomonas aeruginosa. Their cell-free supernatants (CFSs) showed comparable superoxide dismutase activity and total antioxidant capacity (2.54–2.66 FeSO₄·7H₂O eq mmol/L) to AC (2.68), with DPPH radical scavenging exceeding 50%. YZ₃ displayed weaker acid production, tolerance, and limited antimicrobial effects. Safety assessments confirmed non-hemolytic activity and antibiotic susceptibility. In conclusion, the L. plantarum strains XQ₁, YZ₂, and YZ₄ demonstrated strong ensiling potential and remarkable probiotic properties, establishing them as promising indigenous microbial resources for the preservation of RRT pomace and other food products. Full article

Cotton stalks, a major agricultural byproduct, are challenging to decompose naturally; however, they can be transformed into valuable animal feed through microbial fermentation. This study identifies Aspergillus niger HQXY as the most efficient cellulase-producing strain out of six evaluated strains, using it to ferment cotton stalks and significantly degrade cellulose and hemicellulose. By optimizing solid-state fermentation conditions via response surface methodology, the crude fiber content of the cotton stalks was reduced by 34%. A novel sequential co-fermentation approach combining Aspergillus niger with probiotics (Bacillus licheniformis, Candida utilis, and Lactobacillus casei) further enhanced the feed’s nutritional profile. The optimal results were obtained using a 1:1:1 ratio of strains (Aspergillus niger, Bacillus licheniformis, and Lactobacillus casei) at a 8% inoculation rate over 30 days. This co-fermentation strategy lowered the pH and reduced gossypol to 15.5 mg·kg⁻¹. The findings highlight the effectiveness of Aspergillus niger HQXY and probiotics in improving the quality of cotton stalks, by reducing crude fiber and gossypol content, thus offering a promising method for the sustainable utilization of agricultural waste as high-quality animal feed. Full article

Background/Objectives: Clostridioides difficile infection (CDI) is an important nosocomial diarrheal disease. The benefits of the probiotic Bacillus licheniformis (B. licheniformis) in the preservation of intestinal microbiota have not been studied in patients with CDI to date. Therefore, we aimed to investigate the efficacy of B. licheniformis in preserving the intestinal microbiota in patients with CDI. Methods: A multicenter, randomized, placebo-controlled trial was carried out at six academic centers in Korea. Individuals diagnosed with mild to moderate CDI were included in this trial. CDI was treated with vancomycin 125 mg four times daily for two weeks. Along with vancomycin, B. licheniformis was administered for five days in this study, while a placebo was given to the placebo group. Microbiome analysis was performed before and five days after administering vancomycin and B. licheniformis or placebo, using 16S rRNA amplicon sequencing. Alpha and beta diversity was compared between the two groups. Results: A total of 35 participants were finally included in this study, with 16 in the study group and 19 in the placebo group. The alpha diversity was similar in both groups before CDI treatment. After five days of the administration of vancomycin and B. licheniformis or placebo, alpha diversity did not decrease in the study group (Chao1 index, p = 0.665; observed features, p = 0.692). In contrast, alpha diversity decreased in the placebo group (Chao1 index, p = 0.011; observed features, p = 0.011). Beta diversity did not differ between the two groups. Conclusions: The addition of B. licheniformis to vancomycin was effective in preserving gut microbiota in patients with CDI. Full article

Sea cucumbers are valuable in aquaculture, but their cultivation faces challenges from diseases such as skin ulceration syndrome caused by Vibrio alginolyticus (VA). This study aimed to isolate and identify probiotics capable of combating VA and improving sea cucumber’s growth performance. Pathogenic VA was identified, through 16S rDNA sequencing, confirming its high genetic similarity (>99%) to Vibrio alginolyticus. Two Bacillus strains, Bacillus licheniformis YB-1, and Bacillus megaterium YB-2, were isolated as potential probiotics, with identification supported by 16S rDNA phylogenetic analysis and deposition in microbial culture collections. They demonstrated strong antibacterial activity against VA in vitro without exhibiting antagonism when combined. Probiotic tolerance to environmental stressors was observed, while feeding trials revealed significant growth improvements in sea cucumbers, with the highest specific growth rates observed at 1 × 10⁶ CFU/mL for both strains. Immersion challenge tests showed that sea cucumbers treated with probiotics exhibited reduced symptoms of rotten skin syndrome and higher survival rates. The optimal combination of YB-1 and YB-2, with viable bacteria concentrations of 5 × 10⁷ CFU/mL each, achieved a 55% survival rate after a VA challenge, demonstrating their synergistic efficacy. These findings suggest that YB-1 and YB-2 offer promising probiotic solutions for enhancing sea cucumber health and resistance to VA infections in aquaculture. Full article

Twenty-four Girolando cows (107 ± 56 days in milk, milk yield 22.0 ± 10.25 kg/d, and 529 ± 103 kg body weight) were used in a completely randomized design. The cows were divided according to the following experimental diets: 1—CON (basal diet with ground dry corn) 2—RCS (diet with total replacement of ground corn by rehydrated corn grain silage) 3—RCSP (diet with total replacement of ground corn by rehydrated corn grain silage + 500 g ton⁻¹ of CINBENZA DP100^®, NOVUS International, Inc (Chesterfield, Missouri, U.S.A.). enzymatic extract of Bacillus licheniformis, protease activity 600 IU g⁻¹). Cows fed RCS + RCSP showed higher DMI, milk yield, and better efficiency (MY/DMI) compared to animals fed CON diet. Cows fed the CON diet had higher fecal concentration, and lower total starch digestibility and milk protein content compared to animals supplemented with RCS + RCSP. Cows fed RCSP showed a 2.96% superiority in total starch digestibility compared to animals fed RCS. Animals supplemented with RCSP presented higher milk yield (17.45%) and milk fat content (13.76%) than cows fed RCS. The inclusion of protease in rehydrated corn silage improved dairy cow performance, enhancing dry matter intake, milk yield, and productive efficiency. It also increased starch digestibility and milk protein and fat content, optimizing nutrient utilization. Full article

The structural diversity of marine natural products is considered a potential resource for the pharmaceutical industry. In our study of marine-derived compounds, one bacterium Bacillus licheniformis S-1 was discovered to have the ability to produce bioactive natural products. After a further chemistry investigation, one novel 4-aminopyridinium derivative, 4-(dimethylamino)-1-(2S-((4hydroxybenzoyl)oxy)propyl)pyridin-1-ium (1), along with 15 known cyclic dipeptides (2–16) were isolated from the bacterium B. licheniformis S-1 derived from a shallow sea sediment. The structures of compounds 1–16 were elucidated through comprehensive NMR spectroscopic and specific optical rotation (OR) data analyses. Compound 6 showed antibacterial activity against Pseudomonas fulva with an MIC value of 50 µg/mL. This is the first study to discover a pyridinium derivative and cyclic dipeptides from B. licheniformis. Full article

The Gran Desierto de Altar, located in Sonora, Mexico, represents an arid region that offers an opportunity to study microbial life under extreme conditions. This study analyzed the bacterial diversity present in two distinct types of desert sediments: sand dunes (SDs) and salt crusts (SCs) by culture-dependent and culture-independent methods. Environmental DNA was obtained for 16S rRNA gene amplicon sequencing to obtain taxonomic information using QIIME2. In SD, the bacterial communities comprised 24 phyla, with Actinobacteriota (30–40%), Proteobacteria (22–27%), Bacteroidota (9–11%), Firmicutes (7–10%), and Chloroflexi (3–6%) emerging as the most abundant. Notably, in SC, the archaeal phylum Halobacterota was predominant (37–58%). SC hosted 12 bacterial phyla, the most abundant being Firmicutes (14–30%), Bacteroidota (3–24%), and Proteobacteria (1–12%). Bacteria belonging to the phylum Firmicutes, including Metabacillus niabensis, Bacillus subtilis, Bacillus licheniformis, and Alkalibacillus haloalkaliphilus, were isolated using nutrient and saline media. Overall, our findings indicate that the taxonomic composition of the samples analyzed from the Gran Desierto de Altar is consistent with that found in arid environments worldwide. This study provides a basis for future studies focusing on microbial diversity, genetic potentials, and resistance mechanisms of microorganisms from arid environments. Full article

Bee colonies are constantly threatened by a bacterial larvae disease called American foulbrood, caused by the Gram-positive bacterium Paenibacillus larvae. This is a highly specialized pathogen with only one established host, the honey bee larvae. The current state of legislation throughout the European Union prevents the inclusion of pharmacotherapy treatment, and the only control is based on the physical elimination of infected colonies upon veterinary orders. The purpose of this study was to investigate the antimicrobial activity of selected bacteria with proven probiotic potential with typical characteristics meeting the definition of a probiotic that could reduce the American foulbrood pressure by promoting the development of the larvae microbiome that competes with and blocks the excessive proliferation and production of P. larvae endospores. The antimicrobial activity of inoculants of the following selected strains was studied: Bacillus pumilus, Bacillus licheniformis, Streptomyces narbonensis, Lysinibacillus fusiformis, Levilactobacillus brevis, Bacillus megaterium against Paenibacillus larvae ATCC 9545 (formerly Paenibacillus larvae sub sp. larvae), and Paenibacillus larvae CCUG 48973. Analyses were performed by the well diffusion method according to EUCAST standards (clinical breakpoints and dosing of antibiotics) with modifications due to the specificity of the bacteria used. The largest zone of growth inhibition of P. larvae was confirmed with S. narbonensis, B. licheniformis, and B. megaterium, and medium activity was observed with L. brevis and B. pumilus. Negligible activity was shown by L. fusiformis. Differences were noticed in the resistance of indicator strains of P. larvae and between the media and carriers used. Full article

Poly-γ-glutamic acid (γ-PGA) is a natural polymer whose molecular weight and viscosity are critical for its application in various fields. However, research on super-high-molecular-weight or -viscosity γ-PGA is limited. In this study, the pgdS gene in Bacillus licheniformis WX-02 was knocked out using homologous recombination, and the batch fermentation performances of the recombinant strain WX-ΔpgdS were compared to those of WX-02. Nitrate accumulation was observed in the early fermentation stages of WX-ΔpgdS, and gene transcription analysis and cell morphology observations revealed that nitrite accumulation was caused by oxygen limitation due to cell aggregation. When the aeration and agitation rates were increased to 2.5 vvm and 600 r/min, respectively, and citrate was used as a precursor, nitrite accumulation was alleviated in WX-ΔpgdS fermentation broth, while γ-PGA yield and broth viscosity reached 17.3 g/L and 4988 mPa·s. Scanning electron microscopy (SEM) showed that the γ-PGA produced by WX-ΔpgdS exhibited a three-dimensional porous network structure. At a γ-PGA concentration of 5 mg/L, the fermentation broth of WX-ΔpgdS achieved a flocculation efficiency of 95.7% after 30 min of microalgae settling. These findings demonstrate that pgdS knockout results in super-high-viscosity γ-PGA, positioning it as an eco-friendly and cost-effective biocoagulant for microalgae harvesting. Full article

Using a Taguchi experimental design, this research focuses on utilizing indigenous bacteria from the Danube River to enhance the self-healing capabilities and structural integrity of cementitious materials. Bacillus licheniformis and Bacillus muralis were used as individual bacterium or in co-culture, with a concentration of 8 logs CFU, while the humidity variation involved testing wet and wet–dry conditions. Additionally, artificial neural network (ANN) modeling of the compressive strength of cement samples results in improvements in compressive strength, particularly under wet–dry conditions. By inducing targeted bacterial activity, the formation of calcium carbonate precipitates was initiated, which effectively sealed formed cracks, thus restoring and even enhancing the material’s strength. In addition to short-term improvements, this study also evaluates long-term improvements, with compressive strength measured over periods extending to 180 days. The results demonstrate sustained self-healing capabilities and strength improvements under varied environmental conditions, emphasizing the potential for long-term application in real-world infrastructure. This study also explores the role of environmental conditions, such as wet and wet–dry cycles, in optimizing the self-healing process, revealing that cyclic exposure conditions further improve the efficiency of strength recovery. The findings suggest that autochthonous bacterial co-cultures can be a viable solution for enhancing the durability and lifespan of concrete structures. This research provides a foundation for further exploration into bio-based self-healing mechanisms and their practical applications in the concrete industry. Full article