Potential application of the probiotic Bacillus licheniformis as an adjuvant in the treatment of diseases in humans and animals: A systematic review

Microbial induce carbonate precipitation derive bio-concrete formation: A sustainable solution for carbon sequestration and eco-friendly construction

The microbial-induced calcium carbonate precipitation (MICP) technique has high potential in the development of bio-concrete, enhancing the strength, durability, and self-healing properties of construction materials. In this review work, we have explored the crucial role of microorganisms in carbon sequestration, microbial methods in CaCO3 synthesis, and the application of bio-concrete formation, based on the SCOPUS database from 2010 to 2024. The production of construction materials consumes a significant amount of energy, which can emit high amounts of carbon dioxide (CO2) into the atmosphere. As a sustainable solution, researchers are working to introduce novel construction biomaterials through MICP, which play a key role in CO2 sequestration to address this issue. Herein, microorganisms (bacteria) can utilize CO2 through multiple absorption processes, converting it into value-added compounds or inducing CaCO3 precipitation. For example, specific bacteria like Bacillus cereus, Bacillus sphaericus, Bacillus pasteurii, Bacillus subtilis, and Bacillus megatherium are known for their capability to thrive in alkaline conditions and play a key role in bio-concrete formation. Furthermore, it has been highlighted that the bio-concrete ability to sequester CO2 through the carbonation process, emphasizes the roles of urease activity and carbonic anhydrase (CA) in bio-concrete. Overall, this paper provides a complete synopsis of recent research on the formation of bio-concrete through MICP and the various elements influencing the technique, including cementation solution, temperature, injection, pH, and bacteria. This suggests that emerging trends in bio-concrete utilization could significantly reduce CO2 emissions while enhancing the strength of non-reinforced concrete.

Five-Day Treatment with B. licheniformis Along with Classical Vancomycin Treatment Was Effective in Preserving Gut Microbiota in Patients with Clostridioides difficile Infection

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.

Navigating a challenging path: precision disease treatment with tailored oral nano-armor-probiotics

Oral probiotics have significant potential for preventing and treating many diseases. Yet, their efficacy is often hindered by challenges related to survival and colonization within the gastrointestinal tract. Nanoparticles emerge as a transformative solution, offering robust protection and enhancing the stability and bioavailability of these probiotics. This review explores the innovative application of nanoparticle-armored engineered probiotics for precise disease treatment, specifically addressing the physiological barriers associated with oral administration. A comprehensive evaluation of various nano-armor probiotics and encapsulation methods is provided, carefully analyzing their respective merits and limitations, alongside strategies to enhance probiotic survival and achieve targeted delivery and colonization within the gastrointestinal tract. Furthermore, the review explores the potential clinical applications of nano-armored probiotics in precision therapeutics, critically addressing safety and regulatory considerations, and proposing the innovative concept of 'probiotic intestinal colonization with nano armor' for brain-targeted therapies. Ultimately, this review aspires to guide the advancement of nano-armored probiotic therapies, driving progress in precision medicine and paving the way for groundbreaking treatment modalities.

Probiotic Bacillus licheniformis DSMZ 28710 improves sow milk microbiota and enhances piglet health outcomes

Maintaining a diverse and balanced sow milk microbiome is essential to piglet development. Thus, this study aimed to examine the effects of probiotic Bacillus licheniformis supplementation on the microbiome composition of sow colostrum and milk, and to review associated health findings in piglets. B. licheniformis DSMZ 28710 was supplemented at 10 g/day as feed additive before predicted farrowing until weaning by top dressing. Colostrum and milk samples were collected for metagenomic DNA extraction, 16s rRNA sequencing, and bioinformatics analyses for bacterial microbiota diversity. Results indicated that the supplementation increased the abundances of beneficial bacteria, such as Lactobacillus, Pediococcus, Bacteroides, and Bifidobacterium, while decreasing the abundances of pathogenic bacteria, such as Staphylococcus aureus, Enterobacteriaceae, and Campylobacter in the colostrum. The supplementation increased diversity while maintaining richness and evenness. Moreover, the rise in predicted microbial community metabolic function in membrane transport pathways provides crucial evidence showing that the supplementation is potentially beneficial to piglets, as these pathways are important for providing nutrients and immunity to offspring. This research highlights the importance of microbiome composition in sow milk and the potential of B. licheniformis supplementation as a means to improve piglet health and development.

The Bacteriocins Produced by Lactic Acid Bacteria and the Promising Applications in Promoting Gastrointestinal Health

Bacteriocins produced by lactic acid bacteria (LAB) are promising bioactive peptides. Intriguingly, bacteriocins have health benefits to the host and may be applied safely in the food industry as bio-preservatives or as therapeutic interventions preventing intestinal diseases. In recent years, finding a safe alternative approach to conventional treatments to promote gut health is a scientific hotspot. Therefore, this review aimed to give insight into the promising applications of LAB-bacteriocins in preventing intestinal diseases, such as colonic cancer, Helicobacter pylori infections, multidrug-resistant infection-associated colitis, viral gastroenteritis, inflammatory bowel disease, and obesity disorders. Moreover, we highlighted the recent research on bacteriocins promoting gastrointestinal health. The review also provided insights into the proposed mechanisms, challenges and opportunities, trends and prospects. In addition, a SWOT analysis was conducted on the potential applications. Based on properties, biosafety, and health functions of LAB-bacteriocins, we conclude that the future applications of LAB-bacteriocins are promising in promoting gastrointestinal health. Further in vivo trials are needed to confirm these potential effects of LAB-bacteriocins interventions.

Is there a role for intestinal sporobiota in the antimicrobial resistance crisis?

Antimicrobial resistance (AMR) is a complex issue requiring specific, multi-sectoral measures to slow its spread. When people are exposed to antimicrobial agents, it can cause resistant bacteria to increase. This means that the use, misuse, and excessive use of antimicrobial agents exert selective pressure on bacteria, which can lead to the development of "silent" reservoirs of antimicrobial resistance genes. These genes can later be mobilized into pathogenic bacteria and contribute to the spread of AMR. Many socioeconomic and environmental factors influence the transmission and dissemination of resistance genes, such as the quality of healthcare systems, water sanitation, hygiene infrastructure, and pollution. The sporobiota is an essential part of the gut microbiota that plays a role in maintaining gut homeostasis. However, because spores are highly transmissible and can spread easily, they can be a vector for AMR. The sporobiota resistome, particularly the mobile resistome, is important for tracking, managing, and limiting the spread of antimicrobial resistance genes among pathogenic and commensal bacterial species.

Prevention of Radiotherapy-Induced Enteropathy by Probiotics (PREP): Double-Blind Randomized Placebo-Controlled Trial

Probiotics are thought to be effective in the treatment of radiation-induced enteropathy (RIE). However, little is known regarding their efficacy in preventing RIE. In this prospective, randomized, double-blinded, placebo-controlled, single-center study, the incidence of grade 2 acute RIE was compared and the safety of probiotics was evaluated. Patients receiving pelvic radiotherapy for a minimum of 40 Gy at the pelvic level were randomized into two groups: (i) a probiotic group receiving Bacillus licheniformis from two weeks before radiotherapy until the end and (ii) a control group receiving a placebo with the same schedule. The toxicities of 234 patients were graded according to the Common Terminology Criteria for Adverse Events v5.0. Grade 1 RIE was observed in 65 (56%) of the probiotics group compared with 75 (64%) of the placebo group. Grade 2 RIE occurred in 30 patients (26%) in the probiotics group compared with 26 (22%) in the placebo group, indicating that probiotics failed in their preventive role compared with placebo (p = 0.493). Medication adherence rates were good, and no difference was observed between the two arms. These findings suggest that B. licheniformis does not significantly prevent RIE.

Bacillus altitudinis 1.4 genome analysis-functional annotation of probiotic properties and immunomodulatory activity

Probiotics are live microorganisms that, when administered in adequate quantities, provide health benefits to the host. In this study, phenotypic and genotypic methods were used to evaluate the probiotic properties of Bacillus altitudinis 1.4. The isolate was sensitive to all antimicrobials tested and presented a positive result in the hemolysis test. B. altitudinis 1.4 spores were more resistant than vegetative cells, when evaluated in simulation of cell viability in the gastrointestinal tract, as well as adhesion to the intestinal mucosa. The isolate was capable of self-aggregation and coaggregation with pathogens such as Escherichia coli ATCC 25922 and Salmonella Enteritidis ATCC 13076. Genomic analysis revealed the presence of genes with probiotic characteristics. From this study it was possible to evaluate the gene expression of pro-inflammatory and anti-inflammatory cytokines for different treatments. Viable vegetative cells of B. altitudinis 1.4 increased the transcription of pro-inflammatory factors, in addition to also increasing the transcription of IL-10, indicating a tendency to stimulate a pro-inflammatory profile. Given the results presented, B. altitudinis 1.4 showed potential to be applied in the incorporation of this microorganism into animal feed, since the spores could tolerate the feed handling and pelletization processes.

Multi-omic analysis reveals that Bacillus licheniformis enhances pekin ducks growth performance via lipid metabolism regulation

Introduction: Bacillus licheniformis (B.licheniformis) was widely used in poultry feeds. However, it is still unclear about how B.licheniformis regulates the growth and development of Pekin ducks. Methods: The experiment was designed to clarify the effect and molecular mechanism of B. licheniformis on the lipid metabolism and developmental growth of Pekin ducks through multiomics analysis, including transcriptomic and metabolomic analyses. Results: The results showed that compared with the control group, the addition of 400 mg/kg B. licheniformis could significantly increase the body weight of Pekin ducks and the content of triglyceride (p < 0.05), at the same time, the addition of B. licheniformis could affect the lipid metabolism of liver in Pekin ducks, and the addition of 400 mg/kg B. licheniformis could significantly increase the content of lipoprotein lipase in liver of Pekin ducks. Transcriptomic analysis revealed that the addition of B. licheniformis primarily impacted fatty acid and glutathione, amino acid metabolism, fatty acid degradation, as well as biosynthesis and elongation of unsaturated fatty acids. Metabolomic analysis indicated that B. licheniformis primarily affected the regulation of glycerol phospholipids, fatty acids, and glycerol metabolites. Multiomics analysis demonstrated that the addition of B. licheniformis to the diet of Pekin ducks enhanced the regulation of enzymes involved in fat synthesis via the PPAR signaling pathway, actively participating in fat synthesis and fatty acid transport. Discussion: We found that B. licheniformis effectively influences fat content and lipid metabolism by modulating lipid metabolism-associated enzymes in the liver. Ultimately, this study contributes to our understanding of how B. licheniformis can improve the growth performance of Pekin ducks, particularly in terms of fat deposition, thereby providing a theoretical foundation for its practical application. Conclusion: B. licheniformis can increase the regulation of enzymes related to fat synthesis through PPAR signal pathway, and actively participate in liver fat synthesis and fatty acid transport, thus changing the lipid metabolism of Pekin ducks, mainly in the regulation of glycerol phospholipids, fatty acids and glycerol lipid metabolites.

A review on the alternatives to antibiotics and the treatment of antibiotic pollution: Current development and future prospects

Antibiotics, widely used in the fields of medicine, animal husbandry, aquaculture, and agriculture, pose a serious threat to the ecological environment and human health. To prevent antibiotic pollution, efforts have been made in recent years to explore alternative options for antibiotics in animal feed, but the effectiveness of these alternatives in replacing antibiotics is not thoroughly understood due to the variation from case to case. Furthermore, a systematic summary of the specific applications and limitations of antibiotic removal techniques in the environment is crucial for developing effective strategies to address antibiotic contamination. This comprehensive review summarized the current development and potential issues on different types of antibiotic substitutes, such as enzyme preparations, probiotics, and plant extracts. Meanwhile, the existing technologies for antibiotic residue removal were discussed under the scope of application and limitation. The present work aims to highlight the strategy of controlling antibiotics from the source and provide valuable insights for green and efficient antibiotic treatment.

Halophilic lactic acid bacteria - Play a vital role in the fermented food industry

Halophilic lactic acid bacteria have been widely found in various high-salt fermented foods. The distribution of these species in salt-fermented foods contributes significantly to the development of the product's flavor. Besides, these bacteria also have the ability to biosynthesize bioactive components which potentially apply to different areas. In this review, insights into the metabolic properties, salt stress responses, and potential applications of these bacteria have been have been elucidated. The purpose of this review highlights the important role of halophilic lactic acid bacteria in improving the quality and safety of salt-fermented products and explores the potential application of these bacteria.

Molecular identification and safety assessment of the potential probiotic strain Bacillus paralicheniformis HMPM220325 isolated from artisanal fruit dairy products

Bacillus probiotics exhibit considerable economic potential owing to their heightened resilience to external stressors and relatively lower costs related to production and preservation. Although Bacillus paralicheniformis has been acknowledged as a plant-promoting bacterium for a long time, understanding its potential as a probiotic is still in its nascent stages. In this study, the safety and probiotic characteristics of a strain of HMPM220325, isolated from artisanal fruit dairy products, were examined through whole-genome sequencing and phenotypic analysis. The whole genome of HMPM220325 was analyzed for antimicrobial resistance genes, pathogenicity factors, and genes associated with probiotic traits including stress resistance, spore formation, gut adhesion, competitive exclusion of pathogens, bacteriocin expression, and carbohydrate metabolism related to prebiotic utilization. Also, wet lab experiments were conducted for the characterization of probiotics. The identification of the organism as B. paralicheniformis was verified. Its safety was assessed through in silico analysis, the haemolytic activity test, and the acute oral toxicity test. B. paralicheniformis HMPM220325 demonstrated its ability to survive in the pH range of 4-10 and bile salt concentrations of 0-0.9% (w/v), tolerate temperatures between 20 and 60 °C, and exhibit a robust antioxidant capacity. Moreover, B. paralicheniformis HMPM220325 demonstrated a moderate level of hydrophobicity, had the ability to form biofilms, achieved a self-aggregation rate of 51.77 ± 1.01% within 6 hours, and successfully colonized the mouse intestine for a duration of up to 17 days. Additionally, the genome of B. paralicheniformis HMPM220325 contains three gene clusters associated with the biosynthesis of bacteriocins and exhibits co-aggregation with Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella enterica serovar Typhimurium. The findings of the genomic analysis align with those obtained from the experimental investigation, thereby substantiating the potential of B. paralicheniformis HMPM220325 as a probiotic suitable for incorporation in dairy functional foods and feed applications.

Rumen microbiome-driven insight into bile acid metabolism and host metabolic regulation

Gut microbes play a crucial role in transforming primary bile acids (BAs) into secondary forms, which influence systemic metabolic processes. The rumen, a distinctive and critical microbial habitat in ruminants, boasts a diverse array of microbial species with multifaceted metabolic capabilities. There remains a gap in our understanding of BA metabolism within this ecosystem. Herein, through the analysis of 9371 metagenome-assembled genomes and 329 cultured organisms from the rumen, we identified two enzymes integral to BA metabolism: 3-dehydro-bile acid delta4,6-reductase (baiN) and the bile acid:Na + symporter family (BASS). Both in vitro and in vivo experiments were employed by introducing exogenous BAs. We revealed a transformation of BAs in rumen and found an enzyme cluster, including L-ribulose-5-phosphate 3-epimerase and dihydroorotate dehydrogenase. This cluster, distinct from the previously known BA-inducible operon responsible for 7α-dehydroxylation, suggests a previously unrecognized pathway potentially converting primary BAs into secondary BAs. Moreover, our in vivo experiments indicated that microbial BA administration in the rumen can modulate amino acid and lipid metabolism, with systemic impacts underscored by core secondary BAs and their metabolites. Our study provides insights into the rumen microbiome's role in BA metabolism, revealing a complex microbial pathway for BA biotransformation and its subsequent effect on host metabolic pathways, including those for glucose, amino acids, and lipids. This research not only advances our understanding of microbial BA metabolism but also underscores its wider implications for metabolic regulation, offering opportunities for improving animal and potentially human health.

Bacillus licheniformis bloodstream infections associated with oral probiotic administration: Two case reports

Bacillus licheniformis is a facultative anaerobe, gram-positive, endogenous, spore-forming bacillus. It is included in a probiotic preparation commonly used in clinical practice and is usually safe for oral administration. In this paper, we report two cases of bloodstream infection resulting from using B. licheniformis probiotic preparations for gastrointestinal bleeding. The results suggest that B. licheniformis should be used with caution in people who are immunocompromised and suffering from severe= damage to the intestinal mucosal barrier.

Extracellular nanovesicles produced by Bacillus licheniformis: A potential anticancer agent for breast and lung cancer

Cancer is a major public burden and leading cause of death worldwide; furthermore, it is a significant barrier to increasing life expectancy in most countries of the world. Among various types of cancers, breast and lung cancers lead to significant mortality in both males and females annually. Bacteria-derived products have been explored for their use in cancer therapy. Although bacteria contain significant amounts of anticancer substances, attenuated bacteria may still pose a potential risk for infection owing to the variety of immunomodulatory molecules present in the parental bacteria; therefore, non-cellular bacterial extracellular vesicles (BEVs), which are naturally non-replicating, safer, and are considered to be potential anticancer agents, are preferred for cancer therapy. Gram-positive bacteria actively secrete cytoplasmic membrane vesicles that are spherical and vary between 10 and 400 nm in size. However, no studies have considered cytoplasmic membrane vesicles derived from Bacillus licheniformisin cancer treatment. In this study, we investigated the potential use of B. licheniformis extracellular nanovesicles (BENVs) as therapeutic agents to treat cancer. Purified BENVs from the culture supernatant of B. licheniformis using ultracentrifugation and ExoQuick were characterized using a series of analytical techniques. Human breast cancer cells (MDA-MB-231) and lung cancer cells (A549) were treated with different concentrations of purified BENVs, which inhibited the cell viability and proliferation, and increased cytotoxicity in a dose-dependent manner. To elucidate the mechanism underlying the anticancer activity of BENVs, the oxidative stress markers such as reactive oxygen species (ROS) and glutathione (GSH) levels were measured. The ROS levels were significantly higher in BENV-treated cells, whereas the GSH levels were markedly reduced. Cells treated with BENVs, doxorubicin (DOX), or a combination of BENVs and DOX showed significantly increased expression of p53, p21, caspase-9/3, and Bax, and concomitantly decreased expression of Bcl-2. The combination of BENVs and doxorubicin enhanced mitochondrial dysfunction, DNA damage, and apoptosis. To our knowledge, this is the first study to determine the anticancer properties of BENVs derived from industrially significant probacteria on breast and lung cancer cells.

Bioconversion of feather waste into bioactive nutrients in water by Bacillus licheniformis WHU

Feathers become hazardous pollutants when deposited directly into the environment. The rapid expansion of the poultry industry has significantly increased feather waste, necessitating the development of new ways to degrade and utilize feathers. This study investigated the ability of Bacillus licheniformis WHU to digest intact chicken feathers in water. The results indicated that yields of free amino acids, bioactive peptides, and keratin-derived nano-/micro-particles were improved in bacteria- versus purified keratinase-derived feather hydrolysate. Bacteria-derived feather hydrolysate supplementation induced health benefits in mice, including significantly increased intestinal villus height and zonula occludens-1 protein expression, as well as increased secretory immunoglobulin A levels in the intestinal mucosa and superoxide dismutase activity in serum. Additionally, feather hydrolysate supplementation modulated the mouse gut microbiota, reflected by increased relative abundance of probiotics such as Lactobacillus spp., decreased relative abundance of Proteobacteria at the phylum level and pathogens such as Staphylococcus spp., and increased Bacteroidota/Firmicutes ratio. This study developed a simple, cost-effective method to degrade feathers by B. licheniformis WHU digestion, yielding a hydrolysate that can be directly used as a bioactive nutrient resource. The study findings have applications in the livestock, poultry, and aquaculture industries, which have high demands for cheap protein. KEY POINTS: • Bacillus licheniformis could degrade intact feather in water. • The resulting feather hydrolysate shows prebiotic effects on mouse.

Gas Chromatography-Mass Spectrometry Profiling of Volatile Metabolites Produced by Some Bacillus spp. and Evaluation of Their Antibacterial and Antibiotic Activities

Bacillus species produce different classes of antimicrobial and antioxidant substances: peptides or proteins with different structural compositions and molecular masses and a broad range of volatile organic compounds (VOCs), some of which may serve as biomarkers for microorganism identification. The aim of this study is the identification of biologically active compounds synthesized by five Bacillus species using gas chromatography coupled to mass spectrometry (GC-MS). The current study profoundly enhances the knowledge of antibacterial and antioxidant metabolites ensuring the unambiguous identification of VOCs produced by some Bacillus species, which were isolated from vegetable samples of potato, carrot, and tomato. Phylogenetic and biochemical studies were used to identify the bacterial isolates after culturing. Phylogenetic analysis proved that five bacterial isolates BSS12, BSS13, BSS16, BSS21, and BSS25 showed 99% nucleotide sequence similarities with Bacillus safensis AS-08, Bacillus cereus WAB2133, Bacillus acidiproducens NiuFun, Bacillus toyonesis FORT 102, and Bacillus thuringiensis F3, respectively. The crude extract was prepared from bacterial isolates to assess the antibiotic resistance potency and the antimicrobial potential against various targeted multidrug-resistant strains, including yeast strains such as Candida albicans, Candida krusei, and bacterial strains of Enterococcus hirae, Escherichia coli, Klebsiella aerogenes, Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus group B, Streptococcus mutans, Shigella sonnei, Salmonella enteritidis, Serratia marcescens, Pseudomonas aeruginosa, and Proteus vulgaris. GC-MS analysis of bacterial strains found that VOCs from Bacillus species come in a variety of chemical forms, such as ketones, alcohols, terpenoids, alkenes, etc. Overall, 69 volatile organic compounds were identified from five Bacillus species, and all five were found to share different chemical classes of volatile organic components, which have a variety of pharmacological applications. However, eight antibacterial compounds with different concentrations were commonly found in all five species: acetoin, acetic acid, butanoic acid, 2-methyl-, oxime-, methoxy-phenyl, phenol, 1,2-benzenedicarboxylic acid, bis(2-methylpropyl) ester, nonanoic acid, and hexadecanoic acid, methyl. The present study has demonstrated that bacterial isolates BSS25, BSS21, and BSS16 display potent inhibitory effects against Candida albicans, while BSS25, BSS21, and BSS13 exhibit the ability to restrain the growth and activity of Candida krusei. Notably, BSS25 and BSS21 are the only isolates that demonstrate substantial inhibitory activity against Klebsiella aerogenes. This disparity in inhibitory effects could be attributed to the higher concentrations of acetoin in BSS25 and BSS21, whereas BSS16 and BSS13 have relatively elevated levels of butanoic acid, 2-methyl-. Certainly, the presence of acetoin and butanoic acid, 2-methyl-, contributes to the enhanced antibacterial potential of these bacterial strains, in conjunction with other organic volatile compounds and peptides, among other factors. The biology and physiology of Bacillus can be better understood using these results, which can also be used to create novel biotechnological procedures and applications. Moreover, because of its exceptional ability to synthesize and produce a variety of different antibacterial compounds, Bacillus species can serve as natural and universal carriers for antibiotic compounds in the form of probiotic cultures and strains to fight different pathogens, including mycobacteria.

Bacillus subtilis RBT-7/32 and Bacillus licheniformis RBT-11/17 as New Promising Strains for Use in Probiotic Feed Additives

The normal functioning of a gastrointestinal microflora in poultry and livestock is of significant importance, since its imbalance negatively influences an organism's functions. In this study, the UV mutagenesis and selection were used to obtain two Bacillus strains possessing antagonistic activity towards Escherichia coli and Staphylococcus aureus, and their potential as a probiotic feed additive was evaluated. Compared to the parental strains, the ability of B. subtilis RBT-7/32 and B. licheniformis RBT-11/17 strains to suppress E. coli increased by 77 and 63%, respectively; the corresponding ability of these strains to suppress S. aureus increased by 80 and 79%, respectively. RBT-11/17 could not utilize microcrystalline cellulose and carboxymethyl cellulose, whereas cellulolytic activity of RBT-7/32 was doubled compared to the initial strain. The amylolytic activity of new strains was increased by 40%. Cultivation of strains on media containing soybean, pea, and corn meal did not provide any difference in the biomass production compared to the control. The heating of a water suspension of a dried biomass of the strains for 10-20 min at 80 and 100 °C or incubation in water solutions of citric, ascorbic, acetic, and formic acids (pH 3.0) for 3 and 24 h at 40 °C did not provide any negative influence on the spore survivability. Both strains were evaluated for their resistance to a number of veterinary antibiotics. Thus, RBT-7/32 and RBT-11/17 strains have good prospects for use in feed additives.

Molecular dynamics and simulation analysis against superoxide dismutase (SOD) target of Micrococcus luteus with secondary metabolites from Bacillus licheniformis recognized by genome mining approach

Micrococcus luteus, also known as M. luteus, is a bacterium that inhabits mucous membranes, human skin, and various environmental sources. It is commonly linked to infections, especially among individuals who have compromised immune systems. M. luteus is capable of synthesizing the enzyme superoxide dismutase (SOD) as a component of its protective response to reactive oxygen species (ROS). This enzyme serves as a promising target for drug development in various diseases. The current study utilized a subtractive genomics approach to identify potential therapeutic targets from M. luteus. Additionally, genome mining was employed to identify and characterize the biosynthetic gene clusters (BGCs) responsible for the production of secondary metabolites in Bacillus licheniformis (B. licheniformis), a bacterium known for its production of therapeutically relevant secondary metabolites. Subtractive genomics resulted in identification of important extracellular protein SOD as a drug target that plays a crucial role in shielding cells from damage caused by ROS. Genome mining resulted in identification of five potential ligands (secondary metabolites) from B. licheniformis such as, Bacillibactin (BAC), Paenibactin (PAE), Fengycin (FEN), Surfactin (SUR) and Lichenysin (LIC). Molecular docking was used to predict and analyze the binding interactions between these five ligands and target protein SOD. The resulting protein-ligand complexes were further analyzed for their motions and interactions of atoms and molecules over 250 ns using molecular dynamics (MD) simulation analysis. The analysis of MD simulations suggests, Bacillibactin as the probable candidate to arrest the activities of SOD. All the five compounds reported in this study were found to act by directly/indirectly interacting with ROS molecules, such as superoxide radicals (O2-) and hydrogen peroxide (H2O2), and transforming them into less reactive species. This antioxidant activity contributes to its protective effects against oxidative stress-induced damage in cells making them likely candidate for various applications, including in the development of antioxidant-based therapies, nutraceuticals, and functional foods.

Transcriptome analysis of Cryptocaryon irritans tomont responding to Bacillus licheniformis treatment

Cryptocaryon irritans is a ciliated obligate parasite that causes cryptocaryonosis (white spot disease) and poses great threat to marine fish farming. In recent years, the use of probiotics protects fish from pathogens, which has been identified as the sustainable and environmentally friendly tool to maintain the health and well-being of the host. Accordingly, Cryptocaryon irritans tomont and probiotic Bacillus strain (B.licheniformis, previously isolated from aquaculture water) were co-cultured to detect whether B. licheniformis has anti-C. irritants effect. The result showed that during 4-day incubation, B. licheniformi with 1 × 107 CFU/mL and 1 × 108 CFU/mL concentration effectively inhibited the incubation of C. irritans tomont, indicating that B. licheniformi could inhibit the transformation from reproductive tomont to infective theront of C. irritans. Later, C. irritans samples in the control (without B. licheniformi supplementation) and 1 × 107 CFU/mL B. licheniformi treatment group were sent for transcriptome analysis. Compare with the control group, a total of 3237 differentially expressed genes were identified, among which 626 genes were up-regulated and 2611 genes were down-regulated in 1 × 107 CFU/mL B. licheniformi group. Further Kyoto Encyclopedia of Genes and Genomes pathways analysis showed that anti-C. irritans mechanism of B. licheniformi was mainly involved in the energy metabolism (carbon metabolism, oxidative phosphorylation, biosynthesis of amino acids), transcription and translation (Ribosomes, spliceosomes, RNA transport, etc), lysosome-based degradation (lysosome, phagosome, protein processing in endoplasmic reticulum) and PI3K-Akt pathways. Our study findings raised the possibility of using marine microorganism B. licheniformi in handling aquaculture associated pathogen C. irritans, and preliminarily clarified the molecular mechanism.

Bacillus licheniformis: A Producer of Antimicrobial Substances, including Antimycobacterials, Which Are Feasible for Medical Applications

Bacillus licheniformis produces several classes of antimicrobial substances, including bacteriocins, which are peptides or proteins with different structural composition and molecular mass: ribosomally synthesized by bacteria (1.4-20 kDa), non-ribosomally synthesized peptides and cyclic lipopeptides (0.8-42 kDa) and exopolysaccharides (>1000 kDa). Different bacteriocins act against Gram-positive or Gram-negative bacteria, fungal pathogens and amoeba cells. The main mechanisms of bacteriocin lytic activity include interaction of peptides with membranes of target cells resulting in structural alterations, pore-forming, and inhibition of cell wall biosynthesis. DNase and RNase activity for some bacteriocines are also postulated. Non-ribosomal peptides are synthesized by special non-ribosomal multimodular peptide synthetases and contain unnatural amino acids or fatty acids. Their harmful effect is due to their ability to form pores in biological membranes, destabilize lipid packaging, and disrupt the peptidoglycan layer. Lipopeptides, as biosurfactants, are able to destroy bacterial biofilms. Secreted polysaccharides are high molecular weight compounds, composed of repeated units of sugar moieties attached to a carrier lipid. Their antagonistic action was revealed in relation to bacteria, viruses, and fungi. Exopolysaccharides also inhibit the formation of biofilms by pathogenic bacteria and prevent their colonization on various surfaces. However, mechanism of the harmful effect for many secreted antibacterial substances remains unknown. The antimicrobial activity for most substances has been studied in vitro only, but some substances have been characterized in vivo and they have found practical applications in medicine and veterinary. The cyclic lipopeptides that have surfactant properties are used in some industries. In this review, special attention is paid to the antimycobacterials produced by B. licheniformis as a possible approach to combat multidrug-resistant and latent tuberculosis. In particular, licheniformins and bacitracins have shown strong antimycobacterial activity. However, the medical application of some antibacterials with promising in vitro antimycobacterial activity has been limited by their toxicity to animals and humans. As such, similar to the enhancement in the antimycobacterial activity of natural bacteriocins achieved using genetic engineering, the reduction in toxicity using the same approach appears feasible. The unique capability of B. licheniformis to synthesize and produce a range of different antibacterial compounds means that this organism can act as a natural universal vehicle for antibiotic substances in the form of probiotic cultures and strains to combat various types of pathogens, including mycobacteria.

Characterization of Bacillus Strains from Natural Honeybee Products with High Keratinolytic Activity and Antimicrobial Potential

Two efficient feather-degrading bacteria were isolated from honeybee samples and identified as Bacillus sonorensis and Bacillus licheniformis based on 16S rRNA and genome sequencing. The strains were able to grow on chicken feathers as the sole carbon and nitrogen sources and degraded the feathers in a few days. The highest keratinase activity was detected by the B. licheniformis CG1 strain (3800 U × mL^-1), followed by B. sonorensis AB7 (1450 U × mL^-1). Keratinase from B. licheniformis CG1 was shown to be active across a wide range of pH, potentially making this strain advantageous for further industrial applications. All isolates displayed antimicrobial activity against Micrococcus luteus; however, only B. licheniformis CG1 was able to inhibit the growth of Mycobacterium smegmatis. In silico analysis using BAGEL and antiSMASH identified gene clusters associated with the synthesis of non-ribosomal peptide synthetases (NRPS), polyketide synthases (PKSs) and/or ribosomally synthesized and post-translationally modified peptides (RiPPs) in most of the Bacillus isolates. B. licheniformis CG1, the only strain that inhibited the growth of the mycobacterial strain, contained sequences with 100% similarity to lichenysin (also present in the other isolates) and lichenicidin (only present in the CG1 strain). Both compounds have been described to display antimicrobial activity against distinct bacteria. In summary, in this work, we have isolated a strain (B. licheniformis CG1) with promising potential for use in different industrial applications, including animal nutrition, leather processing, detergent formulation and feather degradation.