Bacillus subtilis SOM8 isolated from sesame oil meal for potential probiotic application in inhibiting human enteropathogens.

2024-03-28
BMC microbiology 24(1)
- Zhongtian Zhao
- Wenrui Li
- The Thien Tran
- Say Chye Joachim Loo

PubMed: 38539071
DOI: 10.1186/s12866-024-03263-y

Study Design

Population: prospective probiotics from homogenised food waste - sesame oil meal (SOM)
Methods: implemented a funnel-shaped approach to isolate and evaluate prospective probiotics from homogenised food waste - sesame oil meal (SOM); of nine isolated strains with antipathogenic properties, B. subtilis SOM8 was selected for further comprehensive assessment

Background

While particular strains within the Bacillus species, such as Bacillus subtilis, have been commercially utilised as probiotics, it is critical to implement screening assays and evaluate the safety to identify potential Bacillus probiotic strains before clinical trials. This is because some Bacillus species, including B. cereus and B. anthracis, can produce toxins that are harmful to humans.

Results

In this study, we implemented a funnel-shaped approach to isolate and evaluate prospective probiotics from homogenised food waste - sesame oil meal (SOM). Of nine isolated strains with antipathogenic properties, B. subtilis SOM8 displayed the most promising activities against five listed human enteropathogens and was selected for further comprehensive assessment. B. subtilis SOM8 exhibited good tolerance when exposed to adverse stressors including acidity, bile salts, simulated gastric fluid (SGF), simulated intestinal fluid (SIF), and heat treatment. Additionally, B. subtilis SOM8 possesses host-associated benefits such as antioxidant and bile salt hydrolase (BSH) activity. Furthermore, B. subtilis SOM8 contains only haemolysin toxin genes but has been proved to display partial haemolysis in the test and low cytotoxicity in Caco-2 cell models for in vitro evaluation. Moreover, B. subtilis SOM8 intrinsically resists only streptomycin and lacks plasmids or other mobile genetic elements. Bioinformatic analyses also predicted B. subtilis SOM8 encodes various bioactives compound like fengycin and lichendicin that could enable further biomedical applications.

Conclusions

Our comprehensive evaluation revealed the substantial potential of B. subtilis SOM8 as a probiotic for targeting human enteropathogens, attributable to its exceptional performance across selection assays. Furthermore, our safety assessment, encompassing both phenotypic and genotypic analyses, showed B. subtilis SOM8 has a favourable preclinical safety profile, without significant threats to human health. Collectively, these findings highlight the promising prospects of B. subtilis SOM8 as a potent probiotic candidate for additional clinical development.

Research Insights

Supplement	Dose	Health Outcome	Effect Type	Effect Size	Source
Bacillus subtilis MB40	—	Improved Antioxidant Activity	Beneficial	Small	View source B. subtilis SOM8 possesses host-associated benefits such as antioxidant and bile salt hydrolase (BSH) activity
Bacillus subtilis MB40	—	Improved Gastrointestinal Pathogen Inhibition	Beneficial	Moderate	View source B. subtilis SOM8 displayed the most promising activities against five listed human enteropathogens
Bacillus subtilis MB40	—	Improved Stress Tolerance	Beneficial	Moderate	View source B. subtilis SOM8 exhibited good tolerance when exposed to adverse stressors including acidity, bile salts, simulated gastric fluid (SGF), simulated intestinal fluid (SIF), and heat treatment
Bacillus subtilis MB40	—	Reduced Cytotoxicity	Beneficial	Small	View source B. subtilis SOM8 has been proved to display partial haemolysis in the test and low cytotoxicity in Caco-2 cell models for in vitro evaluation