Yongmei Zhang

Spore-forming Bacillus coagulans has been widely recognized as an important probiotic, which is commonly used in products for human consumption and animal feeds. B. coagulans exhibits beneficial traits from both Bacillus and lactic acid-producing Lactobacillus. The present study evaluated the safety of the newly isolated B. coagulans strain JBI-YZ6.3, using combined genomic and phenotypic analysis approaches. The taxonomic classification based on genome sequence and biochemical tests identified strain JBI-YZ6.3 as B. coagulans. Comprehensive genome-based analyses established JBI-YZ6.3 as a novel strain of B. coagulans. Antibiotic susceptibility testing showed that the strain JBI-YZ6.3 was sensitive to a panel of fourteen antibiotics, and no genes related to antibiotic resistance were found in its genome. The spores of strain JBI-YZ6.3 exhibited tolerance to acid and bile salts, as well as stability at ambient and elevated conditions of temperature and relative humidity. There were no homologs of Bacillus toxin genes identified in the genome of JBI-YZ6.3, and the strain exhibited no cytotoxicity towards Vero cells and human peripheral blood mononuclear cells. In conclusion, findings from this study support the safety of B. coagulans strain JBI-YZ6.3, which can be developed into new probiotic products for preventive and therapeutic benefits in human and animal hosts.

Bacillus coagulans strain JBI-YZ6.3 is a safe probiotic bacterium isolated from food-grade tapioca starch. The complete genome of B. coagulans JBI-YZ6.3 comprises one circular chromosome of 3.5 Mb and contains no toxigenic and antibiotic resistance genes, providing molecular information to support the strain’s safety and usage as a probiotic.