Survival, adhesion and immunomodulatory efficacy of spore-forming probiotic Bacillus coagulans

There is a growing demand for probiotics among consumers based on perceived health benefits. Refrigerated dairy products are the major delivery form for probiotic foods. The colder storage temperatures and rich growth media assist retention of viability for conventionally used probiotic bacteria such as Lactobacillus and Bifidobacterium species. However the ability of Bacillus species to form spores that can withstand harsh conditions encountered during processing, storage and gastric transit without affecting its viability has propelled its incorporation into a wider range of functional food products. Bacillus probiotics have been applied for the treatment of gastrointestinal disorders, vaginal infections and lactose intolerance but mechanistic understanding of action is limited.

In this study, Bacillus coagulans MTCC 5856 spores were characterised for potential probiotic attributes of survival during digestion, adhesion to gastro intestinal lining cells and immunostimulation. Such attributes could account for their claimed probiotic properties and therefore support its incorporation into functional foods

B. coagulans showed excellent survival (over 90%) during a simulated in-vitro digestion with high tolerance to acidic pH and digestive enzymes. Probiotic spores adhered to two human epithelial colonic cell lines HT-29 and LS174T at significant adhesion rates of over 80%. The probiotic spores were shown to be non-cytotoxic towards these cell lines and to exert a pronounced immunomodulatory effects in response to LPS-stimulated inflammation in HT-29 cells.

The excellent gastric stability, adhesion and immunomodulatory properties of B. coagulans spores demonstrated here warrant further efficacy studies. An in-vivo evaluation of effectiveness for ameliorating intestinal ulceration in the spontaneous colitis Winnie mouse model will be undertaken.