genus Bacillus

Bacillus coagulans

Bacillus coagulans is a lactic acid forming bacterial species within the genus Bacillus. The organism was first isolated and described in 1932 and was elaborated in the fifth edition of Bergey’s Manual of Determinative Bacteriology. It was initially considered to be a spore-forming Lactobacillus. Since Bacillus coagulans exhibits characteristics typical of both genera Lactobacillus and Bacillus, its taxonomic position between the families Lactobacillaceae and Bacillaceae was often debated. However, in the seventh edition of Bergey’s, it was finally transferred to the genus Bacillus. DNA-based technology was used in distinguishing between the two genera of bacteria which are morphologically similar and possess similar physiological and biochemical characteristics.

B. coagulans is a Gram-positive, spore-forming, motile rod (0.9μm by 3.0μm to 5.0μm in size), aerobic to microaerophilic and as all other species in genus Bacillus, forms endospores, which are resistant to chemical and physical agents. It may appear Gram-negative when entering the stationary phase of growth. The temperature optimum for growth is 50 °C. IMVic Tests VP and MR (methyl-red) tests are positive. Citrate and Nitrate tests are negative.

Bacillus coagulans has been approved for veterinary purposes as GRAS by the FDA's Center for Veterinary Medicine, as well as by the EU and is listed by AAFCO for use as a direct fed microbial in livestock production. Its main use is thus is veterinary applications, especially as a probiotic in pigs and shrimp. There are some references to use of this bacterium in humans, especially in improving the vaginal flora. On activation of spore formation in the acidic environment of the stomach, this organism can germinate and proliferate in the intestine.

Bacillus coagulans is often marketed as Lactobacillus sporogenes or a 'sporeforming lactic acid bacterium' probiotic , but this is an outdated name due to taxonomic changes in 1939. Although Bacillus coagulans does produce L+ lactic acid, the bacterium used in these products is not a lactic acid bacterium, as Bacillus species do not belong to the lactic acid bacteria. By definition, lactic acid bacteria (Lactobacillus, Bifidobacterium) do not form spores. Therefore, using the name 'Lactobacillus sporogenes' is scientifically incorrect.