Why Sequence Bacillus coagulans?

Bacilus coagulans strain 36D1 and its close relatives are ideal biocatalysts for fermentation of lignocellulosic biomass to fuels and chemicals. This bacterium is an acidophile and a moderate thermophile (grows at pH 5.0 and at 55°C). These characteristics are similar to the optimal conditions for the activity of fungal cellulases, which have been developed with significant support from DOE for simultaneous saccharification and fermentation (SSF) of cellulose to useful products (fuel ethanol, lactic acid, etc.). The optimal growth conditions for the biocatalysts currently used by industry for production of ethanol or lactic acid significantly differ from the optimal conditions for cellulase activity. This mismatch leads to higher usage of expensive cellulases than is necessary. Bacillus coagulans strains isolated by JGI's collaborators are unique in matching the requirements for cellulase activity while requiring significantly less cellulase. Knowing the genome sequence will provide important insight into the metabolic capability of these second-generation biocatalysts and will substantially aid in metabolic engineering of these biocatalysts for production of fuel ethanol or other products of choice.

From a physiological standpoint, Bacillus coagulans and other sporogenic lactic acid bacteria straddle the phylogenetic distance between other Bacillus species and lactic acid bacteria such as Lactobacillus and Lactococcus. Several Bacillus species and lactic acid bacteria have been sequenced, but no member of this unique, widely distributed group of sporogenic lactic acid bacteria has been. These bacteria are metabolically versatile, grow in mineral salts, utilize a wide range of carbon compounds as carbon and energy source, and ferment these compounds to optically pure lactic acid. B. coagulans has been reported as responsible for spoilage of milk products. It is a source of thermostable enzymes as well as the antimicrobial peptide coagulin and is also used as a dietary additive for piglets and chickens. The genome sequence information will be of great value to bacterial physiologists in understanding this intriguing organism's metabolic diversity and evolution.

CSP project participants: K. T. Shanmugam (proposer) and L. O. Ingram (Univ. of Florida).