METABOLISM OF RHAMNOSE AND OTHER SUGARS BY STRAINS OF CLOSTRIDIUM-ACETOBUTYLICUM AND OTHER CLOSTRIDIUM SPECIES

Twenty-two strains of Clostridium species, including 7 each of Clostridium acetobutylicum and C. butylicum, grew well when supplied with common hexose and pentose carbohydrates as sole carbon sources. Glucosamine and galacturonic acid were used by most strains, but glucuronic acid supported the growth of relatively few. Rhamnose was used, to various degrees, by all strains tested, but less acid was produced than observed from other carbohydrates. The major fermentation products from rhamnose included acetic acid, propionic acid, butyric acid, n-propanol, and 1,2-propanediol. Fermentation product concentration in batch culture was enhanced by inclusion of bicarbonate in the medium. With either arabinose or pyruvate as the source of carbohydrate, supplementation of the medium with 1,2-propanediol resulted in its conversion to propionic acid and n-propanol. With glucose as the carbohydrate source the conversion of 1,2-propanediol to propionic acid and propanol was repressed.