ANAEROBIC REDUCTION OF GLYCEROL TO PROPANEDIOL-1.3 BY LACTOBACILLUS-BREVIS AND LACTOBACILLUS-BUCHNERI

Three strains of L. brevis and 1 strain of L. buchneri grew very poorly on glucose. Good growth was observed on glucose plus glycerol; while glucose was fermented to acetate or ethanol, lactate and CO2, glycerol was dehydrated to 3-hydroxypropanal and subsequently reduced to 1,3-propanediol. Cell extracts of L. brevis and L. buchneri grown on glucose plus glycerol contained a B12-dependent glycerol dehydratase and a 1,3-propanediol dehydrogenase. Glycerol was not metabolized when used as the only substrate. Fructose as sole C source was partially reduced to mannitol. The joint fermentation of fructose and glycerol yielded 1,3-propanediol from glycerol. Ribose was fermented but did not support glycerol fermentation. Extracts from ribose grown cells did not contain glycerol dehydratase or 1,3-propanediol dehydrogenase. Besides glycerol the following diols were metabolized as cosubstrates with glucose: 1,2-propanediol, ethylene glycol and 2,3-butanediol yielding 1-propanol, ethanol and 2-butanol, respectively. Washed cells of 2 L. brevis strains B 18 and B 20 formed 1,3-propanediol and 1,2-propanediol from glycerol; the third strain, B 22, formed only 1,2-propanediol from glycerol in the absence of glucose.