6533b825fe1ef96bd128288f

RESEARCH PRODUCT

Anaerobic Reduction of Glycerol to Propanediol-1.3 by Lactobacillus brevis and Lactobacillus buchneri

subject

description

Summary Three strains of Lactobacillus brevis and one strain of Lactobacillus buchneri grew very poorly on glucose. Good growth was observed on glucose plus glycerol; while glucose was fermented to acetate or ethanol, lactate and CO 2 , glycerol was dehydrated to 3-hydroxypropanal and subsequently reduced to propanediol-1.3. Cell extracts of L. brevis and L. buchneri grown on glucose plus glycerol contained a B 12 -dependent glycerol dehydratase and a propanediol-1.3 dehydrogenase. Glycerol was not metabolized when used as the only substrate. Fructose as sole carbon source was partially reduced to mannitol. The joint fermentation of fructose and glycerol yielded propanediol-1.3 from glycerol. Ribose was fermented but did not support glycerol fermentation. Extracts from ribose grown cells did not contain glycerol dehydratase or propanediol-1.3 dehydrogenase. Besides glycerol the following diols were metabolized as cosubstrates with glucose: propanediol-1.2, ethylene glycol and butanediol-2.3 yielding propanol-1, ethanol and butanol-2 respectively. Washed cells of two L. brevis strains, B 18 and B 20, formed propanediol-1.3 and propanediol-1.2 from glycerol, the third strain B 22 formed only propanediol-1.2 from glycerol in the absence of glucose.