Conversion of biomass hydrolysates and other substrates to ethanol and other chemicals by Lactobacillus buchneri

Abstract

Aims: A Lactobacillus buchneri strain NRRL B-30929 can convert xylose and glucose into ethanol and chemicals. The aims of the study were to survey three strains (NRRL B-30929, NRRL 1837 and DSM 5987) for fermenting 17 single substrates and to exam NRRL B-30929 for fermenting mixed substrates from biomass hydrolysates. Methods and Results: Mixed acid fermentation was observed for all three L. buchneri strains using various carbohydrates; the only exception was uridine which yielded lactate, acetate and uracil. Only B-30929 is capable of utilizing cellobiose, a desired trait in a potential biocatalyst for biomass conversion. Flask fermentation indicated that the B-30929 strain can use all the sugars released from pretreated hydrolysates, and producing 1·98-2·35 g l-1 ethanol from corn stover hydrolysates and 2·92-3·01 g l-1 ethanol from wheat straw hydrolysates when supplemented with either 0·25× MRS plus 1% corn steep liquor or 0·5× MRS. Conclusions: The L. buchneri NRRL B-30929 can utilize mixed sugars in corn stover and wheat straw hydrolysates for ethanol and other chemical production. Significance and Impact of the Study: These results are valuable for future research in engineering L. buchneri NRRL B-30929 for fermentative production of ethanol and chemicals from biomass. © 2009 The Society for Applied Microbiology.