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

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 0.25x MRS plus 1% corn steep liquor or 0.5x 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.