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Appl Microbiol Biotechnol. 2004 Dec;66(2):160-5. Epub 2004 Jul 29.

Production of L-lactic acid from a mixture of xylose and glucose by co-cultivation of lactic acid bacteria.

Author information

1
Faculty of Engineering, Department of Materials Science and Technology, Niigata University, Ikarashi 2, Niigata, 950-2181, Japan. mtanig@eng.niigata-u.ac.jp

Abstract

The production of optically pure lactic acid in a high yield from xylose or a mixture of xylose and glucose, which is a model hydrolysate of lignocellulose, is described. In a single cultivation, Enterococcus casseliflavus produced 38 g/l of lactic acid with an optical purity of 96% enantiomeric excess (ee) and 6.4 g/l of acetic acid from 50 g/l of xylose when MRS medium was used. When a mixture of 50 g/l of xylose and 100 g/l of glucose was used as the carbon source in a cultivation of E. casseliflavus alone, glucose was converted to lactic acid in the early phase of the cultivation but xylose was hardly consumed. In a co-cultivation where E. casseliflavus and Lactobacillus casei specific for glucose were simultaneously inoculated, little or no lactic acid was produced after the glucose was almost consumed. A co-cultivation with two-stage inoculation (in which E. casseliflavus was added at a cultivation time of 40 h after L. casei cells were inoculated) resulted in complete consumption of 50 g/l of xylose and 100 g/l of glucose. In the co-cultivation, 95 g/l of lactic acid with a high optical purity of 96% ee was obtained at 192 h. Such a co-cultivation using two microorganisms specific for each sugar is considered to be one promising cultivation technique for the efficient production of lactic acid from a sugar mixture derived from lignocellulose.

PMID:
15558273
DOI:
10.1007/s00253-004-1671-x
[Indexed for MEDLINE]

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