BIOCATALYST FOR PRODUCING D-LACTIC ACID

摘要

It is intended to provide a process for highly producing D-lactic acid. It is also intended to provide a process for highly selectively producing D-lactic acid having a high optical purity with the formation of little organic acids as by-products. D-Lactic acid is produced by culturing a microorganism having inactivated or lowered pyruvate formate-lyase activity and elevated Escherichia coli-origin NADH-dependent D-lactic acid dehydrogenase (ldhA) activity, a microorganism having inactivated or lowered FAD-dependent D-lactic acid dehydrogenase activity, or a microorganism as described above having a TCA cycle, inactivated or lowered malic acid dehydrogenase activity and inactivated or lowered aspartic acid ammonia-lyase activity. The ldhA activity is elevated by ligating a gene encoding ldhA to a promoter of a gene controlling the expression of a protein, which participates in a glycolysis system, a nucleic acid biosynthesis system or an amino acid biosynthesis system, on genome.