(S)-4-Halo-3-acetoacetic acid esters are important as HMG-CoA reductase inhibitors and intermediates for synthesizing various medicines and agricultural chemicals such as D-carnitine. The known methods for producing optically active 4-halo-3-hydroxybutyric acid esters include the asymmetric reduction methods using 3.alpha.-hydroxysteroid dehydrogenase (Japanese Patent Laid-Open Publication (JP-A) No. Hei 1-1277494) or bakers' yeast (J. Am. Chem. Soc. 105, 5925-5926 (1983), and JP-A-Sho 61-146191).
Furthermore, the known methods for reducing 4-haloacetoacetic acid esters to produce 4-halo-3-hydroxybutyric acid esters include methods using enzymes such as Saccharomyces cerevisiae-derived D-enzyme-1 and D-enzyme-2 (J. Org. Chem. 56, 4778-4783 (1991)), L-enzyme-1 and L-enzyme-2 (Biosci. Biotech. Biochem. 58, 2236-2240 (1994)), aldehyde reductase derived from Sporobolomyces salmonicolor (Biochim. Biophys. Acta 1122, 57-62 (1992)), aldehyde reductase derived from Sporobolomyces sp. (Biosci. Biotech. Biochem. 57, 303-307 (1993)), aldehyde reductase derived from Candida alcabins (Biosci. Biotech. Biochem. 57, 303-307 (1993)), aldehyde reductase derived from Trichosporon fermentans (JP-A-Hei08-126487 (960521)), aldehyde reductase derived from Hansenula mrakii (JP-A-Hei08-126486 (960521)), ethyl ketopantothenate reductase derived from Candida macedoniensis (Arch. Biochem. Biophys. 294, 469-474 (1992)), and ethyl 4-chloroacetoacetate reductase derived from Geotrichum candidum (Enzyme Microb. Technol. 14, 731-738 (1992)). Among these methods, those using ethyl ketopantothenate reductase derived from Candida macedoniensis, D-enzyme-1 and D-enzyme-2 derived from Saccharomyces cerevisiae, and ethyl 4-chloroacetoacetate reductase derived from Geotrichum candidum produce the (S)-enatiomer of 4-halo-3-hydroxybutyric acid esters. However, these methods for producing (S)-4-halo-3-hydroxybutyric acid esters have the disadvantages of low optical purity and product yield.
The present inventors found that microorganisms including the genus Kluyveromyces reduce 4-haloacetoacetic acid esters to produce optically active 4-halo-3-hydroxybutyric acid esters and filed a patent application on the finding (JP-A-Hei 6-209782). However, the mechanism of the action of these microorganisms has not been clarified. Furthermore, this method enables producing highly optically pure (S)-4-halo-3-hydroxybutyric acid esters, but its product yield is unsatisfactory. When we tried to increase product yield, optical purity was lowered.