Method for producing optically active ester of .gamma.-substituted-.beta.-hydroxybutyric acid

A method for producing an optically active ester of .gamma.-substituted-.beta.-hydroxybutyric acid, comprising the steps of:

• allowing microbial cells and/or a preparation therefrom of a microorganism to act on an ester of .gamma.-substituted-acetoacetic acid represented by a general formula (1);
• ##STR3## wherein X represents a halogen atom, a cyano group, or a protected or unprotected aminomethyl group, and R represents a lower alkyl group in the general formula (1);
• wherein the microorganism has an ability to stereospecifically reduce a carbonyl group at a .beta.-position of the ester of .beta.-substituted-acetoacetic acid represented by the general formula (1), and the microorganism is selected from the group consisting of those belonging to the genera Yarrowia, Filobasidium, Metschnikowia, Galactomyces, Ambrosiozyma, Trichosporonoides, Aureobasidium, Phaeococcomyces, Rosulomyces, Dothichiza, Emericellopsis, Calonectria, Colletotrichum, and Ceratocystis;
• and
• stereospecifically reducing the carbonyl group at the .beta.-position to produce the optically active ester of .gamma.-substituted-.beta.-hydroxybutyric acid represented by a general formula (2);
• ##STR4## wherein X and R in the general formula (2) are synonymous with X and R in the general formula (1).