Abstract: Microbial cells and/or a preparation thereof of a microorganism is allowed to act on ester of .gamma.-halogenated-acetoacetic acid, and its carbonyl group at .beta.-position is stereospecifically reduced to produce ester of (S)-.gamma.-halogenated-.beta.-hydroxybutyric acid in a short period of time at a highly accumulated degree and at a high yield, the microorganism being selected from the group consisting of those belonging to the genera Phoma, Nectria, Pseudonectria, Spondylocladium, Melanospora, Metarhizium, Gliocladium, Pestalotia, Pestalotiopsis, Curvularia, Hormonema, Sydowia, Sarcinomyces, Dothiora, Xanthothecium, Dothidea, Pringsheimia, and Selenophoma.

Abstract: A method for producing a 3-hydroxy nitrogen-containing six-membered cyclic compound is provided. Namely, microbial cells of a microorganism and/or a preparation obtained from the microbial cells is allowed to act on a nicotinic acid derivative or a 2-pyrazinecarboxylic acid derivative represented by the following general formula: ##STR1## wherein R.sub.1 and R.sub.2 may be the same or different, representing hydrogen atom, halogen atom, hydroxyl group, amino group, carboxyl group, cyano group, oxime group, or alkyl group having a number of carbon atom or atoms of 1 to 5 respectively, and A represents carbon atom or nitrogen atom, the microbial cells and/or the preparation obtained from the microbial cells having an ability to perform hydroxylation of the nicotinic acid derivative or the 2-pyrazinecarboxylic acid derivative accompanied by decarboxylation of carboxyl group.

Abstract: Microbial cells and/or a preparation therefrom of a microorganism is allowed to act on an ester of .gamma.-substituted-acetoacetic acid, and a carbonyl group at its .beta.-position is stereospecifically reduced, wherein 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, preferably, the microorganism is microorganism belonging to the genus Aureobasidium. Thus an optically active ester of .gamma.-substituted-.beta.-hydroxybutyric acid having a high optical purity is produced in a short period of time at a high accumulated concentration and a high yield.