Microbial Production of Optically Active 1,3-Butanediol from 4-Hydroxy-2-butanone.

synthesizing various optically active compounds such as azetidinone derivatives, which are intermediate materials for penem and carbapenern antibfotics,i'2) pheromones,3) fragrances,4'S} and insecticides.6) Although microbial asymmetric processes for optically aetive 1,3-BDO have been reported,T'S) the product{vity was not satisfactory, and they produced only (R)-(-)-1,3-BDO. Thus, we started a program to establish an econemical and convenient microbial process fOr the preduction of both (R)-(-) and (S)-(+)-1,3-BDO with high optical purity from 4-hydrexy-2-butanone {4H2B). Allmicroorganismsusedweretypeculturespreservedinourlaberatories, For screening, each strain was cultivated in 1OOml of nutrient media (fbr yeasts, Candido, Hitnsenuia, Kluyveromyces, etc., YM medium containing 2,O%glucose,O.5%Polypepton,O.3%yeastextruct,andO.3%maltextract, pH 6.0; for bacteria, Escherichia, B cillus, etc., YPM mediurn containing 2.0et6 glucose, O.3% Pelypepton, O.5% yeast extract, O.3% meat extract, O.2% (NH.),SO., and O.1% KH,PO,, pH 7.0) in a 500-ml Sakaguchi fiask with reciprecal shaking at 300C for 48h. Lactic acid bacteria, Lactobacillus, Leueonostoek, Streptococeus, etc., were cultivated in 100ml of YPM medium with t% CaC03 in a 500-rnl Er]enrneyer fiask under [otary shaking at 300C for 4g h. The cells in 50 ml ofbroth were harvested by centrifugation, washed ence with pltysiological saline, and resuspended in S ml of IOO mM potassium phosphate bufibr (pH 7.0). After addition of O,6g of glucose to the suspension in test tubes, it was incubated at 300C for 1Omin, then 50mg of4H2B was added and the reaction mixture was incubated at 300C for 48 h on a test tube shaker (230 oscillation/min). Gas chromatography was to assay 1,3-BDO and 4H2B under the fo11owing conditions: the column; Thermon 3000 (5%, 2m, Chremosorb, Shinwa Kako), the celumn temperature; 1200C, the detecter; FID, the carrier gas; He at SO mllmin. The optical purity ef r,3-BDO was calculated by the enantiomeric excess (% e.e.) of 1,3-BDO diacetate as fo11ows. After removal of cel]s with centrifugation, 2ml of supernatant was saturated