Production of(S)-CHBE by asymmetric reduction with whole cells of Candida magnoliae as catalyst

Optically active ethyl(S)-4-chloro-3-hydrobutanoate((S)-CHBE),a useful chiral synthon,was prepared by stereoselective bioreduction of ethyl 4chloro-3-oxobutanoate(COBE) with Candida magnoliae cells.Effects of culture condition,co-substrates and their concentrations,reaction time,temperature,pH,substrate concentration,and cell concentration on the yield and enantiomeric excess(e.e.) of product were examined in detail.The results showed that 99.2% of 12.1 g/L COBE was reduced to(S)-CHBE with an e.e.value of 85.2% by 9 g/L cells of Candida magnoliae at 30 ℃ in phosphate buffer of pH 6.0 added with 10 g/L of glucose.