（S）-（-）-β-羟基苯丙酸乙酯的微生物法合成

采用酿酒酵母CGMCC No．2266菌体，不对称还原β-羰基苯丙酸乙酯制备光学纯（S）-（-）-β-羟基苯丙酸乙酯。结果表明：采用初始pH为8．0的液体发酵培养基培养的CGMCCNo．2266菌体经过50℃预热处理30min后用于生物转化获得的（S）-（-）-G-羟基苯丙酸乙酯对映体过剩值可以达到100％ee。确定了合成（S）-（-）-β-羟基苯丙酸乙酯的较佳转化条件为pH7．0，温度30℃，转化时间24h，底物浓度为3．63mmol／L，菌体用量为86g/L（干重／反应体积）。以10％葡萄糖为辅助底物，产率比不加辅助底物时提高了75．4％。在最佳转化条件下反应转化率及（S）-（-）-β-羟基苯丙酸乙酯对映体过剩值可分别达到98．4％和100％ee。

Synthesis of (S)-(-)-Beta-hydroxy-benzenepropanoic acid ethyl ester by microorganism transformation

Beta-hydroxy-benzenepropanoic acid ethyl ester (HPPE) is an important precursor for the synthesis of chiral pharmaceuticals.The carbonyl asymmetric reduction of β-carbonyl phenylpropionate to (S)-(-)-Beta-hydroxy-benzenepropanoic acid ethyl ester by CGMCC No.2266 was investigated.The enantiometric excess of (S)-(-)-Beta-hydroxy-benzenepropanoic acid ethyl ester could achieve 100%ee by reduction of CGMCC No.2266 cultivated by the liquid medium of intial pH 8.0 and preheated at 50 ℃ for 30 min.The effects of bioconversion conditions on both yield and enantiomeric excess were evaluated.The reaction conditions for the reduction of β-carbonyl phenylpropionate to (S)-(-)-Beta-hydroxy-benzenepropanoic acid ethyl ester were optimized,and the highest yield was achieved when the bioconversion was taken place at pH 7.0 and 30 ℃ for 24 h.The substrate concentration was 3.63 mmol/L and the biomass was 86 g/L(w/v).The experimental data showed that the best co-substrate was glucose and the optimal glucose concentration was 10%.The yield and (S)-(-)-Beta-hydroxy-benzenepropanoic acid ethyl ester enantiometric excess achieved as high as 98.4% and 100%ee,respectively.