The asymmetric reduction of ethyl-2-oxo-4-phenylbutyrate (EOPB) catalyzed by saccharomyces cerevisiae in organic phase to synthesize chiral ethyl-2-hydroxy-4-phenylbutyrate (EHPB) was investigated. In diethyl ether with the initial EOPB concentration of 6 mmol·L-1 , the e. e.(R)-EHPB was increased 19％ by using wet baker's yeast (WB) as biocatalyst compared to that by dry baker's yeast (DB). However, the catalytic activity and stability of WB was lower than that of DB. The enantioselectivity of the reduction to produce (R) -EHPB was reduced with the increase of the log P value (0.82-3.2 ) of employed organic solvents. Although dimethylbenzene and cyclohexane had the same log p value (3.2), the enantioselectivity of the reduction was reversed from R to S when dimethylbenzene was in place of cyclohexane as reaction media. Significant changes were observed in the UV absorption and fluorescence spectrum of the YADH from the yeast pretreated by the solvents. These facts indicated that the synergistic effect of solvent polarity and its spatial structure led to the change of the catalytic behavior of baker's yeast%研究了非水介质中面包酵母催化不对称还原2-氧代-4-苯基丁酸乙酯(EOPB)合成手性2-羟基-4-苯36基丁酸乙酯(EHPB)的反应.乙醚体系中湿酵母(WB)催化6mmol·L-1EOPB合成(R)-EHPB的e.e.值较之于干酵母(DB)提高了近19%,但WB稳定性较差.DB催化该反应的立体选择性随溶剂logP(0.82-3.2)的增加而降低,反应从相同logP值(3.2)的二甲苯转换至环己烷后产物构型由R转为S,经有机溶剂预处理后酵母醇脱氢酶(YADH)的紫外及荧光光谱的特征变化表明溶剂分子极性与结构的协同作用下酵母催化行为发生了改变.
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