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水相中酵母细胞催化4-氯乙酰乙酸乙酯不对称还原反应
引用本文:杨忠华,姚善泾.水相中酵母细胞催化4-氯乙酰乙酸乙酯不对称还原反应[J].催化学报,2004,25(6):434-438.
作者姓名:杨忠华  姚善泾
作者单位:浙江大学化学工程与生物工程学系,浙江杭州
基金项目:国家自然科学基金资助项目 ( 2 0 2 760 65 )
摘    要: 利用活性酵母细胞催化4-氯乙酰乙酸乙酯(COBE)的不对称还原可以直接合成具有光学活性的4-氯-3-羟基丁酸乙酯(CHBE). 实验发现,在水相体系中主要生成D-(S)-型产物,COBE的转化率及CHBE的收率和光学选择性都比较高. 考察了底物和产物的浓度、辅助底物的种类和浓度、体系的pH和温度以及菌体培养条件等因素对反应的影响. 结果表明,在较低COBE浓度下R型产物占优,在高浓度下主要是S型产物; 较高的反应温度有利于S型产物的生成,pH≈8.0时可获得较高的S型产物选择性; 产物CHBE对COBE的还原反应具有一定的抑制作用. 在酵母催化COBE还原的同时需要一定的辅助底物来再生辅酶NAD(P)H,利用乙醇、异丙醇和仲丁醇作辅助底物可获得较高的立体选择性. 对数生长期和厌氧条件培养的细胞对生成S型产物较有利.

关 键 词:酵母  4-氯乙酰乙酸乙酯  水相  不对称还原  手性化合物  4-氯-3-羟基丁酸乙酯
文章编号:0253-9837(2004)06-0434-05
收稿时间:2004-06-25

Asymmetric Reduction of Ethyl 4-Chloro-3-Oxobutanoate to Ethyl 4-Chloro-3-Hydroxybutanoate by Yeast Cells in Aqueous Phase
YANG Zhonghua,YAO Shanjing.Asymmetric Reduction of Ethyl 4-Chloro-3-Oxobutanoate to Ethyl 4-Chloro-3-Hydroxybutanoate by Yeast Cells in Aqueous Phase[J].Chinese Journal of Catalysis,2004,25(6):434-438.
Authors:YANG Zhonghua  YAO Shanjing
Institution:YANG Zhonghua,YAO Shanjing *
Abstract:The asymmetric reduction of ethyl 4-chloro-3-oxobutanoate (COBE) to optically active ethyl 4-chloro-3-hydroxybutanoate (CHBE) catalyzed by yeast cells in aqueous phase was investigated. The reduction was conducted in Tris-HCl buffer, and the concentrations of COBE and CHBE and the optical purity of product were determined by capillary GC and HPLC equipped with a chiralcel OB column, respectively. The product was mainly D-(S)-CHBE. Both the yield and the stereo-selectivity of CHBE were higher for the reaction. However, the product was mainly R-CHBE when the initial concentration of COBE was low, and the product was mainly S-CHBE when the initial concentration of COBE was higher. The CHBE had a few of inhibition effects on the reaction. In the COBE reduction, a co-substrate was required to regenerate the NAD(P)H. Ethanol, isopropanol and secondary butyl alcohol as the co-substrate were advantageous to the stereo-selectivity of S-CHBE, but glucose as the co-substrate could achieve higher yield. The higher temperature and pH 8 0 were favorable to the production of S-CHBE. The cells in logarithmic growth phase and cultured under anaerobic condition were also favorable to the stereo-selectivity of S-CHBE. 92% for yield and 90% for ee of S-CHBE were obtained respectively under appropriate reaction conditions.
Keywords:yeast  ethyl 4-chloro-3-oxobutanoate  aqueous phase  asymmetric reduction  chiral compound    ethyl 4-chloro-3-hydroxybutanoate
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