酵母发酵液催化不对称还原反应合成(s).docVIP

酵母发酵液催化不对称还原反应合成(S) 【关键词】 酵母发酵液；不对称还原反应；4 　　Optimization for the asymmetric synthesis of (S)ethyl 4chloro3hydroxybutanoate directly catalyzed by yeast fermentation broth 　　【Abstract】 AIM: To optimize the asymmetric reduction of ethyl 4chloro3oxobutanoate (COBE) to (S)ethyl 4chloro3hydroxybutanoate ［(S)CHBE］ directly catalyzed by yeast (Saccharomyces cerevisiae) fermentation broth. METHODS: The variation of COBE, (S)CHBE and reductive sugar in reaction course and the influence of some reaction conditions (substrate, energy source) on asymmetric synthesis of (S)CHBE directly catalyzed by yeast fermentation broth were examined respectively, and the optimal conditions of asymmetric synthesis of (S)CHBE were optimized by orthogonal test design. RESULTS：The consumption of substrate and formation of product were mostly in the initial reaction course as well as consumption of reductive sugar. Repeated feeding strategy of substrate and energy source was favored for the formation of (S)CHBE. The optimum reaction conditions were sucrose repeated feeding strategy Ⅱ (feeding 5 g/120 mL after 2 h of reaction), substrate feeding strategy Ⅳ［0.5(3)］, buffer concentration 2 g/120 mL, βcyclodextrin concentration 2 g/120 mL. CONCLUSION: Optically active (S)CHBE is synthesized by yeast fermentation broth with 96% yield and 100% ee (enantiometric excess) under the optimum reaction conditions. 　　【Keywords】 yeast fermentation broth; asymmetric reduction; ethyl 4chloro3oxobutanoate; (S)ethyl 4Chloro3hydroxybutanoate; orthogonal text 　　【摘要】 目的：优化酵母发酵液直接催化4氯乙酰乙酸乙酯(COBE)合成(S)4氯3羟基丁酸乙酯((S)CHBE)的反应条件. 方法：考察酵母发酵液催化该反应过程中基质变化的规律，研究底物和能源供体对反应的影响，并通过正交实验设计法优化反应条件. 结果：在酵母发酵液催化COBE不对称还原反应的过程中，底物和还原糖消耗、产物合成相对集中在反应的前期；反复分批式添加底物和蔗糖有利于反应效率的提高；正交实验优化反应条件的结果表明：酵母发酵液直接催化COBE不对称还原反应合成(S)CHBE的最佳反应条件为：蔗糖添加方式Ⅱ（反应开始2 h后添加5 g/120 mL），底物添加方式Ⅳ［0.5(3)］，缓冲剂添加量2 g/120 mL，β环糊精添加量为2 g/120 mL，反应后测定产物的产率达96%，ee(对映体过量值)达100%. 结论：通过反应条件优化提高了酵母发酵液的催化效果. 　　【关键词】 酵母发酵液；不对称还原反应；4氯乙酰乙