| | | 酵母发酵液催化不对称还原反应合成(S)
| | 毕业论文【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】 目的毕业论文：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)的毕业论文反应条件. 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氯乙酰乙酸乙酯；(S)4氯3羟基丁酸乙酯；正交实验
0引言
近年来，通过生物催化剂［1-3］催化羰基化合物的不对称还原反应合成光学活性醇的相关研究备受关注. 其中，(S)CHBE是合成降血脂、降胆固醇、心血管药及抗生素等药物的光学活性中间体，市场需求很大. 有关利用酵母干细胞和基因工程菌催化COBE不对称还原反应合成(S)CHBE的报道多为基础性研究［4-5］. 我们在前期研究酵母发酵液直接催化COBE不对称还原反应合成(S)CHBE反应的基础上［6］，进一步考察反应过程中基质的变化规律和底物、能源供体及添加方式对反应的不同影响，优化反应条件，为建立成熟的生产操作工艺条件奠定技术基础.
|
| | |
| | | | <<<<<全文未完>>>>> 全文字数约$$$zishu$$$字 | |
| | |
| |
|
教育论文中心