He Junyao, Mao Xudong, Sun Zhihao, Zheng Pu, Ni Ye, Xu Yan
Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Southern Yangtze University, Wuxi, PR China.
Biotechnol J. 2007 Feb;2(2):260-5. doi: 10.1002/biot.200600106.
In this study, whole cells of Saccharomyces uvarum SW-58 were applied in an aqueous-organic solvent biphasic system for the asymmetric reduction of ethyl 4,4,4-trifluoroacetoacetate to ethyl (R)-4,4,4-trifluoro-3-hydroxybutanoate [(R)-2]. The results of reduction in different aqueous-organic solvent biphasic systems showed that dibutylphthalate provided the best compromise between the biocompatibility and the partition of substrate and product among the solvents tested. To optimize the reaction, several factors such as reaction pH, temperature, shaking speed, volume ratio of the aqueous phase to the organic phase and ratio of biomass/substrate were investigated. It was found that the change of these factors obviously influenced the conversion and initial reaction rate, and had a minor effect on the enatiomeric excess of the product. Under the optimal conditions, 85.0% of conversion and 85.2% of enatiomeric excess were achieved. The bioconversion in the biphasic system was more efficient compared with that in the monophasic aqueous system, and product concentration as high as 54.6 g/L was reached in the organic phase without addition of co-enzyme.
在本研究中，将葡萄汁有孢汉逊酵母SW-58的全细胞应用于水-有机溶剂双相体系中，用于将4,4,4-三氟乙酰乙酸乙酯不对称还原为(R)-4,4,4-三氟-3-羟基丁酸乙酯[(R)-2]。在不同水-有机溶剂双相体系中的还原结果表明，邻苯二甲酸二丁酯在所测试的溶剂中，在生物相容性以及底物和产物在溶剂间的分配方面达到了最佳平衡。为优化反应，研究了几个因素，如反应pH、温度、振荡速度、水相与有机相的体积比以及生物质/底物比。发现这些因素的变化明显影响转化率和初始反应速率，而对产物的对映体过量影响较小。在最佳条件下，转化率达到85.0%，对映体过量达到85.2%。与单相水体系相比，双相体系中的生物转化更高效，并且在不添加辅酶的情况下，有机相中产物浓度高达54.6 g/L。
