2-氧代-4-苯基丁酸乙酯还原酶产生菌筛选及产酶条件

研究了利用生物催化不对称还原的方法制备(R)-2-羟基-4-苯基丁酸乙酯(R)-HPBE]。以2-氧代-4-苯基丁酸乙酯(OPBE)为底物,通过对实验室保藏菌株进行筛选,得到一株产物立体选择性较高的菌株G2ndida krusei SW2026,并对其发酵产酶条件进行研究。其最适的发酵培养基组成为4.5%葡萄糖,3%蛋白胨,1.5%牛肉膏,0.05%Mn~(2+);适宜的产酶发酵条件为初始pH 6.0,温度28℃,摇床转速180 r/min,发酵周期48 h。将此条件下发酵培养的菌体用于OPBE的不对称还原反应,产物(R)-HPBE的对映体过量值(e.e.)可达97.33%,产率最高达到72.54%。

Screening of strains for asymmetric reduction of ethyl 2-oxo-4-phenylbutyrate and its cultural conditions

The microbial asymmetric reduction of ethyl 2-oxo-4-phenylbutyrate (OPBE) for the preparation of ethyl (R)-2-hydroxy-4-phenylbutyrate (R)-HPBE] was investigated in this study. Among 63 microorganisms tested, Candida krusei SW2026, for the first time, was proven to be a highly effective biocatalyst in this reduction process. The optimum fermentation medium comprised: 4.5 % glucose, 3 % peptone, 1.5 % beef extract, and 0.05 % Mn~(2+); and the optimum cultivation conditions were: initial pH of 6.0, temperature of 28 ℃, rotation speed of 180 r/min, and fermentation time of 48 h. Under the optimized conditions, the asymmetric reduction of OPBE led to (R)-HPBE with the enantiomeric excess (e.e.) and the yield of 97.33 % and 72.54 %, respectively.