羰基还原酶产生菌Candida ontarioensis制备(R)-2-氯-1-(3-氯苯基)乙醇

从实验室保藏的菌株中筛选获得Candida sp.PT2A,并通过18S rRNA鉴定为安大略假单胞菌Candida on-tarioensis。对C.ontarioensis不对称还原合成(R)-2-氯-1-(3-氯苯基)乙醇的发酵产酶条件和转化条件进行优化,确定了最适的发酵产酶条件和转化条件:温度30℃,初始pH 6.5,摇床转速180 r/min,菌体质量浓度200 g/L。采用2-氯-1-(3-氯苯基)乙酮质量浓度为10 g/L时,还原反应72 h,(R)-2-氯-1-(3-氯苯基)乙醇的e.e.值为99.9%,产率为99%;底物质量浓度提高至30 g/L时,产率下降为84.3%。采用十六烷基三甲基溴化铵(CTAB)对C.ontarioensis细胞进行通透性处理(CTAB g/L,4℃下处理20 min),在30 g/L底物下反应24 h,产物的e.e.和产率分别达到99.9%和97.5%。

Asymmetric synthesis of (R)-2-chloro-1-(3-chlorophenyl) ethanol by carbonyl reductase-producing strain Candida ontarioensis

A carbonyl reductase-producing strain Candida sp.PT2A was selected from strain collection of our laboratory and was identified as Candida ontarioensis by 18S rRNA sequencing.The fermentation conditions and bioreduction conditions for the asymmetric synthesis of(R)-2-chloro-1-(3-chlorophenyl)ethanol by Candida ontarioensis were optimized as temperature of 30 ℃,initial pH of 6.5,rotation speed of 180 r/min,and cell concentration of 200 g/L.After for 72 h reaction,the e.e.and the product yield were 99.5% and 99%,respectively on substrate concentration of 10 g/L,whereas the yield was dropped to 84.3% on enhanced substrate concentration of 30 g/L.Using C.ontarioensis whole cells pretreated with 4 g/L CTAB for 20 min at 4 ℃,the product e.e.and the yield reached 99.9% and 97.5% on substrate concentration of 30 g/L at shortened reaction time of 24 h.