全细胞近平滑假丝酵母(Candida parapsilosis)SYB-1不对称转化苯基乙二醇

Asymmetric Conversion of 1-Phenyl-1,2-ethanediol by Candida parapsilosis SYB-1

为了获得较高光学纯度和产率的光学纯苯基乙二醇,通过筛选得到不对称转化外消旋苯基乙二醇效果较好的菌株近平滑假丝酵母(Candida parapsilosis)SYB-1,其转化产物为S-苯基乙二醇,光学纯度为91% e.e.,产率为88%;通过对近平滑假丝酵母SYB-1拆分苯基乙二醇的反应条件进行优化研究,在细胞量5%、底物浓度8‰、pH值6.5、温度33oC、反应48 h条件下,产物光学纯度可以提高至e.e. 99%. 在证明中间体为b-羟基苯乙酮后推测全细胞近平滑假丝酵母SYB-1拆分外消旋苯基乙二醇的机理是通过将R-苯基乙二醇氧化为中间体后不对称还原为S-苯基乙二醇.

Optically active 1-phenyl-1,2-ethanediol is an extremely valuable and versatile alcohol used as a chiral building block in organic synthesis. Among the microorganisms which are able to produce S-1-phenyl-1,2-ethanediol from the racemate by asymmetric conversion, Candida parapsilosis SYB-1 was selected as an candidate biocatalyst for the preparation of S-1-phenyl-1,2-ethanediol with the optical purity of 91% e.e. and the yield of 88%. It is found that the optimal conditions for biocatalytic conversion were 5% cells, 8?R,S-1-phenyl-1,2-ethanediol, pH 6.5, temperature 33oC and reaction time 48 h. Under such conditions, the optical purity of S-1-phenyl-1,2-ethanediol was improved from 91% e.e. to 99% e.e. By detecting the intermediate produced in the reaction by GC-MS, it was suggested that S-enantiomer was produced from the intermediate identified as b-hydroxyacetophenone by asymmetric reduction after stereoselective oxidation of R-enantiomer to b-hydroxyacetophenone.