醇类物质诱导培养改善近平滑假丝酵母(Candida parapsilosis)去消旋转化能力

Improving Enantioselectivity of Candida parapsilosis for Deracemization of (R,S)-1-phenyl-1,2-ethanediol by Addition of Alcohols during Cell Cultivation

采用近平滑假丝酵母Candidaparapsilosis全细胞去消旋转化外消旋苯基乙二醇(PED)制备S-苯基乙二醇.主要研究了在菌体培养阶段添加底物醇类和酮类对菌体生长及菌体产酶的影响.研究发现添加乙醇可以促进细胞生长,提高细胞中脱氢酶活力,从而改善菌体立体选择性转化能力.通过在菌体培养至对数生长期时添加0.1%乙醇,菌体量增长10%,相对酶活提高30%,采用相同浓度菌体转化105mmol/L(R,S)-苯基乙二醇时,产物(S)-苯基乙二醇的对映过量值从90%提高至99%,产率从87.3%提高至92.4%.

（R,S）-1-phenyl-1,2-ethanediol （PED） was deracemized to the corresponding （S）-enantiomer by using whole cells of the Candida parapsilosis as a biocatalytic system. To improve enantioselectivity of Candida parapsilosis, a new method was developed by the addition of alcohols or ketones during cell cultivation. The results showed that there were little effect caused by addition of diols, middle-chain alcohols and ketones, but there were increases in cell mass, enantiomeric excess and yield by addition of short-chain （C1-C4） alcohols such as ethanol （EtOH） especially. Effects of the phase and concentration of added ethanol during cell cultivation on enantioselectivity of the cells were also investigated. When cultivation continued for 16 h under the condition of 0.1% （φ） ethanol, the cell mass increased by 10% and the relative enzyme activity increased by 30%. Meanwhile, the conversion of 105 mmol/L R,S-PED to S-PED with the cells cultured under this condition, an improvement of enantiomeric excess from 91% to 99% and a yield up to 92% were achieved.