摘要
从5株酵母菌中优选出可用于乙酰乙酸乙酯（EAA）不对称还原为（R）-3-羟基丁酸乙酯的高转化活力菌株膜醭毕赤酵母-218，以其为出发菌株经紫外诱变处理，并结合底物抗性筛选，获得较佳菌株PC-126，该菌株相对酶活力和e．e．值（对映体过量值）分别比出发菌株提高39％和11％。由该突变株的底物耐受性研究表明，底物浓度可提高至0．35mol／L。同时考察了PC-126菌株在5L发酵罐中的产酶过程和转化时间曲线，结果表明，最佳菌体培养时间为14～16h，酶活力可达111．7U／L，不对称还原反应转化时间为16h，产率可达70．8％，e．e．值可达80．5％。
Pichia membranaefaciens Hansen 218 with high enzyme activity for asymmetric reduction of ethyl acetoacetate （EAA） to （R）-ethyl - 3 - hydroxybuty was screened out from five yeast strains. Strain PC- 126 was obtained by UV treatment and the substrate resistant screening method. The relative enzyme activity and the enantiomeric excess were improved by 39% and 11 % respectively, compared with the original strain. It was found that the initial EAA concentration could be increased to 0.35 mol/L for asymmetric reduction. The time curves for enzyme-producing and asymmetric reduction in 5 L fermenter was also investigated. The results showed that the optimized cultivation time for PC- 126 was 14-16 h, with the enzyme activity reached to 111.7 U/L, and the suitable asymmetric reduction time 16 h, with the yield and e.e. 70. 8% and 80. 5%, respectively.
出处
《药物生物技术》
CAS
CSCD
2009年第1期55-59,共5页
Pharmaceutical Biotechnology
基金
浙江省科技厅重大项目资助(2005C13034)
