伴有辅酶再生过程的Saccharomyces cerevisiae B5不对称还原2’-氯-苯乙酮的催化反应动力学

Kinetic Model of Asymmetric Reduction of 2’-chloroacetophenone by Saccharomyces cerevisiae B5 with Coenzyme Regeneration Process

对以5%(体积比)乙醇为辅助底物的伴有辅酶再生过程的SaccharomycescerevisiaeB5不对称还原2’-氯-苯乙酮制备手性药物中间体R-2’-氯-1-苯乙醇的生物催化反应建立了描述底物消耗和产物合成的动力学模型。考察了反应过程中辅酶的种类和含量,以及底物和产物随时间的变化量。研究表明,参加反应的还原剂是辅酶Ⅰ。当底物初始浓度≤8.09mmol?L?1,可不考虑底物对微生物的毒害作用,反应可看作两个均符合顺序反应机制的氧化还原反应的耦联。通过实验数据对动力学方程式的拟合,得到动力学参数:Vm1=8.0×10?4mol?L?1?h?1,KmB1=9.0×10-4mol?L?1,KiA1=2.0×10-6mol?L?1。动力学模型模拟计算结果与实验值能较好地吻合。

R-2'-chloro-l-phenyl-ethanol was gained by asymmetric reduction of 2'-chloroacetophenone with Saccharomyces cerevisiae B5 in the presence of ethanol (5%v/v) as co-substrate. A kinetic model describing substrate consumption and product accumulation coupled with coenzymes regeneration process was proposed. The type and the content of coenzyme, and the changes of the substrate and product content vs. time during the reaction process were investigated. The results indicate that coenzyme I is reducer. The poison of organic substrate on microorganism can be ignored when substrate initial concentration is lower than 8.09 mmol &middot L-1. The whole reaction is a combination of two oxidation-reduction reactions which conform with sequence mechanisms. The model parameters obtained from the fitting of experimental data are: Vm1=8.0 × 10-4 mol &middot L-1 &middot h-1, KmB1=9.0 × 10-4 mol &middot L-1, KiA1=2.0 × 10-6 mol &middot L-1. The results of the model agree well with the experimental data.