Screening Of Microbial Epoxide Hydrolase Strains And Study On It’s Kinetic Resolution Of Glycidyl Phenyl Ether

Aryl glycidyl ethers are very important pharmaceutical intermediates, and have been widely applied in the preparation of aryloxypropanolamines, which areβ-adrenergic blocking agents and important drugs for the treatment of hypertension,angina pectoris,glaucoma,anxiety and obesity.The kinetic resolution of racemic epoxide by epoxide hydrolases（EH, EC 3.3.2.3）,a kind of cofactor-independent enzymes and is almost ubiquitous in nature,has wider range substrate and was demonstrated to be a powerful method to obtain optical pure epoxide.Strain Bacillus megaterium ZJUZQ001 which could enantioselectively hydrolysis the racemic glycidyl phenyl ethers,has been isolated from the soils which were collected from chemical plant in Hangzhou.The conditions of enzyme production were studied,include carbon source and the appropriate culture medium ingredients were 10.0g·L^-1 sucrose, 10.0g·L^-1 yeast extract,10.0g·L^-1 NaCl,0.5g·L^-1 CaCl₂,2.8g·L^-1 K₂HPO₄·3H₂O,1.1g·L^-1 KH₂PO₄,pH 7.0.Furthermore,the condition for GPE hydrolysis is also optimized, including time,temperature,buffer type,ion strength and substrate concentration.As compared with other buffers,borate buffer（100mmol/L, pH 8.2） was considered as optimal buffer system,which was found to be able to increase e.e._s from 90%to＞99.5%,E from 25 to 45.6.Other types nucleophilic ring opening reaction catalysed by epoxide hydrolase of glycidyl phenyl ether were studied.The enzyme catalytic activity for different types of nucleophiles were comparied,and analysised the amine reaction conditions.The results showed that the reaction of n-hexane was the most suitable solvent system.