立体选择性羧酸酯酶产生菌的筛选及发酵优化

The Screening and Fermentation Optimization of a Carboxyl Esterase-Producing Strain with High Stereoselectivity

从多地区采集的土样中筛选得到了一株产羧酸酯水解酶的菌株,它能够高立体选择性水解乙拉西坦中间体甲酯(α-乙基-2-氧合-1-吡咯烷乙酸甲酯).通过观察该菌株的菌落形态、生理生化特征,结合16SrDNA测序分析,该菌株被鉴定为鞘氨醇杆菌SIT102.通过该菌种发酵条件的优化,得到其最佳的发酵培养条件.利用鞘氨醇杆菌整细胞催化拆分外消旋乙拉西坦中间体甲酯的转化率、产物的对映体过量值(ee_p)及对映体选择率(E值)分别达到48.3%、96.5%和176.

A strain producing carboxyl esterase which could hydrolyze Levetiracetam intermediate methyl ester（α-ethyl-2-O-1-pyrrolidinyl acetic acid methyl ester）was successfully obtained from the soils.By examining to the patterns of colony,its physio-biochemical characteristics and 16 SrDNA analysis,the strain was identified as Sphingobacterium sp.SIT102. The optimum fermentation conditions of Sphingobacterium sp.SIT102 were optimized.For the resolution of racemic etiracetam intermediate methyl ester by whole cells of Sphingobacteriumsp.SIT102,the conversion,ee value of product（ee_p）and Enantiomeric ratio（Evalue）were 48.3%,96.5% and 176,respectively.