文献类型：会议论文

英文题名：Enzymatic synthesis of cephalexin in aqueous two-phase systems

作者：Wei, DZ; Zhu, JH; Cao, XJ

机构：[1]E China Univ Sci & Technol, Inst Biochem, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China

会议论文集：7th Young Asian Biochemical Engineers Community Symposium

会议日期：OCT 28-30, 2001

会议地点：E CHINA UNIV SCI & TECHNOL, SHANGHAI, PEOPLES R CHINA

主办单位：E CHINA UNIV SCI & TECHNOL

语种：英文

外文关键词：aqueous two-phase systems; bioconversion; cephalexin; penicillin G acylase

摘要：Cephalexin was synthesized in aqueous two-phase systems (ATPSs) by using penicillin G acylase (PGA) (penicillin amidohydrolase, EC3.5.1.11) as a catalyst and 7-aminodeacetoxicephalosporanic acid (7-ADCA) and phenylglycine methyl ester (PGME) as substrates. In the ATPS composed of 20% (w/w) PEG 400 and 15% (w/w) magnesium sulfate, the partition coefficient of PGA (K-E) was less than 0.01, PGA biased to the magnesium sulfate-rich bottom phase. The partition coefficient of cephalexin (K-C) was 6.7, and the partition coefficients of PGME (K-P) and 7-ADCA (K-A) were 1.5 and 1.2, respectively. The stability of PGA in 20% (w/w) PEG 400 and 15% (w/w) magnesium sulfate ATPS was investigated. The activity of PGA was remained 80.6% after PGA was retained in the ATPS for 35 h and reserved 59% in the 20% magnesium sulfate solution at pH 7.0. When free enzyme was used for bioconversion, a high yield of cephalexin (60%) was achieved at the concentration of 100 mM 7-ADCA and 100 mM PGME in this ATPS than that of in an aqueous system (21%). (C) 2002 Elsevier Science B.V. All rights reserved.