Enzymatic synthesis of cefaclor from 7-aminodesacetoxymethyl-3-chlorocephalosporainc acid(6-ACCA) and phenylglycine derivatives using penicillin G acylase was studied .Many factors that affect the conversion of 7-ACCA...Enzymatic synthesis of cefaclor from 7-aminodesacetoxymethyl-3-chlorocephalosporainc acid(6-ACCA) and phenylglycine derivatives using penicillin G acylase was studied .Many factors that affect the conversion of 7-ACCA to cefaclor were examined.The immobilized enzyme from Bacillis megaterium gave a better catalytic properties and the higher conversion was obtained using phenylglycine methyl ester(PGME) as acyl donor.And the external mass transfer limitation could be eliminated when the stirring rate was more than 150r/min.Low temperature was beneficial for the synthesis and the results showed that the synthetase activity was hardly influenced by temperature while the amidase activity was affected greatly by temperature.The optimum reaction conditions were determined at pH 6.5 and 10℃,respectively.The best 7-ACCA conversion of 56% was achieved when the intial concentration of 7-ACCA and PGME was at 50 mM and 150mM,respectively.展开更多
文摘目的酶法合成头孢克洛工艺优化并回收套用母液中的头孢克洛。方法采用酶催化法，以7-氨基-3-氯-头孢烯酸（7-amino-3-chloro-3-cephem-4-carboxylicacid，7-ACCA）为母核，苯甘氨酸甲酯（D—phenylglycine methyl ester,PGM）为酰基供体，在水相中用固定化青霉素酰化酶（penicillin G acylase，PGA）催化合成头孢克洛（cefaclor）。对投酶量、侧链与底物投料比、反应温度、反应pH、反应时间及母液中头孢克洛的回收套用等条件进行优化，考察头孢克洛摩尔收率及产品质量。结果工艺优化后头孢克洛摩尔收率75％以上，套用回收母液中的头孢克洛后摩尔收率80％以上，高于目前化学法的收率（65％～70％），产品质量合格。结论酶法合成头孢克洛工艺反应条件温和，收率高，排放废水中仅含有一些简单的无机盐，对环保无压力，属于绿色合成工艺。
文摘Enzymatic synthesis of cefaclor from 7-aminodesacetoxymethyl-3-chlorocephalosporainc acid(6-ACCA) and phenylglycine derivatives using penicillin G acylase was studied .Many factors that affect the conversion of 7-ACCA to cefaclor were examined.The immobilized enzyme from Bacillis megaterium gave a better catalytic properties and the higher conversion was obtained using phenylglycine methyl ester(PGME) as acyl donor.And the external mass transfer limitation could be eliminated when the stirring rate was more than 150r/min.Low temperature was beneficial for the synthesis and the results showed that the synthetase activity was hardly influenced by temperature while the amidase activity was affected greatly by temperature.The optimum reaction conditions were determined at pH 6.5 and 10℃,respectively.The best 7-ACCA conversion of 56% was achieved when the intial concentration of 7-ACCA and PGME was at 50 mM and 150mM,respectively.
