A series of ethylene oxide (EO)-propylene oxide (PO) randomco-polymers (EOPO) were used to form aqueous two-phase systems (ATPS)with ammonium sulfate. Effects of EOPO's properties on the phaseseparation behaviors ...A series of ethylene oxide (EO)-propylene oxide (PO) randomco-polymers (EOPO) were used to form aqueous two-phase systems (ATPS)with ammonium sulfate. Effects of EOPO's properties on the phaseseparation behaviors and on the partition of cephalexin and7-aminodesacetoxicephalosporanic acid (7-ADCA) in ATPS wereinvestigated. Both the molar mass and molar ratio of EO to PO of EOPOcould greatly influence partition behaviors of cephalexin and 7-ADCAas well as the binodal curve of ATPS.展开更多
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
基金Supported by the National Natural Science Foundation of China (No. 29873014) and the Key Disciplinary Foundation of Shanghai.
文摘A series of ethylene oxide (EO)-propylene oxide (PO) randomco-polymers (EOPO) were used to form aqueous two-phase systems (ATPS)with ammonium sulfate. Effects of EOPO's properties on the phaseseparation behaviors and on the partition of cephalexin and7-aminodesacetoxicephalosporanic acid (7-ADCA) in ATPS wereinvestigated. Both the molar mass and molar ratio of EO to PO of EOPOcould greatly influence partition behaviors of cephalexin and 7-ADCAas well as the binodal curve of ATPS.
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.
