Faculty of Food Technology and Biotechnology, University of Zagreb
Abstract
Cephalexin (CEX) was synthesized with 7-amino-3-deacetoxycephalosporanic acid (7-ADCA) and D(–)-phenylglycine methyl ester (PGME) using immobilized penicillin G acylase from Escherichia coli. It was found that substrate concentration and in situ product could remarkably influence the ratio of synthesis to hydrolysis (S/H) and the efficiency of CEX synthesis. The optimal ratio of enzyme to substrate was 65 IU/mM 7-ADCA. High substrate concentration improved the 7-ADCA conversion from 61 to 81 % in the process without in situ product removal (ISPR), while in the synthetic process with ISPR, high substrate concentration increased the 7-ADCA conversion from 88 to 98 %. CEX was easily separated from CEX/β-naphthol complex and its purity and overall yield were 99 and 70 %, respectively.Primjenom imobilizirane Penicilin-G-acilaze iz bakterije Escherichia coli sintetiziran je cefaleksin (CEX) iz 7-amino-3-deacetoksicefalosporanske kiseline (7-ADCA) i D(-)-fenilglicin-metilnog estera (PGME). Koncentracije supstrata i produkta in situ mogu znatno utjecati na omjer sinteze i hidrolize (S/H) i djelotvornost sinteze cefaleksina. Optimalni omjer enzima i supstrata iznosio je 65 IU/mM 7-ADCA. Velika koncentracija supstrata poboljšala je konverziju 7-ADCA sa 61 na 81 % u procesu bez uklanjanja produkta in situ (ISPR), a s 88 na 98 % u procesu sa ISPR. Cefaleksin je lako uklonjen iz kompleksa CEX/β-naftol, a dobiveni je proizvod imao čistoću od 99 % i ukupni prinos od 70 %
