A thermal study on the use of immobilized penicillin G acylase in the formation of 7-amino-3-deacetoxy cephalosporanic acid from cephalosporin G

Penicillin G acylase (PGA) is an important enzyme for the industrial production of 7-amino-3-deacetoxy cephalosporanic acid (7-ADCA) from cephalosporin G (Ceph-G), and 6-aminopenicillanic acid (6-APA) from penicillin G (Pen-G). These products are used for the manufacture of semi-synthetic cephalosporins and penicillins. In this study, immobilized PGA was utilized to catalyze the conversion of Ceph-G to 7-ADCA. The optimal conditions were found to be an operating temperature of 45°C, 0.2 M phosphate buffer, a substrate concentration of 30 mg cm^-3 and a catalyst particle concentration of 0.01 g cm^-3 (specific activity of 623.2 U g^-1). Up to 45°C the reaction was characterized by an activation energy of 38.66 kJ mol^-1. Beyond 57.5°C there was a sharp decline of activity, characterized by a deactivation energy of 235.88 kJ mol^-1.