Immobilization of penicillin acylase from Escherichia coli on commercial sepabeads EC-EP carrier

This paper describes the covalent immobilization of penicillin G acylase from Escherichia coli on sepabeads EC-EP, an epoxy-activated polymethacrylic carrier and kinetic properties of the immobilized enzyme. The selected enzyme belongs to a class of biocatalysts whose industrial interest is due to their versatility to mediate hydrolysis of penicillins and semi-synthetic ?-lactam antibiotics synthesis reactions. About 2.7 mg of the pure enzyme was immobilized onto each gram of sepabeads with an enzyme coupling yield of 96.9%. However, it seems that the activity coupling yield is not correlated with the amount of enzyme bound and the maximum yield of 89.4% can be achieved working at low enzyme loading (0.14 mg g-1). Immobilization of the penicillin acylase resulted in slightly different pH activity profile and temperature optima, indicating that the immobilization by this method imparted structural and conformational stability of this enzyme. It appears that both free and immobilized penicillin acylase followed simple Michaelis-Menten kinetics, implying the same reaction mechanism in both systems.