Some factors affecting the immobilization of penicillin G acylase on calcined layered double hydroxides

A new type of support, calcined layered double hydroxides (CLDH), has been used to immobilize penicillin G acylase. The effect of varying the composition of the layered double hydroxide precursor and the calcination temperature on the activity of the immobilized enzyme has been studied. The activity of the immobilized enzyme decreased with increasing Mg/Al molar ratio of the CLDH. Mg/Al-CLDH had a higher affinity for the enzyme than Zn/Al-CLDH, but a lower percentage expressed activity. The activity of the immobilized enzyme was a maximum when the calcination temperature was between 450 and 550°C. The amount of enzyme adsorbed by the support shows a close correlation with its surface area. Immobilization of the enzyme on the support increases the acid resistance of the former.