Immobilization of modified penicillin G acylase on Sepabeads carriers

An approach to stable covalent immobilization of chemically modified penicillin G acylase from Escherichia coli on Sepabeads(R) carriers with high retention of hydrolytic activity and thermal stability is presented. The two amino-activated polymethacrylate particulate polymers with different spacer lengths used in the study were Sepabeads(R) EC EA and Sepabeads(R) EC HA. The enzyme was first modified by cross-linking with polyaldehyde derivatives of starch in order to provide it with new useful functions. Such modified enzyme was then covalently immobilized on amino supports. The method seems to provide a possibility to couple the enzyme without risking a reaction at the active site which might cause the loss of activity. Performances of these immobilized biocatalysts were compared with those obtained by the conventional method with respect to activity and thermal stability. The thermal stability study shows that starch-PGA immobilized on Sepabeads EC-EA was almost 4.5-fold more stable than the conventionally immobilized one and 7-fold more stable than free non-modified PGA. Similarly, starch-PGA immobilized on Sepabeads EC-HA was around 1.5-fold more stable than the conventionally immobilized one and almost 9.5-fold more stable than free non-modified enzyme. (C) 2008 Institute of Chemistry, Slovak Academy of Sciences