ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Immobilization of modified penicillin G acylase on Sepabeads carriers

Milena Žuža, Nenad Milosavić, and Zorica Knežević-Jugović

Department of Biochemical Engineering, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia

E-mail: milenazuza@yahoo.com

Received: 15 June 2008  Revised: 13 October 2008  Accepted: 20 October 2008

Abstract: An approach to stable covalent immobilization of chemically modified penicillin G acylase from Escherichia coli on Sepabeads® 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® EC EA and Sepabeads® 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.

Keywords: penicillin G acylase - modification - immobilization - Sepabeads carriers

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-009-0012-z

Chemical Papers 63 (2) 117–124 (2009)