Immobilization of α-amylase on Cu2+ chelated poly(ethylene glycol dimethacrylate-n-vinyl imidazole) matrix via adsorption


Kara A., Osman B., Yavuz H., Besirli N., Denizli A.

Reactive and Functional Polymers, vol.62, no.1, pp.61-68, 2005 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 62 Issue: 1
  • Publication Date: 2005
  • Doi Number: 10.1016/j.reactfunctpolym.2004.08.008
  • Journal Name: Reactive and Functional Polymers
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.61-68
  • Keywords: enzyme immobilization, alpha-amylase, chelating beads, n-vinyl imidazole, beads, METHACRYLATE) MEMBRANES, AFFINITY ADSORBENT, METAL, GLUCOAMYLASE, PURIFICATION, INVERTASE

Abstract

Poly(ethylene glycol dimethacrylate-n-vinyl imidazole) [poly(EGDMA-VIM)] hydrogel (average diameter 150-200 μm) was prepared by copolymerizing ethylene glycol dimethacrylate (EGDMA) with n-vinyl imidazole (VIM). The copolymer hydrogel bead composition was characterized by elemental analysis and found to contain 5 EGDMA monomer units each VIM monomer unit. Poly(EGDMA-VIM) beads had a specific surface area of 59.8 m2/g. Poly-(EGDMA-VIM) beads were characterized by swelling studies and SEM. Cu2+ ions were chelated on the poly(EGDMA-VIM) beads, then these beads were used in the adsorption of α-amylase from Aspergillus Oryzae in batch system. The maximum α-amylase adsorption capacity of the poly(EGDMA-VIM)-Cu 2+ beads was observed as 38.9 mg/g at pH 4.0. The Km values for immobilized α-amylase (poly(EGDMA-VIM)-Cu2+) (22.5 mM) was higher than that of free enzyme (15.8 mM). Storage stability was found to increase with immobilization. It was observed that enzyme could be repeatedly adsorbed and desorbed without significant loss in adsorption capacity or enzyme activity. © 2004 Elsevier B.V. All rights reserved.