Immobilization studies and biochemical properties of free and immobilized Candida Rugosa lipase onto hydrophobic group carrying polymeric support

Abstract

In this study, the hydrophobic group carrying support was prepared for the immobilization of Candida rugosa lipase through the reversible adsorption method. Epoxy groups containing poly(glycidyl methacrylate-methyl methacrylate-ethylene glycol dimethacrylate) (poly(GMA-MMA-EGDMA)) beads were synthesized by suspension polymerization, and the reactive epoxy groups of poly(GMA-MMA-EGDMA) beads were treated with ammonia while glutaraldehyde was used as a coupling agent. After the L-hydrophobic ligand phenylalanine amino acid was covalently attached on the activated polymeric matrix, the lipase enzyme was immobilized. The immobilization efficiency as a function of adsorption parameters was characterized. The maximum lipase immobilization capacity of the poly(GMA-MMA-EGDMA) beads was 68.25 mg/g. The activities of the free and immobilized enzymes were investigated in the hydrolysis reaction of olive oil. The activities of the free and the immobilized lipases were measured at different pH values and temperatures, and their thermal and storage stabilities were also determined. The optimum pH for immobilized lipase was 6.0, which was the same for free enzymes. In this pH value, the retained activity of immobilized lipase was 91.84%. The optimum activity temperatures of free and immobilized lipases were determined as 35 and 45 A degrees C, respectively. The optimum temperature for the lipase immobilized on the hydrophobic group carrying matrix was 10 A degrees C higher and it demonstrated activity in a broader temperature range than that of the free enzyme. The immobilized lipase had better resistance to temperature inactivation than the free form. The free enzyme lost all of its activity during the 28 days storage period, while immobilized lipase lost 34% of its activity during the 56 days storage period.