Immobilization of Aspergillus oryzae beta-Galactosidase onto Duolite A568 Resin via Simple Adsorption Mechanism

Abstract

In this study, a rapid, simple and economic method of enzyme immobilization was developed to hydrolyze lactose. Duolite A568 resin was used for the immobilization of beta-galactosidase via simple adsorption mechanism. The effects of immobilization parameters such as time, pH, and temperature were studied. Immobilization parameters for maximum enzyme activity were estimated at 35 A degrees C temperature, pH 4.5, 5 mg/mL enzyme concentration, and approximately 60 min immobilization time. A significant amount of enzyme was immobilized with high catalytic activity. Enzyme immobilization procedure explained in this study slightly affected the enzyme kinetic. The value of Michaelis constant K (m) for immobilized enzyme was significantly larger, indicating decreased affinity by the enzyme for its substrate. It was observed that both free and immobilized enzyme showed maximum activity at 65 A degrees C reaction temperature. Immobilized beta-galactosidase was significantly more active at all temperatures as compared to its free form. However, optimal pH of immobilized enzyme was slightly affected by immobilization procedure. The optimum pH of immobilized enzyme was shifted up 0.5 unit to a more alkaline value of 6.0 compared to the free enzyme.