A novel method for the immobilization of glucoamylase onto polyglutaraldehyde-activated gelatin

Abstract

A novel method was developed for the immobilization of glucoamylase from Aspergillus niger. The enzyme was immobilized onto polyglutaraldehyde-activated gelatin particles in the presence of polyethylene glycol and soluble gelatin, resulting in 85% immobilization yield. The immobilized enzyme has been fully active for 30 days. In addition, the immobilized enzyme retained 90 and 75% of its activity in 60 and 90 days, respectively. The enzyme optimum conditions were not affected by immobilization and the optimum pH and temperature for free and immobilized enzyme were 4 and 65 degrees C, respectively. The kinetic parameters for the hydrolysis of maltodextrin by free and immobilized glucoamylase were also determined. The K. values for free and immobilized enzyme were 7.5 and 10.1 g maltodextrin/l, respectively. The V-max values for free and immobilized enzyme were estimated as 20 and 16 mu mol glucose/(min mu 1 enzyme), respectively. The newly developed method is simple yet effective and could be used for the immobilization of some other enzymes. (c) 2007 Elsevier B.V. All rights reserved.