Immobilization of diastase α-amylase on nano zinc oxide

Diastase α-amylase extracted from malt, catalyses break down of starch into maltose. It is commonly used in food and fermentation industry. In the present study nano zinc oxide is used as support for this starch hydrolyzing enzyme. IR study revealed that the enzyme got adsorbed via electrostatic interaction with the functional groups on the support. The immobilized enzyme possessed a better heat-resistance than free enzyme. The kinetic parameters were determined using Lineweaver-Burk plot. The immobilized enzyme showed higher Km 2.08 mg/ml than the free enzyme whose Km is 0.45 ± .05 mg/ml. The Vmax of immobilized enzyme was about 2.92 ± .02 mg/ml/min and that of free enzyme was 7.14 ± .02 mg/ml/min, showing decrease in activity after immobilization. The immobilized enzyme showed 70% activity after 30 days of storage while free enzyme lost its activity within 7 days. About 80% of enzyme retained activity after 4 cycles of reuse.