Activity of diastase α-amylase immobilized on polyanilines (PANIs)

Starch hydrolysing enzyme a-amylase (EC 3.2.1.1) was immobilized by physical adsorption and covalent binding onto chemically synthesised polymer, polyanilines (PANIs) in two different forms, emeraldine salt and emeraldine base powder. The immobilization efficiency was affected by the pH of the immobilization medium, contact time and amount of enzyme. The kinetic parameters, reusability and storage stability of the enzyme were studied under free and immobilized condition at optimum pH and temperature. The immobilized enzyme showed enhanced storage stability over a period of 6 months, while free enzyme in solution lost all of its activity within a period of 8 days. Reusability of the enzyme was improved by immobilization. The K-m values for starch hydrolysis were found to be high for the immobilized enzymes. (C) 2011 Elsevier Ltd. All rights reserved.