α-Amylase immobilized on bulk acoustic-wave sensor by UV-curing coating

Abstract

A new method for immobilization of α-amylase by UV-curing coating is proposed in this paper. The immobilization procedure of UV-curing coating on piezoelectric quartz crystal is simple and convenient, and causes less loss of enzymatic activity. The activity of the immobilized α-amylase is monitored by a technique based on bulk acoustic-wave (BAW) sensor. The frequency shift of BAW sensor can reflect the degree of hydrolysis of starch by the immobilized α-amylase. It is appropriate for the immobilized α-amylase to hydrolyze the soluble starch under pH 7.0 condition, which is similar to that of the free α-amylase. Kinetic parameters (the Michaelis constant, K m, and the maximum initial rate V max) of the enzymatic hydrolysis of starch by the immobilized α-amylase are estimated by using a linear method of Lineweaver–Burk plot. K m=12.7 mg ml −1 and V max=15.9 Hz min −1. And the experimental results show that the immobilized α-amylase entrapped by the UV-curing coating retains adequate enzymatic activity and can be reused more than 50 times under certain experimental conditions.