Preparation of enzyme nanoparticles and studying the catalytic activity of the immobilized nanoparticles on polyethylene films

Using high-intensity ultrasound, in situ generated alpha-amylase nanoparticles (NPs) were immobilized on polyethylene (PE) films. The alpha-amylase NP-coated PE films have been characterized by E-SEM, FTIR, DLS, XPS and RBS. The PE was reacted with HNO3 and NPs of the alpha-amylase were also deposited on the activated PE. The PE impregnated With alpha-amylase (4 mu g per 1 mg PE) was used for hydrolyzing soluble potato starch to maltose. The immobilization improved the catalytic activity of alpha-amylase at all the reaction conditions studied. The kinetic parameters, K-m (5 and 4 g L-1 for the regular and activated PE, respectively) and V-max (5 x 10(-7) mol ml(-1) min(-1), almost the same numbers were obtained for the regular and activated PEs) for the immobilized amylase were found to slightly favor the respective values obtained for the free enzyme (K-m = 6.6,g L-1, V-max = 3.7 x 10(-7) mol ml(-1) min(-1)). The enzyme remained bound to PE even after soaking the PE in a starch solution for 72 h and was still found to be weakly active. (C) 2012 Elsevier B.V. All rights reserved.