In this work, a new way for enzyme immobilization was explored and properties of the enzyme immobilized on different polymer films were investigated. In the process, a polystyrene-based diazonium salt (PS-DAS) was synthesized and used as molecular adhesive to immobilize beta-glucosidase on the polymeric supports (films of polyethylene, polypropylene and poly(ethylene terephthalate)). The immobilization of beta-glucosidase on the polymer surfaces was achieved by sequential depositions of a piece of the polymer films in PS-DAS and the enzyme solutions. The surface modification was investigated by X-ray photoelectron spectroscopy (XPS), water contact angle measurement, and atomic force microscopy (AFM). The activity of the immobilized beta-glucosidase was evaluated by measuring its enzymatic activity to the hydrolysis of p-nitrophenyl-beta-D-glucopyranoside (pNPG). The optimized reaction conditions (such as pH and temperature), thermal stability, and reusability of the immobilized enzyme on PE films were assayed by using the enzyme-catalyzed reaction. Results show that the polymeric diazonium salt is firmly adhered on the polymer surfaces and the modified surfaces can react with the enzyme to form covalent bonds. The immobilized enzyme shows changes in the optimized pH and temperature for the hydrolysis reaction catalyzed by beta-glucosidase. The kinetic parameter (K-m) of the immobilized beta-glucosidase is lower than that of its free counterpart. The immobilized enzyme shows significant enhancement in the thermal stability and reasonable reusability. This new approach can be used as a simple and versatile method for protein immobilization. (C) 2010 Elsevier Ltd. All rights reserved.