Immobilization of glucose oxidase on porous copolymer

Porous copolymer was prepared by suspension polymerization method of styrene, maleic anhydride and divinylbenzene in a batch type reactor. The characteristics of the copolymer were evaluated using Fourier Transform IR spectroscopy and scanning electron microscopy. The glucose oxidase (GOD) enzyme was selected as a model enzyme to assess its potential applicability for immobilization purpose. Then the glucose oxidase was immobilized on a copolymer under an optimized condition (the incubation time, and pH 6,5, GOD 5 mg/ml). Enzymatic activities of free and immobilized GOD were assessed in terms of the oxidation of D-glucose to D-gluconic acid carried out under stirring by air. The enzyme immobilization yield was 87% with the immobilized GOD activity of 125 U/mg protein. The Michaelis constant for immobilized GOD was disclosed to be 16,3 mmol/l by Lineweaver–Burk plot at 25C. The highest enzymatic activity was achieved when the pH of the medium was approximately pH 7.0. Storage stabilities of GOD samples were investigated during 40 days and the retained activity was 70%, higher than the 22% of the free enzyme.