Studies on the co-immobilized GOD/CAT on cross-linked chitosan microsphere modified by lysine

Glucose oxidase (GOD) and catalase (CAT) were co-immobilized on a novel crosslinked chitosan resin modified by l-lysine. The immobilized system exhibited the best performance when the immobilization process was conducted at 4 °C for 3 h with GOD/CAT activity ratio of 1:18 and pH 7.0. Under the optimum pH 4.0 and temperature 40 °C, the enzyme system could achieve to the maximum conversion of glucose, which was 68.9%. Acidoresistance and thermotolerance of the enzymes were both strengthened. The Km of the co-immobilized enzyme system obtained in this study was 31.02 mM. The GOD enzyme immobilized in this system could maintain 94% of initial activity after the 12th operational cycle. 95.8% of initial activity was left after 50 weeks’ storage at 4 °C. GOD achieved better performance in this new immobilized enzyme system due to its effective elimination of H2O2, which showed potential applications for various commercial uses.