Enhancing the catalytic performance of chloroperoxidase by co-immobilization with glucose oxidase on magnetic graphene oxide

Although chloroperoxidase (CPO) has long been recognized as a powerful and versatile catalyst, its applications have been thwarted by the difficulty in regenerating the active enzyme and substrate (peroxide) induced protein inactivation. In this paper, we describe the fabrication and characterization of chloroperoxidase (CPO) and glucose oxidase (GOx) on the surface of MGO. The performance of the immobilized CPO was considerably enhanced by coupling with GOx that provided the required H2O2 in situ through glucose oxidation. The activity of MGO-GOx-CPO (96.6%) towards the decolorization of orange G was much superior to that of MGO-GOx+MGO-CPO (86.2%), probably as a result of reduced mass transfer resistance between CPO and H2O2 generated from GOx molecules. Interestingly, MGO-GOx-CPO reached its peak activity (95.2%) when temperature was maintained between 42 degrees C and 50 degrees C compared to the optimal temperature of 35 degrees C for the free enzyme, possibly due to dispersion of the otherwise stacked MGO below 42 degrees C. Finally, MGO-GOx-CPO can be conveniently reused for its ease of recovery in the presence of an external magnetic field, with similar to 38.5% activity remained after 6 cycles of applications. This work demonstrates the feasibility of co-immobilizing CPO and GOx onto MGO and the potential of MGO-GOx-CPO in environmental applications.