Horseradish peroxidase (HRP) and glucose oxidase (GOX) based dual-enzyme system: Sustainable release of H2O2 and its effect on the desirable ping pong bibi degradation mechanism

In this study, an adaptable HRP/GOX-Glu system was established due to the trait, efficient degradation of pollutants in the catalytic process of HRP named the ping-pong bibi mechanism and a sustained release of H2O2 in-situ under the catalysis of glucose oxidase (GOX). Compared with the traditional HRP/H2O2 system, the HRP was more stable in the HRP/GOX-Glu system based on the feature of persistent releasing H2O2 in-situ. Simultaneously, the high valent iron was found out to give a greater contribution to Alizarin Green (AG) removal through ping-pong mechanism, whereas the hydroxyl radical and superoxide free radical generated by Bio-Fenton were also the main active substances for AG degradation. Furthermore, on the basis of effect evaluation of the co-existence of two different degradation mechanisms in the HRP/GOX-Glu system, the degradation pathways of AG were proposed. Moreover, the optimum reaction conditions preferentially triggering ping-pong bibi mechanism instead of Bio-Fenton were determined by single factor analysis and degradation mechanism elaboration. This study would provide a reference for how to give full play to the advantages of ping-pong bibi mechanism in the dual-enzyme system based on HRP to degrade pollutants with high efficiency.