Co-immobilization of bienzyme HRP/GOx on highly stable hierarchically porous MOF with enhanced catalytic activity and stability: Kinetic and thermodynamic studies

Abstract

Immobilization of enzymes onto solid carriers usually results in the reduction of enzyme catalytic activity. To solve this tricky problem, we proposed a novel strategy by accurately constructing the micro-mesoporous channel structure of highly stable hierarchically porous metal-organic framework (HP-Zr-MOF) for co-immobilization of horseradish peroxidase (HRP) and glucose oxidase (GOx). Notably, the precise construction and co-regionalization of HP-Zr-MOF with hierarchical structure can efficiently suppress enzyme leaching and significantly improve the catalytic efficiency, enzyme activity and the affinity for substrates of co-immobilized bienzyme reactor (GOx&HRP@HP-Zr-MOF). The Km value for GOx&HRP@HP-Zr-MOF was 0.2050 mM, which was 0.66-fold less than that of free GOx&HRP, while the Ka value for GOx&HRP@HP-Zr-MOF was superior to that of free GOx&HRP, manifesting the affinity of GOx&HRP@HP-Zr-MOF for substrates strengthened. Importantly, the GOx&HRP@HP-Zr-MOF exhibited favorable stability and reusability, maintaining 97.4% of the original activity after 1 h incubation at 60 °C and over 90% initial activity after 30 cycles. Moreover, the GOx&HRP@HP-Zr-MOF was applied to the colorimetric detection of glucose, manifesting outstanding detection capability. Finally, the GOx&HRP@HP-Zr-MOF exhibited excellent catalytic efficiency for the degradation of 2,4-dichlorophenol, which indicated that the bio-catalytic material has potential practical application value in wastewater treatment.