A novel bienzymatic bioreactor based on magnetic hierarchical porous MOF for improved catalytic activity and stability: Kinetic analysis, thermodynamics properties and biocatalyst applications

Metal-organic frameworks (MOFs) have been regarded as ideal carriers for enzyme immobilization owing to their unique structural characteristics. Whereas, enzyme activity and catalytic efficiency are seriously influenced owing to the conformation change of enzyme molecules during immobilization and the increase of substrate mass transfer resistance during catalysis. Herein, for the first time, we designed a novel magnetic hierarchical micro -and mesoporous metal-organic framework (mH-UiO-66(Zr)) as a platform for co-immobilizing horseradish peroxidase (HRP) and glucose oxidase (GOx). The obtained mH-UiO-66(Zr) with magnetic performance and hierarchical structure can effectively inhibit enzyme leakage, and reduce the material loss caused by centrifu-gation and the mass transfer resistance of substrate. Notably, the bienzyme bioreactor (GOx&HRP@mH-UiO-66 (Zr)) was accurately constructed online in situ by microcalorimetry, which exhibited outstanding catalytic ef-ficiency and superior stability against organic solvents, pH and temperature and favourable reusability, main-taining 95.1% of the original activity after 1 h incubation at 70 degrees C and over 90% initial activity after 15 cycles. Kinetics and thermodynamics investigation revealed the enhanced affinity of GOx&HRP@mH-UiO-66(Zr) for substrates. Furthermore, GOx&HRP@mH-UiO-66(Zr) has been utilized for the rapid detection and efficient degradation of 2,4-dichlorophenol (2,4-DCP), ensuring bio-catalytic material a bright potential application in environmental remediation.