A multienzyme system immobilized on surface-modified metal–organic framework for enhanced CO2 hydrogenation

Abstract

Hydrogenating carbon dioxide to formate using formate dehydrogenase (FDH) is a sustainable approach for CO₂ mitigation. Herein, we developed a biocatalytic system with cofactor regeneration by immobilizing multiple enzymes, namely FDH, carbonic anhydrase (CA), and glutamate dehydrogenase (GDH), on a hydrophobic surface modified MOF, SA-HKUST-1. The adsorption kinetics of the multiple enzymes on the SA-HKUST-1 surface were described using pseudo second-order model, while the equilibrium followed Freundlich isotherm. Formate production by the enzymes immobilized on SA-HKUST-1 was 3.75 times higher than that achieved by free enzymes and 8.4 times higher than that of FDH immobilized alone on SA-HKUST-1. The hydrophobic interaction between the enzymes and the support altered the secondary structure of enzymes, and the immobilized enzymes retained 94% of their activity after four reuse cycles. This study provides novel insights into the combined effect of hydrophobic support and multiple enzymes on the catalytic efficiency and stability of FDH. These findings can provide a basis for developing a highly stable biocatalytic system with cofactor regeneration for continuous hydrogenation of CO₂ to formate at the industrial level.