A dual-enzyme microreactor based on encapsulation and covalent bond for enzymatic electrocatalytic CO2 reduction

Abstract

Enzymatic reduction of CO2 into high-value chemicals has become an emerging technology attributed to its high selectivity and catalytic efficiency under mild conditions. While, the low solubility of CO2 at room temperature, the expensive cofactors and the poor stability of free enzyme limit the application potential. To solve these problems, we used organic microcapsules together with MOF to protect formate dehydrogenase (FDH) by encapsulation and carbonic anhydrase (CA) by covalent bond with high CO2 capture ability to construct a dual-enzyme microreactor. Besides, the additional mesopores of the microreactor can ensure the efficient internal diffusion of the substrate and product. Electron mediator was used to enhance electrocatalytic NADH regeneration to efficiently reduce CO2 to formate in the enzyme electrocatalysis system. After optimization, the highest yield of formate in the electrocatalytic CO2 reduction system by the dual enzyme microreactor was 2.917 mM with a generation rate of 1.296 × 104 μmol gcat-1h−1, which was 8.9 times higher than free enzyme.