Merging Consecutive PET Processes within a Metal–Organic Cage for Abiotic–Biotic Combined Photocatalytic Biomass Reforming

Abstract

Combining abiotic photocatalytic modules with enzymatic conversion to reform biomass represents a compelling way for sustainable energy schemes but faces marked challenges on the electron and proton transport corresponding to the cofactor regeneration and shuttling between biotic and abiotic partners. Herein, we report a consecutive photoinduced electron-transfer approach to reform biomass into fuels and active H-source for nitroarene reduction by grafting a cage-dye-NADH (nicotinamide adenine dinucleotide) clathrate with glucose dehydrogenase (GDH). Under light irradiation, the cage-dye-NADH clathrate acts as a photoactive relay to conduct two photoinduced 1e^– electron-transfer reactions consecutively with a 2e^– oxidation of NADH to NAD⁺, guaranteeing an orderly path related to cofactor regeneration. When the clathrate is positioned inside the pocket of GDH to join a biotic NAD⁺-mediated synthesis, the metal–organic artificial enzyme facilitates fast cofactor generation and shuttling between the artificial clathrate and the native enzyme within one working module. The grafting enzyme combines artificial photocatalysis and enzymatic dehydrogenation to endow an efficient conversion of biomass feedstocks into green H-source, innovating a unique paradigm for the sustainable energy scheme that combines energy of two photons in one turnover cycle. The superiority of the grafting enzyme allows the direct hydrogenation and reduction of fine chemicals and enables tandem nitroarene reduction with a turnover number reaching 15,000, providing a distinguished avenue for biomass utilization and solar energy conversion.