Waste-to-wealth in photo-biocatalysis: Sustaining and enhancing oxidase activation for 5-hydroxymethylfurfural oxidation in pure water via Au/TiO2-driven in-situ H2O2 decomposition and ROS generation

Developing a novel EPCS combining GOase with Au/TiO 2 . • Achieving ∼92.3% DFF yield with ∼97.0% selectivity within 2 h in pure water. • The by-product H 2 O 2 is in-situ decomposed into O 2 by Au/TiO 2 . • •OH, •O 2 – and O 2 precisely required for GOase activation generated by Au/TiO 2 . 2,5-Diformylfuran (DFF), as the oxidation product of the biomass platform molecule 5-hydroxymethylfurfural (HMF), has attracted considerable attention because of its broad utility as a precursor for pharmaceuticals, renewable polymers, and other functional products. Efficient oxidation of HMF into DFF through biocatalysis in pure water is extremely desirable but still faces significant challenges: complex multi-enzyme systems and low reaction efficiency. Herein, we develop a novel enzyme-photo-coupled catalytic system (EPCS) combining GOase with Au/TiO 2 photocatalyst, achieving “waste-to-wealth”. The mechanism study reveals that the Au/TiO 2 acts as the role of “killing two birds with one stone”: in-situ decomposing inhibitory H 2 O 2 by-product into O 2 and H 2 O, thereby mitigating enzyme inhibition; and ingeniously generating reactive oxygen species (ROS) (hydroxyl radicals (·OH) and superoxide radicals ( $$ )) and regenerative O 2 that precisely are required for GOase activation. Under visible light conditions, the EPCS achieves (92.3±1.4)% DFF yield with (97.0±0.8)% selectivity within 2 h, significantly outperforming the single enzyme system (DFF yield: (40.9±2.4)%). The “green chemistry” concept is implemented in the EPCS, which provides a generalizable strategy for developing efficient, green, and concise oxidation systems by turning a toxic by-product into catalytic promoters. Download: Download high-res image (335KB) Download: Download full-size image