One‐Pot Enzyme Cascade for Controlled Synthesis of Furancarboxylic Acids from 5‐Hydroxymethylfurfural by H2O2 Internal Recycling

Furancarboxylic acids are promising biobased building blocks in pharmaceutical and polymer industries. In this work, dual‐enzyme cascade systems composed of galactose oxidase (GOase) and alcohol dehydrogenases (ADHs) are constructed for controlled synthesis of 5‐formyl‐2‐furancarboxylic acid (FFCA) and 2,5‐furandicarboxylic acid (FDCA) from 5‐hydroxymethylfurfural (HMF), based on the catalytic promiscuity of ADHs. The byproduct H2O2, which is produced in GOase‐catalyzed oxidation of HMF to 2,5‐diformylfuran (DFF), is used for horseradish peroxidase (HRP)‐mediated regeneration of the oxidized nicotinamide cofactors for subsequent oxidation of DFF promoted by an ADH, thus implementing H2O2 internal recycling. The desired products FFCA and FDCA are obtained with yields of more than 95 %.