Synthesis of 2,5-furandicarboxylic acid by a TEMPO/laccase system coupled with KT2440.

As a useful and renewable chemical building block from biomass, 2,5-furandicarboxylic acid (FDCA) has become an increasingly desirable platform chemical as a terephthalic acid replacement for polymerization. In this work, an efficient and highly selective biocatalytic approach for the synthesis of FDCA from 5-hydroxymethylfurfural (HMF) was successfully developed using a TEMPO/laccase system coupled with KT2440. TEMPO/laccase afforded the selective oxidation of the hydroxymethyl group of HMF to form 5-formyl-2-furancarboxylic acid as a major product, which was subsequently oxidized to FDCA by KT2440. Manipulating the reaction conditions resulted in a good conversion of HMF (100%) and an excellent selectivity of FDCA (100%) at substrate concentrations up to 150 mM within 50 h. The cascade catalytic process established in this work offers a promising approach for the green production of FDCA.