One-Pot Chemobiocatalytic Production of 2,5-Bis(hydroxymethyl)furan and Its Diester from Biomass in Aqueous Media

Direct valorization of biomass into value-added chemicals is attractive yet challenging. Herein, we report a one-pot synthesis of 2,5-bis(hydroxymethyl)furan (BHMF) and its diacetate from inexpensive fructose and sugar syrup in the aqueous phase via sequential chemical dehydration, biocatalytic reduction, and esterification. A robust alcohol dehydrogenase from Escherichia coli (EcYjgB) was identified for HMF reduction, with high catalytic efficiencies toward 5-hydroxymethylfurfural (HMF) (kcat/Km, 1300 s–1 mM–1) as well as NADPH (9700 s–1 mM–1). Recombinant E. coli harboring EcYjgB (E. coli_EcYjgB) showed high tolerance toward highly toxic and strongly inhibitory biobased furans, enabling smooth reduction of 1 M HMF and 0.5 M furfural. Its practicality was demonstrated by gram-scale synthesis of BHMF with a 79% isolated yield at approximately 126 g/L substrate loading. Biocatalytic process intensification was realized by improving cell membrane permeability using ethyl acetate, providing up to 15 g/L h BHMF productivity. A concurrent biocatalytic cascade for producing BHMF diacetate from HMF was constructed by combining E. coli_EcYjgB and Mycobacterium smegmatis acyltransferase (MsAcT) variant N94A, affording the desired product with a 93% yield in 1 h. Starting from crude HMF obtained via chemical dehydration and organic solvent evaporation, BHMF and its diacetate were produced with >99 and 88% yields, respectively. Finally, direct synthesis of these furan-based products from sugars was performed by chemobiocatalysis, without isolation of any intermediates, resulting in yields of up to 59% (relative to sugar). This work may pave the way for scalable production of furan-based chemicals from inexpensive renewable biomass.