Synthesis of 2,5-bis(hydroxymethyl)furan and furan-2,5-diylbis(methylene) diacetate from apple pomace waste via chemobiological catalysis

The direct valorization of real agricultural waste into high-value furan derivatives remains challenging because biomass deconstruction and selective downstream upgrading generally require chemically distinct catalytic environments. Here, a sequential chemobiological platform integrating deep eutectic solvent (DES) catalysis with recombinant whole-cell biocatalysis was developed for converting apple pomace (APP) into 5-hydroxymethylfurfural (HMF), 2,5-bis(hydroxymethyl)furan (BHMF), and furan-2,5-diylbis(methylene) diacetate (BAMF). Firstly, Betaine:Malonic acid (15 wt%) was employed to catalyze apple pomace (APP) into HMF (190 °C, 30 min), and the mass yield of HMF was 0.305 g/g APP. Recombinant Escherichia coli FucO-FDH cells co-expressing aldehyde reductase (FucO) and formate dehydrogenase (FDH) were used as whole-cell biocatalysts to catalyze the conversion of 300 mM HMF to BHMF (>99% yield). APP-derived HMF could be biocatalytically converted to BHMF in a mass yield of 0.31 g/g APP using E. coli FucO-FDH cell as a biocatalyst and sodium formate (3 mol of formate/mol of HMF) as a cosubstrate. Finally, recombinant E. coli ACT containing acyltransferase Ms AcT from Mycobacterium smegmatis was employed as the biocatalyst to transform 50 mM BHMF (obtained by reduction of commercial HMF and APP-derived HMF) into BAMF, with ethyl acetate serving as the acyl donor. Using biomass as the starting material, BAMF was prepared via a three-step process in chemobiological manner, extending biomass-derived platform chemicals to high-value derivatives.