Efficient reduction of 5-hydroxymethylfurfural to 2, 5-bis (hydroxymethyl) furan by a fungal whole-cell biocatalyst

Biocatalytic reduction of biomass-derived 5-hydroxymethylfurfural (HMF) to 2,5-bis(hydroxymethyl)furan (BHMF) is considered as a sustainable method and has attracted great attention. In this work, a yeast-like fungus, Aureobasidium subglaciale F134 was discovered as a whole-cell biocatalyst for BHMF synthesis from selective reduction of HMF. Its resting cells exhibited high tolerance and excellent selectivity to HMF in a broad pH range. The catalytic capacity of the cells can be substantially improved by Zn²⁺ ion. Under the optimized reaction conditions, 180 mM HMF substrate was converted into BHMF with a yield of 82 % and 97 % selectivity in 9 h. In a fed-batch conversion, 430 mM of BHMF product was obtained within 15 h, giving a productivity of 3.7 g/l per hour. In addition, it was found that the cells could also selectively convert furfural to form furfuryl alcohol. Discovery of A. subglaciale F134 cells for BHMF synthesis broadens the biocatalyitc toolbox for sustainable production of bio-based chemicals and biofuels from biomass-derived HMF. In addition, the results provide more information regarding the identification of related enzymes in future work.