An efficient chemoenzymatic strategy for valorisation of corncob to furfuryl alcohol in CA:Betaine-water

Abstract

Biobased chemical furfuryl alcohol is an important furfural-upgrading compound, which is mainly used to prepare fruit acids, resins, additives, polymers, fibers, and rocket fuels. In this study, one sustainable way for valorisation of biomass into furfuryl alcohol was developed via chemoenzymatic conversion in one-pot manner. Deep eutectic solvent (DES) CA:Betaine was prepared by mixing betaine and citric acid (CA). Using CA:Betaine (10 wt%) as catalyst and reaction medium, the carbohydrates (glucan plus xylan) in corncob (60 g/L) were firstly catalyzed to produce 74.6 mM furfural, 96.5 mM formic acid and 40.3 mM glucose at 170 °C for 30 min in CA:Betaine-water (10:90, wt:wt). Furthermore, co-expression of formate dehydrogenase (FDH) and NADPH-dependent aldehyde reductase (SsCR) from Sporidiobolus salmonicolor in one E. coli was a good strategy for the efficient biosynthesis of furfuryl alcohol. Within 2 h, E. coli SF21 efficiently converted corncob-derived furfural (74.6 mM) to furfuryl alcohol in a yield of 95.8 % by using corncob-derived formate and glucose as co-substrates. The furfuryl alcohol productivity was obtained at 0.117 g furfuryl alcohol/g corncob (0.343 g furfuryl alcohol/g xylan). Overall, this study provided a novel chemoenzymatic strategy for catalysis of biomass into furfuryl alcohol in CA:Betaine-water.