Effective Utilization of Carbohydrate in Corncob to Synthesize Furfuralcohol by Chemical-Enzymatic Catalysis in Toluene-Water Media.

Abstract

In this study, carbohydrates (cellulose plus hemicellulose) in corncob were effectively converted furfuralcohol (FOL) via chemical-enzymatic catalysis in a one-pot manner. After corncob (2.5g, dry weight) was pretreated with 0.5wt% oxalic acid, the obtained corncob-derived xylose (19.8g/L xylose) could be converted to furfural at 60.1% yield with solid acid catalyst SO42-/SnO2-attapulgite (3.6wt% catalyst loading) in the water-toluene (3:1, v/v) at 170°C for 20min. Moreover, the oxalic acid-pretreated corncob residue (1.152g, dry weight) was enzymatically hydrolyzed to 0.902g glucose and 0.202g arabinose. Using the corncob-derived glucose (1.0mM glucose/mM furfural) as cosubstrate, the furfural liquor (48.3mM furfural) was successfully biotransformed to FOL by recombinant Escherichia coli CCZU-A13 cells harboring an NADH-dependent reductase (SsCR) in the water-toluene (4:1, v/v) under the optimum conditions (50mM PEG-6000, 0.2mM Zn2+, 0.1g wet cells/mL, 30°C, pH6.5). After the bioreduction for 2h, FAL was completely converted to FOL. The FOL yield was obtained at 0.11g FOL/g corncob. Clearly, this one-pot synthesis strategy shows high potential application for the effective synthesis of FOL.