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

Xue, Xin-Xia, Di, Jun-Hua, He, Yu-Cai, Wang, Bing-Qian, Ma, Cui-Luan
Applied biochemistry and biotechnology 2018 v.185 no.1 pp. 42-54
Escherichia coli, arabinose, catalysts, catalytic activity, cellulose, corn cobs, enzymatic hydrolysis, furfural, glucose, hemicellulose, oxalic acid, pH, synthesis, xylose, zinc
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 (2.5 g, dry weight) was pretreated with 0.5 wt% oxalic acid, the obtained corncob-derived xylose (19.8 g/L xylose) could be converted to furfural at 60.1% yield with solid acid catalyst SO₄²⁻/SnO₂-attapulgite (3.6 wt% catalyst loading) in the water–toluene (3:1, v/v) at 170 °C for 20 min. Moreover, the oxalic acid-pretreated corncob residue (1.152 g, dry weight) was enzymatically hydrolyzed to 0.902 g glucose and 0.202 g arabinose. Using the corncob-derived glucose (1.0 mM glucose/mM furfural) as cosubstrate, the furfural liquor (48.3 mM 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 (50 mM PEG-6000, 0.2 mM Zn²⁺, 0.1 g wet cells/mL, 30 °C, pH 6.5). After the bioreduction for 2 h, FAL was completely converted to FOL. The FOL yield was obtained at 0.11 g FOL/g corncob. Clearly, this one-pot synthesis strategy shows high potential application for the effective synthesis of FOL.