Catalytic conversion of corncob to furfuryl alcohol in tandem reaction with tin-loaded sulfonated zeolite and NADPH-dependent reductase biocatalyst

Abstract In this study, tin-loaded sulfonated zeolite (Sn-zeolite) catalyst was synthesized for catalysis of raw corncob (75.0 g/L) to 103.0 mM furfural at 52.3% yield in water (pH 1.0) at 170 ℃. This corncob-derived furfural was subsequently biotransformed with recombinant E. coli CG-19 cells coexpressing NADPH-dependent reductase and glucose dehydrogenase at 35 ℃ by supplementary of glucose (1.5 mol glucose/mol furfural), sodium dodecyl sulfate (0.50 mM) and NADP+ (1.0 μmol NADP+/mmol furfural) in the aqueous catalytic media (pH 7.5). Both sodium dodecyl sulfate (0.50 mM) and Sn4+ (1.0 mM) could promote reductase activity by 1.4-folds. Within 3 h, furfural was wholly catalyzed into furfuryl alcohol, and its yield was 0.53 g furfuryl alcohol/g xylan in corncob. By combining chemical catalysis with Sn-zeolite and biocatalysis with CG-19 cells in one-pot, an effective and sustainable process was established for tandemly catalyzing renewable biomass into furfuryl alcohol under environmentally-friendly way.