Sulfonated Vermiculite-Mediated Catalysis of Reed (Phragmites communis) into Furfural for Enhancing the Biosynthesis of 2-Furoic Acid with a Dehydrogenase Biocatalyst in a One-Pot Manner

2-Furoic acid (FA), an upgrading product of furfural via oxidation, has been widely used in flavor, fragrance, polymer, agrochemical, and pharmaceutical industries, which can be manufactured from biomass-derived furfural. It is known that reed (Phragmites communis) is renewable, abundant, and inexpensive lignocellulosic biomass. In this study, FA was synthesized from reeds via the chemoenzymatic route. First, sulfonated tin-based vermiculite (Sn-vermiculite) was prepared as a solid acid catalyst to transform reeds into furfural, and 4.0 wt % loading of Sn-vermiculite gave furfural (55.0 mM) in a yield of 38.4% from NaOH-soaked reeds (AP-reeds) at 170 degrees C within 20 min. XRD, FT-IR, and SEM indicated that pretreated reeds had roughness and complexity of a wall surface because of severe pretreatments. In Sn-vermiculite-treated AP-reeds, over 98% of xylan in untreated reeds was removed. Furfural was obtained at 0.231 g furfural/g of xylan in AP-reeds. Furthermore, Escherichia coli HMFOMUT whole cells harboring dehydrogenase were used for biotransforming furfural to FA at 30 degrees C and pH 6.5. Finally, AP-reed-derived furfural was entirely into FA with 0.269 g FA/g of xylan in AP-reeds by E. coli HMFOMUT whole cells after 30 h. Significantly, this hybrid strategy was successfully established for transforming reeds to FA by sequential catalysis via the Sn-vermiculite catalyst and dehydrogenase biocatalyst.