Enhanced Biosynthesis of Furoic Acid via the Effective Pretreatment of Corncob into Furfural in the Biphasic Media

Aiming to develop an effective catalytic process for utilizing biomass, conversion of corncob into furfural was firstly performed using tin-loaded bentonite (Sn-BTN) as solid acid catalyst. Corncob was pretreated with Sn-BTN (3.5 wt%) for producing furfural at 53.3% yield in methyl isobutyl ketone-water (5:5, v:v; pH 1.0) biphasic media within 0.5 h at 170 °C. Furthermore, an efficient Sn-BTN recycling was achieved after 5 cycles of repeated use. Finally, furoic acid was obtained at 53.3% yield from corncob via sequential catalysis with solid acid Sn-BTN and Brevibacterium lutescens whole cells harboring furfural-oxidizing activity in methyl isobutyl ketone-H2O (5:5, v:v) media was developed under the relatively mild conditions. Clearly, this hybrid strategy for the synthesis of furoic acid from biomass was successfully developed via tandem catalysis of corncob with Tin-loaded bentonite and Brevibacterium lutescens whole-cell.