Enhancing economic and environmental friendliness of xylonic acid bioproduction from corncob hydrolysate by the combined recycling-technology of detoxifying-resin and catalyzing-cell

Abstract

The bioproduction of xylonic acid (XA) from acidic lignocellulosic hydrolysate presents a potential booming research area, that XA serves as an important building block of biomass-based chemicals for biomass valorization. However, the existence of inhibiting compounds such as acetic acid in hydrolysate greatly influences bacterial cell metabolism and catalysis, as well as the following electrodialysis separation for XA purification. Therefore, the removal of inhibitors including acetic acid is an essential issue in the industrial bioproduction of XA. In this study, five polymer resins were evaluated on their ability to remove acetic acid and other inhibitors from acidic hydrolysate of corncob (AHC). By comparison, anion exchange resin 335 performed the best on the removal of acetic acid in the model solution and AHC at 100 % and 80 %, respectively, while the sugar loss was also confined within 10 %. Finally, 208.6 g XA was obtained with a productivity of 5.8 g/L/h by 6 rounds of cell-recycling bioconversion. Moreover, recycled resin kept at least 80% toxic removal efficiency after 4 renewed rounds with hot water washing. The combined recycling-technology of detoxifying-resin and catalyzing-cell greatly facilitate economic and environmental bioproduction of XA from lignocellulosic biomass.