Removal of inhibitory furan aldehydes in lignocellulosic hydrolysates via chitosan-chitin nanofiber hybrid hydrogel beads

To obtain fermentable sugars from lignocellulose, various inhibitors, especially furan aldehydes, are usually generated during the pretreatment process. These inhibitors are harmful to subsequent microbial growth and fermentation. In this study, a novel detoxification strategy was proposed to remove 5-hydroxymethylfurfural (HMF) and furfural while retaining glucose and xylose using self-prepared chitosan-chitin nanofiber hybrid hydrogel beads (C-CNBs). After C-CNBs treatment, the removal rates of HMF and furfural from sugarcane bagasse hydrolysates reached 63.1% and 68.4%, while the loss rates of glucose and xylose were only 6.3% and 8.2%, respectively. Two typical industrial strains grew well in monosaccharide-rich detoxified hydrolysates, with a specific growth rate at least 4.1 times that of undetoxified hydrolysates. Furthermore, adsorption mechanism analysis revealed that the Schiff base reaction and mesopore filling were involved in furan aldehyde adsorption. In total, C-CNBs provide an efficient and practical approach for the removal of furan aldehydes from lignocellulosic hydrolysates