Valorization of Wheat Bran for the Production of Xylo-Oligosaccharides and Monosaccharides Using Enzymatic Hydrolysis Coupled with Low-Intensity Acid Treatment

This study aimed to develop an effective technology for the conversion of wheat bran to xylooligosaccharides (XOSs) and monosaccharides. A glycoside hydrolysis (GH) 30_7 endoxylanase (<i>Pp</i>Xyn30B) and a GH43_36 α-l-arabinofuranosidase (<i>Pp</i>Abf43A) from <i>Penicillium parvum</i> 4-14 were subjected to recombinant expression and biochemical analyses. Wheat bran was fractionated into soluble arabinoxylans (WBAX 1 and 2) and insoluble residue (WBR) using alkaline hydrogen peroxide pretreatment and graded ethanol (50% and 75%) precipitation. The combination of <i>Pp</i>Xyn30B, <i>Pp</i>Abf43A, and <i>Ep</i>ABF62A (GH62) released approximately 40% of the XOSs (primarily xylobiose and xylotriose) and arabinose from WBAX1 and WBAX2. Integration of low-intensity acid treatment with the enzymatic hydrolysis significantly elevated the conversion ratios of XOSs (>75%) and arabinose (>95%). Moreover, the acid treatment facilitated the saccharification of insoluble arabinoxylan in WBR using an enzyme cocktail. These findings provide new insights into the xylanolytic enzymes and pathways involved in the valorization of cereal biomass.