An integrated acetic acid-catalyzed hydrothermal-pretreatment (AAP) and rapid ball-milling for producing high-yield of xylo-oligosaccharides, fermentable glucose and lignin from poplar wood

An integrated pretreatment that realizing effective fractionation and targeted valorization can guarantee the implementability to future biorefinery scenario. In the present study, a stepwise approach using acetic acid-catalyzed hydrothermal pretreatment (AAP) and rapid ball-milling process was successfully developed for producing high-yield of xylo-oligosaccharides (XOS), fermentable glucose and native lignin from poplar wood. It was found that the AAP removed the most hemicelluloses, releasing the highest yield (36.16%) of XOS at 160 °C for 1 h. Subsequent rapid ball-milling pretreatment for 10 min led to a remarkable increase in the saccharification efficiency from 40.68% to 91.35%. Meanwhile, the residual lignin fractions exhibited abundant β-O-4 linkages, which are beneficial to catalytic hydrogenolysis of these lignin fractions into the aromatic chemicals. Considering the integrated process could effectively produce XOS, fermentable glucose, and the residual lignin with well-preserved structures, the proposed process is a promising and efficient deconstruction strategy in current biorefinery scenario.