Simultaneously separation of xylo-oligosaccharide and lignosulfonate from wheat straw magnesium bisulfite pretreatment spent liquor using ion exchange resin

For wheat straw, an ideal bio-refinery process is that all three major components of biomass could be efficiently utilized to make high value chemicals, MBSP could directly convert the hemicelluloses and lignin into xylo-oligosaccharides and lignosulfonate. However, these value-added compounds still present in spent liquor and thus should be isolated as an individual product. In present work, a simple and efficient ion exchange process was developed for separating xylo-oligosaccharides and lignosulfonate simultaneously from spent liquor. D354 resin was selected for its high adsorption capacity of magnesium lignosulfonate and remarkable selectivity. 93.09% of XOS and 98.03% of lignosulfonate were recovered from the treated spent liquor in a fixed bed column with D354 resin. Overall, 1 L of MBSP spent liquor could coproduce 9.5 g XOS and 74 g lignosulfonate. These results offer an opportunity for complete and effective utilization of biomass by a novel integrated process coupling of MBSP and ion-exchange process.