Novel process for the coproduction of xylo-oligosaccharides, fermentable sugars, and lignosulfonates from hardwood

Many biorefineries have not been commercialized due to poor economic returns from final products. In this work, a novel process has been developed to coproduce valuable sugars, xylo-oligosaccharides, and lignosulfonates from hardwood. The modified process includes a mild autohydrolysis pretreatment, which enables for the recovery of the xylo-oligosaccharides in auto-hydrolysate. Following enzymatic hydrolysis, the residue is sulfomethylated to produce lignosulfonates. Recycling the sulfomethylation residues increased both the glucan recovery and lignosulfonate production. The glucose recovery was increased from 81.7% to 87.9%. Steady state simulation using 100 g of hardwood produced 46.7 g sugars, 5.9 g xylo-oligosaccharides, and 25.7 g lignosulfonates, which were significantly higher than that produced from the no-recycling process with 39.1 g sugars, 5.9 g xylo-oligosaccharides, and 15.0 g lignosulfonates. The results indicate that this novel biorefinery process can improve the production of fermentable sugars and lignosulfonate from hardwood as compared to a conventional biorefinery process.