2-06: Direct saccharification and fractionation of lignocellulosic biomass in concentrated salt solution at moderate temperature

Energy- and cost-effective saccharification remains a great challenge in bioconversion of lignocellulose to chemicals and fuels through carbohydrate platform. Current saccharification technologies for lignocellulose, such as concentrated acid process, diluted acid process, and enzymatic saccharification, are facing problems of equipment corrosion, acid recovery, requirement of energy- and cost-intensive pretreatment, and high cost of enzymes.

We report a novel process for direct saccharification and fractionation of lignocellulosic materials without any pretreatment. Under moderate conditions (100~160°C for 10~200 min) in acidic concentrated halide salt solution, polysaccharides (cellulose and hemicellulose) in lignocellulosic materials (such as corn stover, switchgrass, hardwood and softwood) were completely hydrolyzed into fermentable sugars with high selectivity. Only very small portion of the sugars were further degraded into furfural and hydroxymethylfurfural when temperature and acidity were high. Insoluble lignin could be easily separated from the sugar and salt solution through filtration or centrifugation. The used salt could be separated from the sugars and recovered through ion-exclusion chromatography.