Biomass deconstruction to sugars.

The production of biofuels from lignocellulosic biomass relies on the depolymerization of its polysaccharide content into fermentable sugars. Accomplishing this requires pretreatment of the biomass to reduce its size, and chemical or physical alteration of the biomass polymers to enhance the susceptibility of their glycosidic linkages to enzymatic or acid catalyzed cleavage. Well-studied approaches include dilute and concentrated acid pretreatment and catalysis, and the dissolution of biomass in organic solvents. These and recently developed approaches, such as solubilization in ionic liquids, are reviewed in terms of the chemical and physical changes occurring in biomass pretreatment. As pretreatment represents one of the major costs in converting biomass to fuels, the factors that contribute to pretreatments costs, and their impact on overall process economics, are described.