Supercritical Fluid Delignification and Enzymatic Saccharification of Agave Bagasse

Biomass recalcitrance to saccharification is one of the major obstacles to cost-efficient production of fuels and chemicals from lignocelluloses. However, lignocellulosic biomass is recalcitrant to effective enzymatic hydrolysis because of its structural complexity, such as high degree of polymerization of cellulose, high crystallinity, presence of lignin and hemicelluloses, among others. A pretreatment operation is typically necessary to: (1) efficiently and economically break down the 3D structural network of cellulose, hemicellulose and lignin in the plant cell walls of lignocellulosic biomass, and (2) disrupt the tight hydrogen-bonded microcrystalline cellulose, both of which contribute to the recalcitrance of biomass to subsequent enzymatic saccharification. Lignin blocked cellulose accessibility to cellulose and decreases cellulose activity by competitively binding to hydrolytic enzymes. Delignification of agave bagasse using supercritical carbon dioxide with ethanol as co-solvent using different temperatures, pressures and solvent concentration was employed. Subsequently the biomass was hydrolyzed after pretreatment using cellulases combined with β–glucosidase and analyzed by X-ray diffraction, Fourier transform infrared spectroscopy, and wet chemistry methods.