Steam explosion of mixed hardwood chips, rice hulls, corn stalks, and sugar cane bagasse

Abstract

Southern hardwood chips, rice hulls, corn stalks, and sugar cane bagasse were steam exploded. The hemicelluloses of all biomass materials were at least partially degraded. The hemicelluloses remaining were generally soluble in hot water. The cellulose content decreased only slightly. A portion of the lignin was soluble in hot aqueous alkali. However, up to half of the cellulose was also extracted by hot aqueous alkali. Acid hydrolysis of exploded hardwood chips, com stalks, and sugar cane bagasse showed no rate enhancement. Exploded rice hulls showed a hydrolysis rate increase of approximately 2-fold. Enzymatic hydrolysis rates showed a 10-fold increase for exploded hardwoods, sugar cane bagasse, and rice hulls. No enzymatic rate increase was observed for exploded corn stalks; untreated corn stalks hydrolyzed at a rate similar to that of filter paper. The results suggest that the steam explosion pretreatment may not be as promising as suggested by researchers who have exploded aspen