Comprehensive Utilization of Hemicellulose and Cellulose To Release Fermentable Sugars from Corncobs via Acid Hydrolysis and Fast Pyrolysis

Conversion of lignocellulose to sugars suitable for microbial fermentation is an outstanding obstacle in developing biorefinery. Both hemicellulose and cellulose fractions are polymers of sugars and thereby primary candidates for fermentable sugars production. In this study, the flexibility of an integrated biomass conversion process was offered. The hemicellulose of corncobs was utilized to release fermentable sugars by sulfuric acid hydrolysis first. The remaining solid residue from acid hydrolysis, containing a lot of cellulose, was further used to produce levoglucosan by fast pyrolysis. This process appeared to present several advantages: (i) Almost all of hemicellulose (99.7%) was hydrolyzed, and the yield of xylan was achieved 86.1%. (ii) The alkali and alkaline earth metals, which had negative catalytic influence on levoglucosan formation, were nearly and completely (93.7%) removed by acid pretreatment. (iii) A preferential degradation of hemicellulose and amorphous cellulose during acid hydrolysis...