Change of Structure of Corncob with Dilute Acid and Lime Pretreatment and a Potential Process for Xylose Co-Production of Cellulosic Ethanol

Degree of polymerization (DP) of cellulose is considered an important factor to effect on the conversion of Lignocellulose. The higher DP of cellulose, the more difficult conversion of lignocellulose is. In this study, corncobs were pretreated with dilute acid process for production of xylose, and then the residues were pretreated with lime. The enzymatic hydrolysis and the structures involved the composition, DP and crystallinity index of these two types of feedstock were determined. Comparison of structures resulted from these two pretreatment revealed that DP was not the crucial factor to determined efficiency of enzymatic hydrolysis. Lime pretreatment could improve the conversion of cellulose although the residues with lime pretreatment had higher DP and percentage of crystallized cellulose. Moreover, the results also confirmed lignin was not the key factors for enzymatic hydrolysis of lignocellulose because the residues with dilute acid pretreatment had the similar percentages of lignin to that with lime pretreatment. The crucial effect of lime pretreatment was to remove the inhibitor for cellulase and increase the percentages of cellulose. With obtained xylose, the residues with further lime pretreatment had expected efficient enzynmatic hydrolysis of cellulose. So this process could be a potential process for xylose co-production of cellulosic ethanol to decrease the cost of cellulosic ethanol.