Analysis of Biomass Characteristics and Enzymatic Hydrolysis Efficiency by Continuous Pretreatment

In this study, biomass was pretreated by combining ball milling, homogenization, and hydrothermal pretreatments, and the efficiency of enzymatic hydrolysis was evaluated. After ball milling and homogenization pretreatments, no significant changes were observed in the chemical composition, and the crystallinity of the biomass decreased. However, the hemicellulose content decreased and the crystallinity increased after hydrothermal pretreatment. In particular, the hemicellulose decomposition of forest by-products was promoted during continuous pretreatments such as ball milling and hydrothermal pretreatment consequently, the xylan content in the pretreated biomass was 5.80%. However, the effect of single or continuous pretreatment on rice husk (RH) was insignificant in relation to that on the forest by-products. The structural changes in the pretreated biomass were investigated using Fourier transform infrared spectra, which revealed that the intensities of the hemicellulose-related peaks (1,745 and 1,245 cm^–1) obtained from the biomass pretreated via ball milling and hydrothermal pretreatments decreased. During enzymatic hydrolysis, the conversion rate of cellulose to glucose in the forest by-products pretreated via ball milling and hydrothermal pretreatments was the highest (84.49%). By contrast, this conversion rate in RH was low (22.72%), under the same conditions.