Effect of Hemicelluloses Fractionated by Graded Ethanol Precipitation from Corn Stover on the Enzymatic Hydrolysis of Lignocellulosic Biomass

Abstract

The presence of hemicellulose inhibits the enzymatic hydrolysis of lignocellulosic biomass. The purpose of this study is to investigate the effect of different hemicellulose fractions on the enzymatic hydrolysis and the way to eliminate the inhibiting effect caused by hemicellulose. Four kinds of hemicelluloses, namely, H_XF, H₁₅, H₃₀, and H₆₀, were first extracted from corn stover by ethanol fractional precipitation. The structures of hemicellulose samples were analyzed using Fourier transform infrared spectroscopy, ¹H and ¹³C nuclear magnetic resonance, and high-performance ion chromatography. The results show that H₃₀ has the strongest inhibition on the enzymatic hydrolysis of Avicel and corn stover, presenting inhibition ratio of 13.35% and 9.98%, respectively. The inhibition ratios of other hemicelluloses in Avicel and corn stover are 8–12% and 5–9%, respectively. However, the inhibiting effect caused by H₃₀ is removed by adding hemicellulase, which even presents a 4.99% increase in the efficiency of enzymatic hydrolysis of corn stover. The corresponding glucose concentration reached 68.11 g/L. This research could help design effective processes to promote the enzymatic hydrolysis of lignocellulosic biomass.