Effect of ethanol organosolv pretreatment on enzymatic hydrolysis of Buddleja davidii stem biomass

Ethanol organosolv pretreatment was performed on Buddleja davidii to evaluate this bioresource as a potential feedstock for bioethanol production. B. davidii was pretreated and delignified, while 85% of the glucose content of the untreated material was retained in the pretreated solid fraction. The enzymatic hydrolysis showed that organosolv pretreatment produced solid substrates that were readily digestible by cellulases. Gel-permeation chromatography was used to determine the degree of polymerization (DP) of cellulose, and solid-state cross polarization/magic angle spinning ¹³C NMR experiments were conducted to study the changes in crystallinity and ultrastructure of cellulose. The results showed a decrease in DP along with an increase in the relative proportions of para-crystalline and amorphous cellulose and a decrease in cellulose I_a̧ and I_b̃. Removal of lignin and hemicellulose, reduction in DP, and decrease in the crystalline allomorphs (I_a̧ and I_b̃) increased the amenability of the biomass to enzymatic degradation.