Effects of organosolv pretreatment and enzymatic hydrolysis on cellulose structure and crystallinity in Loblolly pine

Ethanol organosolv pretreatment was performed on Loblolly pine to enhance the efficiency of enzymatic hydrolysis of cellulose to glucose. Solid-state 13C NMR spectroscopy coupled with line shape analysis was used to determine the structure and crystallinity of cellulose isolated from pretreated and enzyme-hydrolyzed Loblolly pine. The results indicate reduced crystallinity of the cellulose following the organosolv pretreatment, which renders the substrate easily hydrolyzable by cellulase. The degree of crystallinity increases and the relative proportion of para-crystalline and amorphous cellulose decreases after enzymatic hydrolysis, indicating preferential hydrolysis of these regions by cellulase. The structural and compositional changes in this material resulting from the organosolv pretreatment and cellulase enzyme hydrolysis of the pretreated wood were studied with solid-state CP/MAS 13C NMR spectroscopy. NMR spectra of the solid material before and after the treatments show that hemicelluloses and lignin are degraded during the organosolv pretreatment.