Effect of [Emim]Ac pretreatment on the structure and enzymatic hydrolysis of sugarcane bagasse cellulose

Effect of ionic liquid pretreatment on enzymatic hydrolysis of cellulose was investigated in terms of the changes in the chemical and physical structure of the preparation. In this case, original cellulose isolated from sugarcane bagasse was subjected to ionic liquid ([Emim]Ac) dissolution at a mild temperature (90 °C) followed by regeneration in water and subsequently hydrolyzed by commercial cellulases. The original and regenerated cellulose were thoroughly characterized by XRD, FT-IR, CP/MAS 13C NMR, and SEM. It was found that the original cellulose experienced an increase in glucose content from 80.0–83.3% to 91.6–92.8%, a decrease in the degree of polymerization from 974–1039 to 511–521, a crystal transformation from cellulose I to cellulose II, as well as an increase of surface area during the pretreatment. The results suggested that pretreatment led to effective disruption of cellulose for subsequent enzyme hydrolysis as evidenced by a high glucose conversion yield of 95.2%.

► Original cellulose was pretreated with ionic liquid [Emim]Ac at 90 °C.
► Pretreatment increased glucose content and surface area of the cellulosic samples.
► The samples partially depolymerized and transformed from cellulose I to cellulose II.
► A high glucose conversion yield of 95.2% was achieved due to the structural changes.