HIGH EFFICIENT PRETREATMENT ON CORN STRAW AND SALIX PSAMMOPHILA AND ETHANOL FERMENTATION BY CONSOLIDATED BIOPROCESSING

Many mass-cultivated plants are not efficiently utilized to their potential because of their complex recalcitrant structures. In this study, three kinds of ionic liquid(IL), [BMIM]Cl, [EMIM]Ac and [BPy][HSO4], were used to pretreat corn straw and Salix psammophila to improve their degradation ratio, and then produce ethanol by consolidated bio-processing (CBP). FT-IR, SEM and XRD were used to analyze the change in performance of pre-treated corn straw and S. psammophila. The results showed that pretreated corn straw and S. psammophila were more amorphous, and the structure of lignocellulosic biomass had been disrupted. The degradation ratio of cellulose and hemicellulose in corn straw were increased by 24.3% and 10.8% respectively through [EMIM]Ac pretreatment. The degradation ratio of cellulose and hemicellulose of S. psammophila pretreated by [BMIM]Cl had increased by 28.4% and 15.4% respectively. The crystallinity indexes of native and [Emim]Ac-pretreated corn straw were 49.0% and 31.1% respectively. The crystallinity indexes of native and [Bmim]Cl-pre-treated S. psammophila were 37.4% and 22.3% respectively. Untreated and pretreated corn straw and S. psammophila were fermented to produce ethanol by CBP. The results showed the ethanol production from pretreated corn straw and S. psammophila were increased by 32% and 19% respectively. The recovery rates of [Emin]Ac, [Bmim]Cl and [Bhy][HSO4] reached 85%, 80% and 78% respectively. These results suggest that ionic liquid is an effective and lowcost pretreatment method. A higher ethanol titer was produced by Clostridium thermocellum comparing with untreated corn straw and S. psammophila with CBP.