Improved Pretreatment of Biomass by Ionic Liquids Pretreatment
Pretreatment is a critical yet expensive stage in the biomass to biofuels pathway. However, pretreatment can reduce the overall biofuel production cost by facilitating conversion of the raw lignocellulosic biomass material into fermentable sugars and other valuable components. Pretreatment is thought to disrupt the lignin-carbohydrate complex in the cellulose microfibrils. Researchers at the DOE Joint BioEnergy Institute (JBEI) applied X-ray diffraction and small-angle neutron scattering to better understand ionic liquid pretreatment of these materials. The techniques were used to determine structural and surface changes in the biomass as a function of pretreatment conditions. Compared with other biomass samples studied, the ionic liquid pretreatment of switchgrass facilitated a more rapid expansion and conversion of the crystalline cellulose structure into a form more susceptible to enzymatic hydrolysis. The researchers also found that the degree to which lignin is intermixed within the cellulose microfibrils influences the required temperature and duration of an effective ionic liquid pretreatment.
Cheng, G., P. Varanasi, C. Li, H. Liu, Y. B. Melnichenko, B. A. Simmons, M. S. Kent, and S. Singh. 2011. “Transition of Cellulose Crystalline Structure and Surface Morphology of Biomass as a Function of Ionic Liquid Pretreatment, and Its Relation to Enzymatic Hydrolysis,” Biomacromolecules, dx.doi.org/10.1021/bm101240z.