(325b) Ionic Liquid-Solvent Mixtures: Enabling Cost-Effective Biomass Pretreatment

To date, only a handful of solvents are capable of solvating cellulose. Among the known solvent systems, ionic liquids (ILs) are exceptional cellulose solvents suggesting their use in a biomass pretreatment method in which the polysaccharides are dissolved and then regenerated prior to the subsequent hydrolysis step. This process greatly improves the enzymatic hydrolysis efficiency through dramatic changes in the structural properties of the regenerated biomass. Significant roadblocks exist, however, for the implementation of such a pretreatment process. Amongst these are the costly nature of the ILs, as well as practical processing limitations which exist due to the high IL viscosity. Although common solvents do not dissolve cellulose, we have discovered that relatively dilute solvent-IL mixtures readily dissolve significant amounts of cellulose. ILs have therefore been screened with a variety of molecular solvents for cellulose and corn stover dissolution. Through the addition of solvents, the solution properties can be fine-tuned, and a drastic reduction in the amount of IL is needed. Thus, this solvent-IL approach provides a viable route to a facile, cost-effective biomass pretreatment process.