Sunday, May 3, 2009
3-54
Evaluation of lignocellulose dissolution in ionic liquids as a pretreatment strategy for ethanol and lignin production
Sergios Karatzos, William Doherty, and Les Edye. Queensland University of Technology, 2 George St, Brisbane, Australia
Ionic Liquids (ILs) are liquid salts with extraordinary dissolution behaviour and physical properties. For example, 1-n-butyl-3-methylimidazolium chloride (bmimCl) is able to completely dissolve lignocellulosics. The components of lignocellulosics can be recovered and partially fractionated by the addition of antisolvents. It is known that the cellulosic fractions recovered from bmimCl are more amenable to enzymatic hydrolysis than cellulosic fractions recovered from other pretreatment processes. The utility of this dissolution strategy as a biomass pretreatment for enzymatic saccharification and bioethanol production is evaluated by determining the kinetics of dissolution of sugarcane bagasse in imidazolium salts over a range of temperatures and biomass loadings; assessing the choice of antisolvent; quantifying the recovery of the IL and biomass fractions including lignin; and comparing the ease of enzymatic saccharification of the cellulosic products from the ILs with that of dilute acid pretreatment. All cellulosic products recovered from IL dissolution have enhanced saccharification kinetics. However, the biomass loading and choice of antisolvent have a significant impact on the IL recovery and consequently on the economic feasibility of IL-based pretreatment processes.