Evaluation of Sugarcane Bagasse Pretreatment Process with Protic Ionic Liquids for Cellulosic Ethanol Production

Abstract

Although the pretreatment process of sugarcane bagasse for 2G ethanol production is thoroughly studied, there is no consensus on what would be the best for this type of biomass as there is usually a delicate balance of advantages ( Effective fractionation, low cost, environmentally friendly, etc.) and drawbacks (use of corrosive reagents, high cost, production of fermentation inhibitors, etc.). Although little explored, using protic ionic liquids (ILs) may be an alternative on the fractionation of lignin and on the modification of bagasse's ultrastructure. The vast majority of works in the literature use aprotic IL, whose production is far more expensive than the protic ones.In this work, the pretreatment process with protic IL will be evaluated, based on promising results obtained from our research group (patent application "Protic Ionic liquids in the pretreatment of lignocellulosic biomass," EA Rock, M. Aznar, AC Costa). The project will start up with a screening to investigate the best cation / anion combination that may extract lignin from bagasse with high efficiency in order to have minimal loss of solubilized carbohydrates (cellulose and hemicelluloses) in the ionic liquid. Then, the pretreatment process will be optimized using design of experiments. Temperature, solids concentration and duration of pre-treatment will be considered the factors and response variables will be lignin extraction efficiency, loss of carbohydrate and conversion yield of the enzymatic hydrolysis. The key steps in the development process will be the recycling of the ionic liquid, the recovery of lignin and the recovery of carbohydrates dissolved in LI (if there were solubilization). An overall mass balance for the process will be calculated to investigate the main causes of losses of the fractions of bagasse and of the ionic liquid. The study about the recovery of lignin after the pre-treatment and characterization of pretreated materials will be carried out at the University of Copenhagen, Denmark, under supervision of Professor Dr. Claus Felby.