3-112: Pretreatment of Lignocellulosic Biomass using Ionic Liquids for Production of Ethanol

Declining nonrenewable petroleum resources combined with political and environmental concerns over fossil fuels have necessitated the search for alternate energy sources. In this respect, plant (lignocellulosic) biomass is an abundant, inexpensive and sustainable source of organic carbon, and the production of ethanol as a renewable fuel from lignocellulosic biomass seems to be a promising transportation fuel. However, many technical challenges exist in developing commercially viable processes. Pretreatment and enzymatic hydrolysis are critical steps in the production of fuels from biomass and most of the current pretreatment methods do not effectively disrupt the biomass structure, especially the crystallinity of cellulose, which is a major barrier for efficient enzymatic hydrolysis. Ionic liquids being non volatile, non-flammable, recyclable and designer friendly, are gaining wide recognition as green solvents, and their unique solvating properties make them ideal for pretreating lignocellulosic substrates. Enhanced enzymatic hydrolysis yields of glucan to glucose and xylan to xylose are observed for ionic liquid pretreated ligocellulosic substrates like sugarcane bagasse, corn stover and poplar. However, economic viability materializes only when the process solvent is completely recovered and recycled. This work addresses the enhancement of enzymatic hydrolysis of lignocellulosic biomass using suitable ionic liquids and the recovery and recycle of ionic liquids by different approaches.