(315b) Integrated Biorefineries: Isolation and Characterization of Lignin From Ionic Liquid Pretreated Biomass for the Production of Value Added Lignin by-Products

Plant (lignocellulosic) biomass is an abundant, inexpensive and sustainable source of organic carbon, for the production of renewable fuels and chemicals. However, many technical challenges exist in developing commercially viable processes for producing sugars from biomass that serve as precursors for fuel and chemical production. Pretreatment and enzymatic hydrolysis are critical steps, and most of the current pretreatment methods do not effectively disrupt the crystallinity of cellulose, which is a major barrier for efficient enzymatic hydrolysis. Ionic liquids (ILs) 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 like corn stover and poplar.

From an economic standpoint, it is of interest to facilitate the production of value added products from all components of the biomass, including lignin, given its interesting functionalities and properties owing to its complex aromatic nature. In integrated biorefineries, currently, residual lignin is primarily burnt for recovering heat. Suitable isolation of lignin from the ionic liquid pretreated biomass can help in producing value added lignin by-products like flame retardant materials, adhesives, high-strength fillers, surfactants, etc. In view of this, our study addresses: (1) the isolation of lignin from IL pretreated biomass subjected to enzymatic hydrolysis, using different enzyme mixtures, and (2) the characterization of recovered lignin compounds using thermal, chromatographic and spectroscopic methods, in order to assess its usability for further processing to produce value added products.