(355e) Understanding Ionic Liquid Pretreatment of Lignocellulosic Biomass by Hyperspectral Raman Imaging

Pretreatment of ligonocellulosic biomass is essential for breaking down the highly interwoven matrix of cellulose, lignin and hemicellulose, which facilitaties enzyme accessibility and adsorption to cellulose for efficient saccharification. Ionic liquids are a new class of non-volatile solvents exhibiting excellent solvating properties and have shown great promise for lignocellulosic biomass pretreatment with easy recovery of cellulose by rapid precipitation with anti-solvents.^1,2 Ionic liquids have been demonstrated to be very effective in cellulose solubilization in bulk, and have shown to swell cell walls perhaps by breaking inter and intra chain hydrogen bonding. However, to date, molecular level understanding of ionic liquid pretreatment on lignin and hemicellulose and its impact on different biomasses is lacking. The aim of this research is to develop a fundamental understanding of ionic liquid pretreatment by monitoring the compositional changes during the pretreatment process. Raman microscopy based on molecular vibrational spectroscopy is a label-free imaging technique capable of real-time and noninvasive examination of plant cell wall structures with chemical selectivity. In this research, we employed Raman hyperspectral imaging to study the impact of ionic liquid pretreatment on variety of biomasses to identify signatures for predicting deconstructionability and understand pretreatment dynamics by monitoring morphological and compositional evolution during deconstruction. Raman spectra of ground biomass and Raman images of plant cell wall ultra-structure upon pretreatment will be presented to gain a better understanding of ionic liquid pretreatment.

References (1) Dadi, A. P.; Varanasi, S.; Schall, C. A. Biotechnology and Bioengineering 2006, 95, 904-910. (2) Singh, S.; Vogel, K. P.; Simmons, B. A. Biotechnology and Bioengineering 2009, 104, 68-75.