INVESTIGATING THE EFFECTS OF IONIC LIQUID ON THE RECALITRANCE OF SOFTWOOD, HARDWOOD AND HERBACEOUS BIOENERGY FEEDSTOCKS

With the growing interest in utilizing renewable carbon from lignocellulosics biomass, ionic liquids show great promise as a host to biomass fractionation and utilization of each component (cellulose, hemicellulose, and lignin) in the production of value-added products. Improved understanding of the chemical changes occurring to the biomass when dissolved/activated in ionic liquid is key to achieving optimal utilization of lignocellulosic material. Past research 1 has shown that by decreasing the biomass crystallinity and cleaving acetyl groups from the hemicellulose via activation in EmimAce provides a less recalcitrant biomass that can be easily fractionated with an enzymatic approach. The effectiveness of this IL approach was studied in a variety of feedstocks to test its universal application for valuable chemicals and products. Principal component analysis (PCA) was performed to identify statistical differences in Fourier Transform Infrared (FTIR) spectra that correspond to chemical changes within the IL-activated biomass as compared to the control. The scores plot (Fig 4a) for Hybrid poplar reveals that dissolution at 72 hr lead to significant chemical changes within the biomass. Pine and switchgrass demonstrated similar separation. (data not shown). The deacetylation of the IL-activated biomass was confirmed by calculating the area under the band located at ~1740 cm -1 (relative to the unmodified biomass). The minimal mass loss could be related to the cleavage of these acetyl groups during the activation phase with minimal degradation to the cellulose, hemicellulose, or lignin components.