| Recently ionic liquids have been under investigation for their use in pretreatment of biomass material, and a specific group of cholinium ami no acid ionic liquids ([Ch][AA]) were studied for their ability to selectively extract lignin from lignocellulose. From the previous studies,[Ch][Lys] and [Ch][Phe] were chosen for further study.[Ch][Lys] was the strongest candidate for overall sugar yield but lacking xylose utilization, and [Ch][Phe] showed the best xylose utilization but had a low overall yield. Using different combinations of the two ionic liquids, it was possible to tailor the lignocellulose pretreatment for the best balance between xylose utilization and lignin removal to achieve a higher overall sugar yield after enzymatic hydrolysis.The conditions tested were based on previous studies, the conditions for best xylose utilization and best overall sugar yield were combined with different ratios of the two ionic liquids. It was found that using between20%and40%[Ch][Lys] at90℃for8hours granted the best results. It was possible to retain80,1%cellulose and xylan while removing42,4%lignin using20%[Ch][Lys]. Using40%[Ch][Lys] resulted in a retention of76,3%cellulose and xylan and removed57,0%lignin.Regeneration was attempted, while it was possible to reuse the ionic liquid the residues share of cellulose and xylan would fall between batch one and two. However biomass recovery was the same and after second batch the composition of the residue was stable. |
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