Effect of Protic Ionic Liquids in Sugar Cane Bagasse Pretreatment for Lignin Valorization and Ethanol Production

Abstract

Ionic liquids have been called designer solvents because it is possible to fine-tune their properties from a huge range of possible combinations of cations and anions. In this work, we evaluate the potential of protic ionic liquids (PILs) in the fractionation of sugar cane bagasse in a biorefinery context. The PILs were designed to selectively solubilize lignin and leave a polysaccharides solid fraction. The carbohydrate fraction was further hydrolyzed to obtain pentose and hexose sugars, which were fermented using a pentose-consuming yeast. The results have shown that, differently from pretreatments that solubilize hemicelluloses, pentoses could be fermented together with hexoses without a prior detoxification step with high yield and productivity. The lignin recovered was characterized by 2D HSQC NMR, 31 P NMR, and GPC, showing that the design of the PIL influences lignin characteristics, but pretreatment temperature and time do not. The lignins obtained are sulfur-free, and the richness of their functional groups makes them attractive for conversion into a diversity of value-added products, which can make a biorefinery based on the proposed process viable.

Efficient Lignin Fractionation from Scots Pine (Pinus sylvestris) Using Ammonium-Based Protic Ionic Liquid: Process Optimization and Characterization of Recovered Lignin

“…The peak at 2930 cm −1 indicates the C–H stretching in methyl and methylene groups. The detection of a new peak at 1688 cm −1 represents the carbonyl (C=O) group, which confirms the activation of PWB lignin during the [N11H(2OH)][LAC] pretreatment [ 27 ]. Further, the stretches of CO and CC of aromatic moieties of lignin were observed at 1594 cm −1 and 1515 cm −1 , respectively [ 28 ].…”

Organo‐Catalytic Approach for Biscoumarin Synthesis via a Biomass‐Derived Sustainable Strategy

“…[7] Recently ionic liquids (IL) derived from biomass have found a great interest. These have shown versatile applications such as biomass conversion, [8] toxic metal sequestration, [9] organic synthesis, [10,11] CO 2 capturing [12,13] and many more. These have been classified into many classes based on the type of transformation such as chiral ILs, task specific ILs, basic ILs etc.…”