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.…”

Biorrefinaria lignocelulósica empregando líquidos iônicos próticos para produção de etanol e lignina

“…The measurement of total OH was based on 31 P NMR, which is routinely used to quantify unlike OH groups in the structure of lignin. The integration data of various OH groups for all the lignins are summarized in the Mendeley Data 232 . Total OH values for the recovered lignins follow the order: [2He][Lac] > [Etid][Lac] > [Etid][Ac].…”

“…The bagasse obtained after pretreatment with the PILs [Etid][Ac], [Etid][Lac] and [2He][Lac] for 3 h at 140°C, 130°C and 160°C, respectively (experimental setup) 232 , were hydrolyzed by the enzymatic complex Cellic Ctec2 and the kinetic profiles are presented in Figura 6.1.4. The results of the conversion of cellulose and hemicellulose were not significantly different at the 90% confidence level by the Tukey test above 24 h, thus it is not necessary to perform the hydrolysis for 72h, which increases hydrolysis productivity.…”

“…Artigo "Effect of protic ionic liquids in sugarcane bagasse pretreatment for lignin valorization and ethanol production" 227 publicado na ACS Sustainable Chemistry & Engineering e o material suplementar abaixo se encontra disponível também no repositório Mendeley Data 232 .…”