New biomass processing technologies are currently explored for the production of energy from renewable sources. Lignocellulosic biomass is considered as a valuable source for chemicals and fuel production, but it is poorly soluble in conventional solvents. Increasing research on innovative technologies for the exploitation of natural biopolymer resources is carried out. Ionic liquids (ILs) were successfully applied as alternative solvent in biomass pretreatment and hydrolysis of cellulose, but they often show limitations concerning costs, recyclability and/or biodegradability. Low Transition Temperature Mixtures (LTTMs) belong to a new family of solvents that could overcome these limitations. By changing (the molar ratio of) the counterparts of LTTMs, the physiochemical properties and solvent performances can be tuned. LTTMs were screened for the solubility of lignin, cellulose and starch and showed to be able to selectively extract lignin from lignocellulosic biomass. Encouraged by the results of this first screening, the research on suitable LTTMs for lignocellulosic biomass processing was expanded. As shown in figure 1, the solubility of cellulose increases with the amino acid (proline) content. Except for malic acid, none of the previously screened hydrogen bond donors could form a LTTM with an amino acid content of more than 60 mol%. The current research focuses on screening the countless unexplored combinations of carboxylic acids and amino acids for LTTM formation and biopolymer solubility, pursuing the optimal natural solvent for lignocellulosic biomass processing.
|Publication status||Published - 2013|