Aqueous biphasic systems composed of a water-stable ionic liquid + carbohydrates and their applications

Abstract

A water-stable ionic liquid, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, [C₄mim][CF₃SO₃], is herein proposed to be used in the formation of aqueous biphasic systems (ABS) with a large range of mono- and disaccharides, as well as polyols. Binodal curves, tie-lines, and densities and viscosities of the co-existing aqueous phases, were determined for each ternary system. The proposed systems are low-viscous offering enhanced features over conventional polymer-based ABS. In addition, the partitioning of model biomolecules, such as L-tryptophan, caffeine, and β-carotene, was further investigated to ascertain the applicability of such ABS. These systems are particularly interesting in the recovery of bioactive products from natural sources, while the availability of carbon-based sources to cells constitutes a major advantage in separations from fermentative media. Moreover, the use of carbohydrates in ionic-liquid-based ABS constitutes a step forward along the biorefinery concept envisaging sustainable conversions of biomass into a broad spectrum of bio-based products.