Green bioprocesses in sponge-like ionic liquids

•Hydrophobic ILs are temperature switchable liquid/solid phases that behave as sponges (sponge-like ionic liquid, SLILs).•As liquid phase, SLILs are excellent reaction media for enzymatic synthesis of flavours and methyl oleate.•As solid phase, SLILs allow an easy product separation by simple centrifugation.

Ionic liquids (ILs) are a new class of liquid solvent, whose use has led to a green chemical revolution because of their unique array of physico-chemical properties, headed by their negligible vapour pressure and their exceptional ability to stabilize biocatalysts. Hydrophobic ILs based on cations with long alkyl side-chains, e.g. N,N,N,N-hexadecyltrimethylammonium bis(trifluoromethylsulfonyl)imide ([C16tma][NTf2]), are temperature switchable ionic liquid/solid phases that behave as sponge-like systems (sponge-like ionic liquid, SLILs). Based on this new property, SLILs have been used to develop straightforward and clean approaches for producing nearly pure synthetic compounds with added value (e.g. geranyl acetate, anisyl acetate, methyl oleate, etc.) in two steps: an enzymatic synthetic step as liquid phase, and then a product separation step involving simple centrifugation as a solid phase.

Graphical abstractHydrophobic ionic liquids based on cations with long alkyl side-chains are temperature switchable liquid/solid phases that behave as sponge-like systems (sponge-like ionic liquid, SLILs), being used to develop straightforward and clean biocatalytic approaches for producing nearly pure synthetic compounds.Figure optionsDownload full-size imageDownload high-quality image (194 K)Download as PowerPoint slide