Ionic liquids in the life sciences: Are ionic liquids useful for the manipulation of biomolecules

Biocatalysis in non-aqueous media has become increasingly important over the past decade as the demand for enantiopure and other high-value added products has dramatically risen. The use of ionic liquids (ILs) as non-traditional, non-aqueous solvents for biocatalytic reactions has recently become an area of interest as preliminary results have shown both increased enantioselectivities and reaction rates. These results coupled with the potential for new chemistries in these "green" solvents have served to further propel this field. However, fundamental studies probing protein stability as a result of an IL environment have been lacking. In this work, the effects of various ILs on protein stability and methods by which improved stability may be ascertained were investigated.; This work outlines the benefit of medium engineering on protein stability. Novel ILs containing hydroxyl functionality have been prepared using a clean, atom-efficient synthesis resulting in a more favorable microenvironment for the biocatalyst compared to traditional alkylimidazolium ILs. Application of these ILs to biocatalytic processes appears to be promising as they have been shown to provide effective stabilization of model proteins.; The use of ILs in well-established methods to achieve increased enzymatic activity, such as enzyme immobilization, has also been investigated. In doing so, a new method has been developed for introducing active biocatalysts into cellulosic matrices using a cellulose-in-IL dissolution and regeneration process. Additionally, cellulose composite materials have been prepared providing primary amine surface functionality enabling direct, one-step bioconjugation.; Lastly, the denaturation of Trichoderma reesei cellulase in 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) has been shown to result in its inability to refold into its active form. However, covalent modification of the cellulase with a polyethylene glycol (PEG) polymer and modification of the reaction solvent through exchange of anionic components has been shown to drastically increase enzymatic activity.; Fundamental principles of protein stabilization in non-aqueous solvents have been applied to IL systems to achieve sustained or increased enzymatic activity and stability. The use of ILs as solvents for biocatalytic processes holds significant promise demonstrating the coupling of increased enzymatic activity afforded by its non-aqueous nature with the reduction in the use of volatile organic solvents.