Evaluating Self-buffering Ionic Liquids for Biotechnological Applications

Abstract

A new range of Good’s buffer ionic liquids (GB-ILs), displaying simultaneously the properties of ionic liquids and Good’s buffers, were synthesized by combination of Good’s buffers anions (MOPSO, BES, TAPSO and CAPSO) and tetrabutylammonium, tetrabutylphosphonium and cholinium cations via an acid-base neutralization reaction. The activity and stability of a lipolytic enzyme from Pseudomonas cepacia in aqueous solutions of these buffers were evaluated and the results show their advantage as media for enzymatic reactions when compared to conventional phosphate buffers. Moreover aqueous biphasic systems (ABS) composed by these GB-ILs and potassium citrate were investigated and shown to be highly effective and selective for the partitioning of the lipolytic enzyme into the GB-IL-rich phase. The results allow the development of an efficient and biocompatible process combining the self-buffering and enzyme-stabilizing properties of the GB-ILs in the reaction step, with the advantages of GB-ILs as extraction solvents in ABS.