Application of Aqueous Biphasic Systems Extraction in Various Biomolecules Separation and Purification: Advancements Brought by Quaternary Systems

ABSTRACT Aqueous biphasic systems (ABS) extraction is a simple, selective, efficient and easy to scale-up technology that, over the years, has attracted a considerable attention from the researcher community as an alternative methodology in downstream processing of a wide variety of biomolecules. This review summarizes and discusses the fundamental features of ABS, as well as its advantages and disadvantages, as a separation and purification technology of biomolecules. Nevertheless, the focus of this review are quaternary ABS formed by the addition of neutral salts and ionic liquids to conventional ABS or those ABS composed by deep eutectic solvents and another phase forming compound. The advantages brought by quaternary ABS in terms of separation and purification of biomolecules, as well as the main issues governing the phase behavior of these systems, are discussed. With examples of application of quaternary ABS as an alternative extraction and purification methodology, it is shown that such ABS are a promising method to improve the effectiveness of biomolecules downstream processing, potentially providing a response to the increasing demand for high purity bioproduct. Furthermore, some of the discussed quaternary ABS have a great potential as a novel, sustainable and cost-effective purification platform for biomolecules downstream processing that can potentially simplify the whole ABS-based purification process due to no need for target bioproduct recovery or phase formers removal. Finally, perspectives of such quaternary ABS are made, and some future challenges pointed out.