Protein partitioning in aqueous two-phase systems formed by mixtures of polymers and cationic-anionic surfactants

A novel aqueous two - phase system (ATPS) can be formed by mixing a polymer and a cationic anionic surfactant. In this work we investigated the protei n partitioning in ATPS formed by mixing dodecyltriethylammonium bromide/sod ium dodecylsulfate and ethylene oxide (EO) - propylene oxide (PO) random co polymers (EO20PO80). Affinity ligands were attached to polymers and affinit y partitioning of proteins was investigated. A multi - step partitioning pr ocedure was developed by diluting the surfactant - enriched phase or by rai sing the temperature of polymer - enriched phase. After partitioning was co mpleted, the surfactants could be removed when the phases were further dilu ted, and EO - PO copolymers could be separated by raising the temperature a bove the cloud point of copolymer. The recycling of cationic - anionic surf actants and EO - PO copolymers is discussed.