Bioseparations in Aqueous Micellar Systems Based on Excluded-Volume Interactions

Protein partitioning based on micellar-induced excluded-volume interactions is studied for different aqueous nonionic micellar systems. In particular, protein partitioning in the traditional aqueous micellar two-phase system is compared with a system where a gel phase is combined with a micellar phase and with a membrane system with micelles at the feed side of the membrane. A two-phase system is created using cylindricallyshaped n-decyl tetra(ethylene oxide) (C10E4) micelles that are too large to diffuse into the gel-bead or across the membrane. Results are reported for the partition coefficient of single-component protein systems with myoglobin, ovalbumin, and BSA, and for binary protein mixtures. The individual protein partition coefficients in the mixtures follow the same protein concentration dependence as the partition coefficient obtained for the singlecomponent protein solutions.