Study of biomolecules partition coefficients on a novel continuous separator using polymer-salt aqueous two-phase systems

A novel experimental prototype device was evaluated for the continuous operation of an aqueous two-phase extraction protocol. As proof-of-concept, preliminary tests were performed using an organic blue and Gentian violet dyes, to demonstrate the capacity of the system for solute partitioning and continuous phase separation. Different experimental configurations were established by changing tubular separator length (3.0 and 5.0 m) and static mixer configurations (single Beads-filled tube, zig-zag, 3 Serial Beads-filled and tube Spiral/single Beads-filled tube). The use of different static mixer configurations ensured total organic dyes transfer from bottom to top phase with shorter equilibration time (1.0-4.0 min) than batch system. The turbulent regime created at the entrance of the device by the static mixer, contributed to an efficient mass transfer that resulted in improvement of product partition coefficient (Kp) previously obtained from batch systems, when bovine serum albumin (BSA) was used as a model protein. A complex protein extract, namely whey protein extract (WPI), characterized by the presence of two main proteins (alpha-lactalbumin and beta-lactoglobulin) with different phase affinities was successfully processed, resulting in differential protein partitioning with total recoveries up to 90% (top + bottom phase) and minimal protein precipitation at the interface. The obtained results suggested that the concentration of protein products in a defined phase could be feasible, by controlling the PEG-rich or salt-rich phase flow rates. These findings demonstrated the potential application of the proposed separator device for the continuous protein recovery using aqueous two-phase systems. (c) 2011 Elsevier B.V. All rights reserved.