The quality of the products of modern biotechnology often are limited by the effectiveness of the separation operations. The effectiveness of the separations technology is central to the biological activity, purity and safety of the products. Since biological materials must be concentrated and separated in their natural environment, special techniques must be developed for their processing and treatment. This program addresses one such need and focuses on a multiphase extraction system consisting of two aqueous (water) phases in which the proteins of interest are handled gently without denaturation. The research will explore how the protein can be segregated into one of the two phases and could be purified by settling under the influence of gravity. Thus no special machinery would be needed in the separation step.