Protein partition on a derivative guar gum based aqueous two-phase system

Abstract

A new aqueous two-phase system based on a guar gum derivative, commercialized under the trade name of Solvitose Gum Ofa, and poly(ethylene glycol) is described. Its main difference from other polymer-polymer aqueous two-phase systems lies on the nature of Solvitose Gum Ofa - a commercially available galactomannam derivative is used. Previous works have characterized almost exclusively purified carbohydrates or their derivatives and have neglected the large amount of gums and carbohydrates there are usually used in paper, food or textile industries. Two-phase aqueous polymer systems based on such polymers may have the drawback of their degree of purification, which may interfere in the separation procedure. Influence of poly(ethylene glycol) molecular weight, ionic strength and affinity ligands on protein partition were studied. The increase in the partition coefficient of a model protein, Bovine Serum Albumin, due to the presence of ligands in one of the phases was three times smaller than the corresponding increase in a traditional system. This should not prevent the successful use of such polymers on aqueous two-phase polymer extraction. The cost of the studied system is six times smaller than Reppal PES-poly(ethylene glycol) systems and of the same order of other systems formed with crude polymers. Results indicate that this is a potentialy useful aqueous two-phase system for enzyme extraction.