EXTRACTION OF CONCANAVALIN-A WITH AFFINITY REVERSED MICELLAR SYSTEMS

An affinity reversed micellar system was used for extraction of concanavalin A (con A) with AOT and a biological detergent as the affinity cosurfactant. Six detergents with varying alkyl tail lengths and different head groups were compared for their extraction efficiency of con A. The effects of system parameters such as solution pH, cosurfactant concentration, and the presence of inhibitory saccharides on protein transfer were studied. For glucosides, protein transfer depends on the tail length of the cosurfactant, and the optimum length for maximum protein transfer is eight. A simple thermodynamic model for affinity partitioning of the protein between the two phases can fit the experimental results reasonably well. The estimated association constants for the protein-cosurfactant complex in the micellar phase are consistent with the literature values. For backward transfer of con A from a micellar phase with a stripping aqueous solution, 12.5% isopropyl alcohol addition to the aqueous phase can release the maximum amount of protein (88%). The reversed micelle still maintained its functional integrity after backward transfer, but loss of cosurfactant to the aqueous phase was significant, and reusability of the micellar phase was rather low. Using a more hydrophobic cosurfactant can only partially solve this problem, where spontaneous loss of cosurfactant to the phase interface during protein backward transfer still occurred.