Protein concentrator

A protein concentrator, comprising:

• means defining a reservoir for holding a protein solution;
• a cover assembly held within said reservoir;
• a semi-permeable membrane member having openings large enough to permit passage of water but having a molecule weight cut-off sufficient to prohibit the passage of at least some of the consituents of a protein solution, said membrane member being supported by said cover assembly and forming a tubular container positioned within the reservoir so that a protein solution held within the reservoir will contact the outer surface of the semi-permeable member and the inner surface of the semi-permeable member will not be exposed to the contents of the reservoir, the semi-permeable member being sealed to the container to prevent any portion of the protein solution from passing to the interior of the container without passing through the member;
• and
• a water soluble polymeric powder held within said membrane, said polymeric powder having a molecular size so that it will not pass through the semi-permeable membrane member, whereby when a protein solution is placed in the reservoir, the protein solution will contact the exterior surface of the semi-permeable membrane and a portion of the protein solution will pass through the membrane and dissolve a portion of the water soluble polymeric powder creating a concentration gradient across the membrane to increase the flux of the solution through the membrane and into the container thereby concentrating the protein solution in the reservoir.