NSF Award
8860125
The proposed work is directed at the development of a novel and highly selective membrane for the continuous purification of valuable proteins such as interferon from complex and dilute mixtures. Production of proteins requires three main steps: fermentation or cell culture, isolation, and purification. Fermentation and cell-culture processes have undergone much development; isolation and purification are now the weakest parts of the overall scheme. The goal of the Phase I program is to establish the feasibility of employing "affinity membranes" to purify hydrophobic proteins. The affinity membrane consists of a microporous membrane in which the pores have been filled with an affinity ligand that selectively binds the desired protein. Transport of proteins across the filled pores occurs by dissolution into and diffusion through the pores. Alpha-chymotrypsin is an inexpensive protein that will be used as a model compound in Phase I; it is a good substitute for proteins like interferon, which are of very high added value. Preliminary calculations indicate that the membrane-based purification of interferon can be performed by the membranes to be developed in the project at a cost as low as $0.46/million units of interferon--less than 1 percent of the current selling price. The proposed work is directed at the development of a novel and highly selective membrane for the continuous purification of valuable proteins such as interferon from complex and dilute mixtures. Production of proteins requires three main steps: fermentation or cell culture, isolation, and purification. Fermentation and cell-culture processes have undergone much development; isolation and purification are now the weakest parts of the overall scheme. The goal of the Phase I program is to establish the feasibility of employing "affinity membranes" to purify hydrophobic proteins. The affinity membrane consists of a membrane in which the microscopic pores, which normally allow water to channel through the membrane, have been filled with an immobilized solution of molecules which selectively bind the desired protein. Proteins will be transported across the filled pores as they dissolve into the immobilized solution inside the pore and diffuse through to the other side, where they will be collected in an appropriately buffered water solution. Alpha-chymotrypsin is an inexpensive protein that will be used as a model compound in Phase I; it is a good substitute for proteins like interferon, which are of very high added value. Preliminary calculations indicate that the membrane-based purification of interferon can be performed by the membranes to be developed in the project at a cost as low as $0.46/million units of interferon--less than 1 percent of the current selling price. In contrast, a general rule of thumb in conventional separations of proteins produced by fermentation or cell culture is that the separation costs account for 90 percent of the final cost of the product.
