Purification of biomolecules combining ATPS and membrane chromatography

• Hybrid process: aqueous two phase extraction and membrane chromatography.
• Influence of PEG and phosphate concentration on membrane chromatography.
• Product recovery up to 99.9%.

Upstream processes for production of therapeutic proteins have been innovated and fermentation processes have been adopted for the use of recombinant microorganisms with high expression, but the downstream process is still the bottleneck in the biotechnological manufacturing process. A combined process consisting of aqueous two phase extraction (ATPE) and membrane chromatography is suggested to debottleneck downstream processing. ATPE has a large capacity, but the yield of the target product is from 74% to 97%. For this reason the product of ATPE waste stream is captured by membrane chromatography. In this work the binding capacity for the protein on protein A, ion exchange and hydrophobic exchange membrane chromatography was investigated experimentally with different concentration of polyethylene glycol (PEG), salt and protein. Protein A membrane was loaded with solutions resembling waste streams of ATPE for purifying IgG. For ion exchange and hydrophobic interaction membrane chromatography, the membrane was loaded with bovine serum albumin (BSA). PEG shows no significant effect on stability and capacity of membrane process. Even for small amount of BSA/IgG and high salt concentrations membrane adsorption is applicable. In this work it is demonstrated experimentally that a total product recovery of 99.9% for the purification of monoclonal antibody is possible.