Developments in membrane affinity chromatography for monoclonal antibody recovery

The great number of process development for monoclonal antibodies, presently in development stage, has emphasized the capability limits of the biotech industry. The recent improvements of fermentation technology, allow also to achieve high titers of monoclonal antibody in the supernatant production, and the present bottleneck for MABs’s production is associated to the downstream process required for the pure product recovery. Bead-based affinity chromatography with Protein A is widely used in the primary capture stage. Membrane affinity chromatography has not yet experienced extensive application due to the lower capacity of membrane supports compared to chromatographic beads, yet it has several advantages deserving serious attention. This work is focused on the purification of Immunoglobulin G (IgG) with affinity membranes. A new Protein A affinity membranes (Sartorius, Göettingen, Germany), as well as affinity membranes prepared with synthetic ligands have been characterized in detail in batch and dynamic experiments. The membranes have been analysed by using pure solutions of polyclonal IgG, to determine their binding capacity, as well as a cell supernatant containing monoclonal IgG, to investigate their selectivity and general behavior. The influence of process conditions like flow rate and feed concentration on adsorption and elution have been studied to obtain indications for the optimal process conditions. The affinity membrane purification process was also simulated with a mathematical model which was validated by using the experimental data obtained. The model can simulate adsorption, washing and elution steps by taking into account all the relevant transport phenomena.