Incorporating ultrafiltration into Protein A membrane chromatography as a strategy to reduce elution volume and buffer consumption

Background: Protein A chromatography is widely used for antibody purification. With conventional packed-bed columns, mass transfer within resin beads is diffusion-limited, entailing long residence time to achieve high binding capacities. Recently, several vendors have introduced Protein A membranes as alternatives to traditional Protein A resins/columns. These membranes feature open pore structures that facilitate the convective transport of protein molecules, enabling high binding capacities within significantly shorter residence time. The use of Protein A membranes can improve throughput, eliminate the need for column packing, and reduce cost. These advantages notwithstanding, Protein A membranes present certain drawbacks. A major limitation is their high dead volume-to-stationary phase ratio, which leads to larger elution volumes compared to their conventional counterparts. This results in significant eluate dilution and increased buffer consumption. Objective: In the current study, we aimed to demonstrate that ultrafiltration (UF), when used in combination with Protein A membrane chromatography, can address these limitations by allowing eluate concentration and buffer reuse. Methods: A laboratory model of UF integrated Protein A membrane was set up to test the feasibility and effectiveness of the proposed strategy. Results: Integrated UF effectively concentrated Protein A membrane eluate to a concentration comparable to that of Protein A column eluate. In addition, reuse of pH-adjusted UF filtrate as elution buffer reduces buffer consumption by 50%. Conclusion: UF integration is an effective solution for addressing the problem of increased elution volume and buffer consumption associated with Protein A membrane.