(131d) Optimization and Scale-up of Microfiltration TFF for Reliable Clarification Processes
AIChE Annual Meeting
2016
2016 AIChE Annual Meeting
Separations Division
AIChE-SCEJ Joint Session: Bioseparations and Bionanotechnology
Monday, November 14, 2016 - 1:30pm to 1:50pm
One of the most challenging steps in the manufacture of microbially produced therapeutics is the clarification of feed solutions containing solubilized inclusion bodies. In such applications the recovery and purity of the target protein is often limited. The high percentage of impurities results into low depth filter capacities applying the normal flow filtration (NFF) and insufficient separation efficiency in addition to the scale-up limits of the centrifugation. Tangential flow filtration (TFF) with a microfiltration membrane has been considered in such processes. Importantly, the control of permeate flow rate is essential to achieve filtration success criteria and limit fouling.
This study highlights the successes of a permeate-controlled TFF microfiltration process at various scales with different feed streams. The laboratory TFF system with a membrane area of 0.1 m2 was used for the initial evaluation. A pump controlled the permeate flux ensuring a stable and successful process operation. By using the model feed (BSA containing Whey feed stream), the protein sieving was investigated. The process simulation has confirmed the cake-mass resistance profile and protein sieving prediction. For the clarification process of solubilized IBs from Escherichia coli, the permeate-controlled TFF set-up was compared to the NFF process in regards to separation efficiency. Although the TFF membrane used has a smaller nominal pore size than the used depth filters, a Pellicon 1000 kDa PES membrane in V-screen cassette provided higher retention of impurities. The resistance curves were analyzed applying the cake-lift model for TFF and cake model for NFF. The overall fittings suggests that the advantage of the permeate-controlled TFF might be due to the control of the membrane pressure increase which results in low membrane fouling, effective separation and high protein sieving. The scale-up to the Phase I GMP runs demonstrated the robustness of this technology and justifiably used in a clarification process.
This study highlights the successes of a permeate-controlled TFF microfiltration process at various scales with different feed streams. The laboratory TFF system with a membrane area of 0.1 m2 was used for the initial evaluation. A pump controlled the permeate flux ensuring a stable and successful process operation. By using the model feed (BSA containing Whey feed stream), the protein sieving was investigated. The process simulation has confirmed the cake-mass resistance profile and protein sieving prediction. For the clarification process of solubilized IBs from Escherichia coli, the permeate-controlled TFF set-up was compared to the NFF process in regards to separation efficiency. Although the TFF membrane used has a smaller nominal pore size than the used depth filters, a Pellicon 1000 kDa PES membrane in V-screen cassette provided higher retention of impurities. The resistance curves were analyzed applying the cake-lift model for TFF and cake model for NFF. The overall fittings suggests that the advantage of the permeate-controlled TFF might be due to the control of the membrane pressure increase which results in low membrane fouling, effective separation and high protein sieving. The scale-up to the Phase I GMP runs demonstrated the robustness of this technology and justifiably used in a clarification process.