Methods
Process overview
The purification process for this study included an automated and
integrated dual-column chromatography step (DCC) (Angarita, 2015),
leading into a continuous virus inactivation (VI) step and a final
flow-through polishing AEX step. Upstream and downstream of the DCC step
were 10L glass vessels to accommodate purification of 50L of cell
culture material per day. The process flow path, the connections between
each unit operation in the process and the automation to control and
acquire the data from all unit operations in parallel, were executed
with four 500mL flow kits and the Pilot PAK system from PAK BioSolutions
(Virginia, US). The flow path of the process and the PAK flow kits are
shown in Figure 1 and Figure 2, respectively. The 50L per day of
harvested material was combined from several different perfusion
bioreactors that had run prior to this study. The bags were chosen and
connected in order to simulate the titer profile of a typical perfusion
bioreactor process.