Integration of a perfusion reactor and continuous precipitation in an entirely membrane‐based process for antibody capture

Continuous precipitation coupled with continuous tangential flow filtration is a cost‐effective alternative for the capture of recombinant antibodies from crude cell culture supernatant. The removal of surge tanks between unit operations, by the adoption of tubular reactors, maintains a continuous harvest and mass flow of product with the advantage of a narrow residence time distribution (RTD). We developed a continuous process implementing two orthogonal precipitation methods, CaCl(2) precipitation for removal of host‐cell DNA and polyethylene glycol (PEG) for capturing the recombinant antibody, with no influence on the glycosylation profile. Our lab‐scale prototype consisting of two tubular reactors and two stages of tangential flow microfiltration was continuously operated for up to 8 days in a truly continuous fashion and without any product flow interruption, both as a stand‐alone capture and as an integrated perfusion‐capture. Furthermore, we explored the use of a negatively charged membrane adsorber for flow‐through anion exchange as first polishing step. We obtained a product recovery of approximately 80% and constant product quality, with more than two logarithmic reduction values (LRVs) for both host‐cell proteins and host‐cell DNA by the combination of the precipitation‐based capture and the first polishing step.