Selective. Fast. Scalable. Continuous. Simple. Inexpensive. Can the capture step be all these things for all (or at least many) recombinant protein processes, including monoclonal antibodies? Perhaps! We are exploring the use of continuous, integrated target precipitation-filtration for high titer recombinant protein capture. Precipitation becomes more efficient as titer increases (think Cohn plasma fractionation). And there is yield-purity synergy rather than trade-off. Continuous precipitation in tubular precipitators with narrow residence time distributions can produce consistent and scalable precipitate morphologies. Microfiltration can be integrated with precipitation to provide precipitate slurry dewatering and washing. Further, counter-current precipitate washing configurations can increase host cell protein removal, thereby boosting selectivity, and reduce buffer usage, . The key to successful operation is understanding and exploiting the interrelationships between precipitation conditions, precipitate yield/purity/morphology and filtration performance. We report on the use of a combined zinc (ZnCl2) and polyethylene glycol (PEG 3350) precipitant system to generate monoclonal antibody (mAb) precipitates from harvested cell culture fluids in a tubular reactor with internal static mixer to obtain nearly plug flow operation. The precipitates were dewatered and washed inline within integrated hollow fiber microfilters. The initial design and operation of the system was supported by high-throughput solubility measurements and precipitation kinetics data. The fouling behaviors of the precipitates within the hollow fiber microfilters were determined via critical flux experiments. We report on our initial yield, purity and fouling behavior findings with this continuous, integrated precipitation-filtration capture system. We further speculate on the use of this capture approach as a central feature of a simple, fully continuous (column chromatography-free) downstream process for high titer recombinant protein purification and prognosticate on process costs and suitability for low-resource environments.

Towards antibody capture via continuous integrated target precipitation-filtration

2019 Spring National Meeting

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