The Benefits & Implementation of Precipitation with Professor Todd Przybycien, Carnegie Mellon University

Within the downstream bioprocessing world, chromatography is still by far the most common separation technique, but increasingly, novel strategies are being developed and implemented, especially within continuous systems.

As Professor Todd Przybycien, from the Carnegie Mellon University Departments of Chemical Engineering and Biomedical Engineering, explains: “Increasing secreted product titers have made bulk separations techniques such as precipitation and extraction increasingly attractive as alternatives to chromatographic operations.”

For Przybycien the benefits of precipitation in particular are numerous:

While precipitation doesn’t have the selectivity of chromatography, its selectivity does improve as target species concentrations increase and it can offer both process cost and time savings. In addition, the stability of proteins in native precipitate phases offers the opportunity to insert indefinite process hold steps and to consider integration with formulation operations.”

What is perhaps most promising about precipitation is how well it fits with one of the other great hopes for the future of the industry – continuous processing. Przybycien describes how “most intriguingly, precipitation is readily amenable to true continuous operation – in fact, continuous operation is the preferred mode of operation for precipitation based on operational consistency and scalability considerations.”

Przybycien adds that as with any novel process, there are a range of design considerations that need to be taken into account when implementing precipitation, including “selection of precipitants/mode of precipitation, solubility behaviour, precipitation kinetics, contacting conditions, filterability/washability, re-dissolution behaviour and re-dissolution kinetics.”

Todd Przybycien spoke on this topic at BioProcess International Europe 2016. See highlights from this year’s event and get all the latest updates at

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