Chromatographic Techniques in the Downstream Processing of (Recombinant) Proteins

The purification of a (recombinant) protein produced by animal cell culture, the so-called downstream process (DSP), tends to be one of the most costly aspects of bioproduction. Chromatography is still the major tool on all levels of the DSP, from the first capture to the final polishing step. In this chapter we will first outline the commonly used methods and their setup, in particular ion exchange chromatography (IEX), hydrophobic interaction chromatography (HIC), affinity chromatography (AC), and gel filtration (gel permeation chromatography [GPC], size exclusion chromatography [SEC]), but also some lesser known alternatives. Then the rational design of a downstream process, which usually comprises three orthogonal Chromatographic steps, is discussed. Finally, process variants deviating from the usual batch-column/gradient elution approach will be presented, including expanded bed, displacement, and continuous annular chromatography, as well as affinity precipitation.