P131: Scale up of a microbial harvest process

The development of harvest procedures for therapeutic protein products expressed as inclusion bodies (IBs) in E. coli has historically been challenging, due to the high solids content and the lack of an adequate bench scale-down model.  The goal of an E. coli harvest is the release of IBs from the cells and the concentration of the washed IB product intermediate for subsequent purification steps.  This is accomplished through mechanical disruption, followed by a series of washes and disk stack centrifugation steps to separate cell debris from the IBs. Centrifugation processes are generally scaled up using the Q/Σ method in order to maintain similar settling regimes across all scales.   However, this has been found to be a problematic methodology due to differing centrifuge geometries and mechanical constraints.  To overcome this challenge, a method based on the solids-handling capacities of the different centrifuges was used.  Although the scaled-up process flow rate ran as low as 70% of the flow rate predicted by Q/Σ, the process has been able to meet all acceptance criteria for yield and quality using the proscribed scale-up method.