Assessment of a disc stack centrifuge for use in mammalian cell separation

Abstract

A prototype disc stack centrifuge was tested for the separation of mammalian cell cultures from 80- and 2000-L fermentations. The clarification capacity for mammalian cells was excellent, but some smaller particles remained in the supernatant and reduced its usefulness for downstream processing. In order to identify the source of such particle formation, several parameters were assessed and minimum particle size for separation was calculated. An analysis of particle distribution was performed. Temperature and pressure effects inside the centrifuge bowl were measured. Some modifications of mechanical engineering can be suggested for the improvement of the use of standard disc stack centrifuges for mammalian cells. (c) 1995 John Wiley & Sons, Inc.

PDADMAC flocculation of Chinese hamster ovary cells: Enabling a centrifuge-less harvest process for monoclonal antibodies

“…To enable processing using a typical continuous centrifuge, the feed must contain solids at or below 10-12%. 2 Feed solid levels above this require a dilution. For MF harvesting, product recovery is a function of the mAb sieving and the number of diafiltration (DF) volumes of the CCF (V CCF ).…”

“…Optimal flocculation performance is the combination of the shortest flocculent settling period and with an optical clarity of less than 40 NTU Normalized Flocculent Dosing To: removal of these sub-micron particles improves membrane filtration throughput at least 6-fold. 2,21 Flocculation of the sheared cell broth, which had approximately 10 times the amount of sub-micron particles as the nonsheared cell broth, required a 2-fold increase in the PDADMAC dose to achieve a similar settled flocculent volume in 2 hours compared to flocculation of non-sheared cell broth (Fig. 6).…”

“…2 Of the two bulk solid separation methods, centrifugation has become the primary recovery method due to the advent of low shear disk stack centrifuges that result in lower operating costs and more robust processes compared to MF. 2,3 Recently, a number of biopharmaceutical manufacturers have demonstrated cell culture processes that produce mAb titers as high as 25 g/L, accomplished by increasing or maintaining the viable cell density (VCD) over a longer duration. 4,5 High VCD generally corresponds to higher packed cell volumes (PCV) or solids level that range from 15 to 40%.…”

“…4 These high solids level easily exceed the capacity of a disk stack centrifuge to adequately clarify the cell broth containing 10-12% solids without a significant loss of product. 2 Along with the high VCD, the level of non-viable cells and sub-micron cellular debris produced in these higher titer cell culture processes is significantly higher than a typical cell culture process. 1 This sub-micron cellular debris is not removed by a disk stack centrifuge, and results in the fouling of the MF or the downstream harvest filtration train.…”

“…1 This sub-micron cellular debris is not removed by a disk stack centrifuge, and results in the fouling of the MF or the downstream harvest filtration train. [1][2][3]6,7 Thus, the limitations of the disk stack centrifuge or MF methods are apparent with high VCD cell culture processes.…”