Crossflow filtration for CHO cell separation by microfiltration using crossflow systems

Chinese Hamster Ovary (CHO) cells are used for fermentation of high value proteins in the pharmaceutical- and biotechnology industry. During the fermentation process the cells are grown under specific conditions in a defined media. The CHO cells produce extra cellular proteins. Separation and purification of these proteins result in the final product of high value. The production steps utilized in any bio-pharmaceutical process must deliver the target protein with high purity and yield. The first step in the production process is the separation of cells from the rest of the fermentation broth. Currently, stacked depth filters are used in this separation. The disadvantages with this method are:- 1) low product yield (high hold-up/wetting volume) and 2) the messy "clean-up" that is inherent with stacked filters. One of the main process requirements is that the CHO cell removal be accomplished with low cell mortality. This eases the subsequent process steps to purify the target protein with high yields free of DNA and other intracellular proteins. Additionally, the CHO cells can be reused.