Ultrasonic Cell Separation — Production of Monoclonal Antibodies in Continuous Perfusion Cultures

The production of monoclonal andbodies (mABs) in small gram quanddes is mosdy done in batch or fed batch fermentations in stirred tank reactors. The use of perfusion systems tike hollow fibre or fluidized bed fermenters is considered as too laborious or not suitable in this scale. An alternative way is the use of a small continuously perfused stirred tank bioreactor with an ultrasonic cell setder (UCS) mounted on top of it as cell retention device. The cells are trapped in a standing wave ultrasonic field, which is switched on and off periodically to allow the cells to settle back into the fermenter. In contrast to other filtration devices like crossflow or microfilters the ultrasonic cell setder works without direct mechanical impact on the cells. This means that clogging of the device is avoided, which results in an excellent long-term stability.