Constructive improvement of the ultrasonic separation device ADI 1015

The use of the ultrasonic separation device is a very important step in the direction for improving animal cell bioreactor cultures. However, the norm al construction of the ultrasonic separation device ADI 1015 has an inheren t disadvantage in pumping the cell suspension continuously through the devi ce by using a peristaltic pump. The cells are taken out of the reactor and are transported to the side inlet located below the separation chamber of t he device. This cycling leads to cell death and a considerable reduction of the viable cell density. The modification of the configuration of the devi ce (no circulation of the cell suspension through the retention device; dur ing approximately 9 minutes cell-free supernatant is extracted; every 9 min ute for about one minute, the volume which is equivalent to the interior vo lume of the chamber and the tubing connecting the device to the reactor, is flushed back in order to return the retained cells back to the reactor) al lows cell densities from 10(6) to 2.7 x 10(6) c/ml with a viability of at l east 90% (tested for the shear sensitive insect cell line High Five), where as the maximal cell densities obtained were 0.76 x 10(6) c/ml for the perio d of continuous culture and 10(5) c/ml at the end of the use of the device in the classical mode.