Concentrated fed-batch processes
are biotechnological procedures in which not only the cells but also the target product are retained in the bioreactor (via micro- and ultrafiltration membranes) 44. The pore size or the MWCO is 2 to 3 times smaller than the product. With this cultivation mode, antibody productions with mammalian cells reached cell densities of more than 108 cells mL-1 and product titers larger than 10 g L-1. See ATF-modules, crossflow filtration, TFF and XD-technology.