Propagation of stable cell lines is verified
by cultivation in bioreactors which are controlled for temperature, ph, oxygen and stirring.
These conditions maintain optimal growth
and production of the cells.
The bioreactors are preferably run on a
continuous mode, enabling constant medium exchange and harvest of the
product. This method of operation protects
unstable proteins from strong degradation
and thus inactivation.

The cells can be cultivated to densities of
2 x 107/ml resulting in production rates of
up to 50 -100 pg/cell/day.
The utilization of 10L bioreactors enables
gram quantities of recombinants to be
produced within a moderate time frame.
Production trials can run for 2-3 months
without loss of productivity and protein quality.