One of the major objective of fermentation in research and industry is to maximise the product titer of the target product in a certain time. This goal can be archieved with high cell density cultivation (HCDC), since high cell densities are a prerequisite for high productivity.
Table 1 gives an rough overview of achievable cell concentration under different cultivation conditions for E. coli.
The most common cultivation system for HCDC is the stirred tank reactor. For a HCDC process strategy the fermentor has to provide besides the standard process measurement and control functions for temperature, pH, DO, agitation and foam the following additional attributes for instance BIOSTAT Bplus, Sartorius BBI Systems GmbH:
* Sophisticated temperature control system for jacketed culture vessels for efficient heat transfer.
* Multi stage DO cascade control for maximum oxygen transfer rates.
* Advanced gassing strategy with oxygen-enrichment capability either via pulsed solenoid valve or mass flow controller.
* Agitation system with high speed and torque.
* Fed- batch operation possibility, feeding with pulsed or variable speed pump controlled via DO controller
* Trend display for graphical on-line process visualisation.
* Connection possibility for a supervisory an control system for advanced control strategies, like control of the specific grow rate.
And easy operation for operators via graphical display with touch screen.
Sartorius BBI Systems GmbH is based in Melsungen, Germany. www.sartorius-bbi-systems.com
