The BDC has two fermention systems (bioreactors) that allow scale up and enhanced control of microbial liquid phase culture for comparison with preliminary small-scale shake flask experiments. Both bioreactors have controls for regulation of pH, temperature, dissolved oxygen (DO) and foaming throughout the microbial growth period of specific experiments. In addition, both vessels have systems in place for sterile sampling so that other analysis can be conducted mid-fermentation without damaging the integrity of the system. Data from the fermentation runs is collected by directly linking a computer to the bioreactor control panels for both vessels and can, subsequently, be analysed offline.
5 litre bioreactor
The smaller unit is a glass jacket 6.2 litre vessel with a working volume of 5 litres that is controlled by a Sartorius Biostat Bplus unit.
- Temperature is controlled by a water jacket that is fed through a heater unit within the control unit.
- Additions to regulate the pH and apply antifoam oil are supplied through three peristaltic pumps attached to the control unit. The pH is monitored by a Hamilton Easyferm pH probe and the DO by the Hamilton Visiferm DO probe
- Air is supplied via a ring sparger and DO is regulated using Rushton and/or marine impellers.
- Sterility of the vessel is accomplished using a Priorclave autoclave located within the fermenter unit.
30 litre bioreactor
The larger of the two units is a 42 litre vessel, with a 30 litre working volume, steam in place fermenter. This is a stainless steel jacketed vessel connected to a Camptel steam boiler and a Frigomix cooling unit. The bioreactor is controlled using the Sartorius Biostat Cplus unit
This unit can be sterilised at 121oC using the steam generator; this also allows for in situ sterilisation of media thus reducing potential for contamination. Subsequent temperature regulation is accomplished using the boiler and cooling unit in tandem.
Similar to the 5 litre vessel, the pH and DO are monitored using the Hamilton Easyferm and Visiferm probes respectively. Also, the additions are made with a similar peristaltic pump arrangement and air is supplied also via a ring sparger.
For more information about the bioreactors, please speak to David.