DESIGN OF BIOREACTOR

(PICTURE TAKEN FROM WWW>BIOREACTORDESIGN.ORG) AND WWW.CEBTECHSERVICES.COM)


In the first place there is no "hard and fast rule" that fermentation could not be carried out in any vessel or container. You can carry out just about any fermentation process in any vessel from bottles, plastic buoys, tin cans and even test tubes! What fermentation process occurring in the test tube will still occur in the bioreactors!The only problem in using these various types of vessels to carry out the fermentation process, the fermentation process might not be efficiently carried out and might be prone to contaminations and other safety hazards.

In the initial stages of design and construction of a fermentor we have to ask ourselves:
1) How to optimize the conditions that will allow the bioreactor to support high concentration of microorganisms?
2) What sort of fermentation is our fermentor operating for?

A good bioreactor that is designed to support the growth of high concentration of microorganisms must be able to:

1) Provide a good mixing system to ensure that physical, chemical and microbiological conditions are homogenous inside the fermentor. We must ensure that every microorganism in the fermentor will be exposed to a good supply of nutrients and oxygen( for aerobic microorganisms only) and other physical chemical parameters. A good mass transfer is the main requirements in the design of fermentor

2) The geometry design of the fermentor should be a tall cylinder which not only encourages good mixing and transfer of oxygen but good circulation of the fermentation broth. One of the main parameters that influence the efficiency of mass transfer of oxygen is the path of theoxygen and time in contact with the broth.

The type of fermentation to be carried out will significantly affect the type and design of the bioreactor.

Aerobic fermentations differ in their requirements from anaerobic fermentation.
Solid substrate fermentation differs in requirement from liquid substrate fermentation.
Mixed culture fermentations differ from pure cultures fermentation. In pure culture fermentations, there is a stringent demand for aseptic conditions compared to septic fermentations.