Bioreactors & Fermenters

Bioreactors can be separated into different types based on their material of construction, mechanism of mixing, working volume and overall purpose.

The most prominent disctintion is usually made between single-use and multi-use equipment. While for single-use bioreactors the disposable culture vessel is  made out of a plastic material, multi-use vessels are made from glass or stainless steel and require cleaning and sterilization between process runs.

A very common mechanism of mixing is via a central stirring element in the culture vessel. This stirred-tank design has long been the gold standard for stainless steel bioreactors and is still followed for most single-use bioreactor systems. However, wave-mixing, or rocking motion technology can be a good alternative for shear stress sensitive cell lines. Here, mixing of gasses and nutrients is achieved through a rocking motion of the bioreactor. 

As bioreactors can have working volumes as small as a few milliliter to up to several thousand liter, it is often differentiated between lab-scale, pilot scale and manufacturing scale bioreactor systems. A special subset of lab-scale bioreactors are multiparallel systems that allow multiple culture experiments to be run at the same time.

Finally, a distinction of bioreactor types is often made between mammalian cell culture and microbial culture bioreactors. Both cell types have very different requirements to their culture conditions, which is reflected in the design and configuration of specialized bioreactor systems. 

In Europe “fermentor” and “bioreactor” are synonyms. In the US however, the term “fermentor” is dedicated for microbial systems and “bioreactor” is used for animal cell cultivation systems.