An apparatus that maintains optimal conditions for the growth of microorganisms such as bacteria and fungi as well as eukaryotic cells like CHO cells and insect cells, to make products useful to humans. Examples of these products are Biomass or microbial cells, extracellular metabolites (eg. Alcohol, vitamins, antibiotics), intracellular components (eg. Microbial enzymes, recombinant proteins), and transformation substrates (eg. Phenylacetylcarbinol, methane). Fermenters are suitable for pilot and production scale of biopharmaceuticals such as vaccines, recombinant proteins, and monoclonal antibodies in a GMP regulated environment.