By definition, a bioreactor is a system in which a biological conversion is affected. Although this definition can apply to any conversion involving enzymes, microorganisms, and animal or plant cells, for the purposes of this article, we will limit the definition. The bioreactors referred to here include only mechanical vessels in which (a) organisms are cultivated in a controlled manner and/or (b) materials are converted or transformed via specific reactions.
In other words, bioreactor made to make our own conditions that required for optimum result of fermentation.