ABSTRACT
Bioreactors can be defined as ‘chemical reactors’ where a series of reactions, catalysed by biological agents, are processed. Biological agents, also known as biocatalysts, can be basically of two types: enzymes and/or cell organelles; and living cells, which can be of vegetable, animal or microbial origin. However, in the present text, only those used with living organisms will be considered as bioreactors. In such bioreactors, in addition to the gas disperser, which is used to distribute the air in the system, circulation of the fluid is provided by rotating devices located along the height of the central axis of the motor. Mass balance equations for cells, limiting substrate and metabolic product in the three modes of operation are outlined in the following topics. In order to simplify this description, the same hypothesis used in the mass balance for cells is considered, i.e., an equilibrium situation. The mass balances presented below are described for the continuous process in a single stage.
