A bioreactor may refer to any manufactured or engineered device or system that supports a biologically active environment. A bioreactor/fermenter is equipment in which a controlled environment is provided for the fermentation processes. It is the system which helps to grow, maintain the micro organisms/ cells in controlled environment.

Generally the system used for Microbial fermentation process is called a Fermenter. AND the one which is used for cell culture (mammalian/insect cell) fermentation process is called Bioreactor.