The heart of the bioprocess used for the manufacture of a biological product is the bioreactor. It is usually a large vessel with a capacity ranging from 1000 liters to 100,000 liters, made of stainless steel and equipped with an agitation system to keep the contents uniformly mixed and to provide oxygen transfer. The design of the bioreactor should ensure sterlity and provide for containment of the genetically engineered microorganism. The bioreactor includes sensors that permit monitoring of as many critical processes parameters (temperature, pH, dissolved oxygen) as possible so that they can be adjusted to within allowable values.