Bioreactor

==Design==

==Design==

[[File:STR Laboratory Bioreactor.jpg|thumb|Bench-top laboratory bioreactor with vessel for [[Fermentation|fermentation processes]]]]

[[File:USP DSP Plant.jpg|thumb|144x144px|A stainless-steel industrial bioreactor together with a tangential flow filtration system installed in a [[Veterinary medicine|veterinary]] [[vaccine]] production facility.]]

Bioreactor design is a relatively complex engineering task, which is studied in the discipline of [[biochemical engineering|biochemical]]/[[bioprocess engineering|bioprocess]] engineering. Under optimum conditions, the microorganisms or cells are able to perform their desired function with limited production of impurities. The environmental conditions inside the bioreactor, such as temperature, nutrient concentrations, pH, and dissolved gases (especially oxygen for aerobic fermentations) affect the growth and productivity of the organisms. The temperature of the fermentation medium is maintained by a cooling jacket, coils, or both. Particularly exothermic fermentations may require the use of external heat exchangers. Nutrients may be continuously added to the fermenter, as in a fed-batch system, or may be charged into the reactor at the beginning of fermentation. The pH of the medium is measured and adjusted with small amounts of acid or base, depending upon the fermentation. For aerobic (and some anaerobic) fermentations, reactant gases (especially oxygen) must be added to the fermentation. Since oxygen is relatively insoluble in water (the basis of nearly all fermentation media), air (or purified oxygen) must be added continuously. The action of the rising bubbles helps mix the fermentation medium and also "[[air stripping|strips]]" out waste gases, such as carbon dioxide. In practice, bioreactors are often pressurized; this increases the [[Henry's law|solubility of oxygen]] in water. In an aerobic process, optimal oxygen transfer is sometimes the rate limiting step. [[Oxygen]] is poorly soluble in water—even less in warm fermentation broths—and is relatively scarce in [[air]] (20.95%). Oxygen transfer is usually helped by agitation, which is also needed to mix nutrients and to keep the fermentation homogeneous. [[Mixing (process engineering)#Liquid–gas mixing|Gas dispersing agitators]] are used to break up air bubbles and circulate them throughout the vessel.{{citation needed|date=October 2019}}

Bioreactor design is a relatively complex engineering task, which is studied in the discipline of [[biochemical engineering|biochemical]]/[[bioprocess engineering|bioprocess]] engineering. Under optimum conditions, the microorganisms or cells are able to perform their desired function with limited production of impurities. The environmental conditions inside the bioreactor, such as temperature, nutrient concentrations, pH, and dissolved gases (especially oxygen for aerobic fermentations) affect the growth and productivity of the organisms. The temperature of the fermentation medium is maintained by a cooling jacket, coils, or both. Particularly exothermic fermentations may require the use of external heat exchangers. Nutrients may be continuously added to the fermenter, as in a fed-batch system, or may be charged into the reactor at the beginning of fermentation. The pH of the medium is measured and adjusted with small amounts of acid or base, depending upon the fermentation. For aerobic (and some anaerobic) fermentations, reactant gases (especially oxygen) must be added to the fermentation. Since oxygen is relatively insoluble in water (the basis of nearly all fermentation media), air (or purified oxygen) must be added continuously. The action of the rising bubbles helps mix the fermentation medium and also "[[air stripping|strips]]" out waste gases, such as carbon dioxide. In practice, bioreactors are often pressurized; this increases the [[Henry's law|solubility of oxygen]] in water. In an aerobic process, optimal oxygen transfer is sometimes the rate limiting step. [[Oxygen]] is poorly soluble in water—even less in warm fermentation broths—and is relatively scarce in [[air]] (20.95%). Oxygen transfer is usually helped by agitation, which is also needed to mix nutrients and to keep the fermentation homogeneous. [[Mixing (process engineering)#Liquid–gas mixing|Gas dispersing agitators]] are used to break up air bubbles and circulate them throughout the vessel.{{citation needed|date=October 2019}}