Draw the illustration of main bioreactor types and explain the usage of these reactors in bioprocess engineering applications?(Compare the bioreactor types)
(a)Continuous stirred tank bioreactor
A cylindrical vessel with a drive-in central shoe supporting one or more agitators is a continuous stirred tank bioreactor (impellers). At the bottom of the bioreactor, the shaft is fitted. There are varying numbers of impellers depending on the bioreactor's size. The aspect ratio of a bioreactor stirred tank normally varies between 3-5. The aspect ratio is, however, lower than 2 for uses in animal cell culture. Usually 1/3 rd diameter of the rotor is of the diameter of the vessel. The distance between the two sprockets is around 1,2 sprockets. Various types of rotators are used.
(b)Bubble column bioreactor
The air or gas on the base of a column is introduced via drilled pipes or plates or metal micro porous sprayers in the bubble column bioreactor. The air/gas flow rate affects the performance aspects — transmission of O2 and mixing. In order to boost performance, perforated plates can be used in the bubble column bioreactors. The vessel used for bioreactors in bubble columns is generally cylinder with a 4-6 aspect ratio (i.e., height to diameter ratio).
(c) Internal loop airlift
The Internal Loop Airlift Bioreactor features a single tube container that provides indoor liquid flow canals. These bioreactors are basic in design with a preset fermentation rate of volume and circulation.
(d)External loop airlift
The external loop airlift bioreactor has an external loop to circulate the fluid via separate channels. These reactors may be adapted according to varied fermentation requirements. Overall, bioreactors of the airlift are more efficient than bubble columns, especially for denser microorganism suspensions. This is largely because the content mix is better than bubble columns with these bioreactors.
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