Biotechnology: Principles and Processes — BIOLOGY STD 12 Science — Question

The main objective of almost all recombinant technologies is to produce the desired protein. For this, after cloning the desired gene and optimizing the conditions that induce the expression of the target protein, it is possible to produce them on a large scale. Cells harboring beneficial genes can be cultured in the laboratory on a small scale. The desired protein can be extracted from the culture and purified using various methods of separation. Cells can be multiplied in a continuous culture system, in which used medium is drained from one side and fresh medium is added from the other side so that the cells remain in their most functionally active log (exponential) phase. This culture method is useful for producing more biomass and producing more of the desired protein.
Bioreactors are used to produce these products in large quantities. Bioreactors are like vessels in which raw materials are converted into biologically specific products, individual enzymes etc. using microorganisms, plants, animals and human cells. The bioreactor provides optimum conditions to obtain the desired product. Temperature, pH, substrate, salts, vitamins, oxygen etc. are the optimum conditions for growth. Generally stirring type bioreactor is used the most.
Stirred tank bioreactors are cylindrical. Its curved base helps in mixing of the contents inside the bioreactor. The bioreactor has the availability of oxygen and a stirrer facility for mixing the mixture. Alternatively, air is sent into the bioreactor in the form of bubbles. The bioreactor is equipped with an agitator system, oxygen supply system, froth control system, pH control system, temperature control system and sampling ports from which a small amount of the culture can be taken out from time to time.