Observe the figures I and II and answer the following questions.
Identify the statements which are correct with respect to the above figures I and II
A. I represent increased surface area for oxygen transfer
B. Fig II is of simple stirred-tank bioreactor
C. A stirred-tank reactor is usually cylindrical with a curved base
D. The base of the tank is curved to facilitate mixing of the reactor contents
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → C and D only
A. I represent increased surface area for oxygen transfer — Incorrect. The larger area for oxygen transfer comes from the sparged air bubbles, shown on the side of Figure II and labelled “Bubbles”; I is a separate part of the tank.
B. Fig II is of simple stirred-tank bioreactor — Incorrect. Figure I is the simple stirred-tank bioreactor. Figure II, with air bubbled through the culture, is the sparged stirred-tank bioreactor.
C. A stirred-tank reactor is usually cylindrical with a curved base — Correct. This is the usual shape.
D. The base of the tank is curved to facilitate mixing of the reactor contents — Correct. The curved base leaves no corners where the culture could stay unmixed.
NCERT Extract:
Obtaining the Foreign Gene Product – “… A stirred-tank reactor is usually cylindrical or with a curved base to facilitate the mixing of the reactor contents. The stirrer facilitates even mixing and oxygen availability throughout the bioreactor. Alternatively air can be bubbled through the reactor. If you look at the figure closely you will see that the bioreactor has an agitator system, an oxygen delivery system and a foam control system, a temperature control system, pH control system and sampling ports so that small volumes of the culture can be withdrawn periodically.”