Observe the figures I and II and answer the following questions.

What is the role of bubbles as shown in figure II?

To increase the oxygen transfer area

The correct answer is Option (1) - To increase the oxygen transfer area

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. 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system, a temperature control system, pH control system and sampling ports so that small volumes of the culture can be withdrawn periodically.