(a) How has the development of bioreactor helped in biotechnology?
(b) Name the most commonly used bioreactor and describe its working.

(a) Bioreactors are tanks designed to carry out the biochemical processes where bacteria, fungi, plant cells, or mammalian cells are grown in the optimal conditions temperature, pH, substrate, salts, vitamins, oxygen) for the production of biological products. The usefulness of bioreactor in biotechnology are:

1. Gives control over temperature and pressure.
2. Quick check of the given conditions like pH, temperature, pressure etc.
3. Automatic stirrer stirs the culture.
4. Aerators provide oxygen to the system when needed.
5. Safe and efficient.
6. Biotechnological processes occur without adulteration/leakage of inner material into the surroundings.
7. Automated systems.

(b) Simple stirred tank bioreactor

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system, a temperature control system, pH control system and sampling ports so that small volumes of the culture can be withdrawn periodically.