Q.

Stirred-tank bioreactors have been designed for:                  [2016]

1 purification of product  
2 addition of preservatives to the product  
3 availability of oxygen throughout the process  
4 ensuring anaerobic conditions in the culture vessel  

Ans.

(3)

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.