Give information about bioreactors.

(N/A) Small volume cultures cannot yield appreciable quantities of products. To produce in large quantities,the development of bioreactors,where large volumes ($100$-$1000$ litres) of culture can be processed,was required.
Bioreactors can be thought of as vessels in which raw materials are biologically converted into specific products,individual enzymes,etc.,using microbial,plant,animal,or human cells.
$A$ bioreactor provides the optimal conditions for achieving the desired product by providing optimum growth conditions (temperature,$pH$,substrate,salts,vitamins,oxygen).
The most commonly used bioreactors are of the stirring type.
$A$ stirred-tank reactor is usually cylindrical or has 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,a foam control system,a temperature control system,a $pH$ control system,and sampling ports so that small volumes of the culture can be withdrawn periodically.