Shake flasks are used for growing and mixing the desired materials on a small scale in the laboratory. A large scale production of desired biotechnological product is done by using 'bioreactors'. Besides better aeration and mixing properties, the bioreactors have following advantages-
(i) Small volumes of cultures are periodically withdrawn from the reactor for sampling.
(ii) It has a foam control system, $\mathrm{pH}$ control system and temperature control system.
(iii) Facilitates even mixing and oxygen availability throughout the bioreactor.