Question

Illustrate the design of a bioreactor.
Highlight the difference between a flask in your laboratory and a bioreactor which allows cells to grow in a continuous culture system.

Answer 1

Design of a bioreactor:


Parts of a bioreactor:

Bioreactors are large cylindrical vessels that are used for large scale culturing of cells (plant, animal or microbial cells) to obtain specific gene products for commercial use. A bioreactor provides optimum conditions, such as temperature, pH, nutrients, oxygen (aerobic bioreactors) etc., for the optimum growth of cells under culture.

The given diagram shows a simple stirred tank bioreactor which consists of the following components:

i) A central shaft
ii) Stirrer blades, magnetically coupled to the shaft, for the purpose of stirring
iii) An oxygen delivery system
iv) A foam control machine
v) Temperature and pH control systems
vi) A cooling jacket
vii) Sampling ports for removal of small samples of culture, periodically.

Culture size:

Laboratory flask allows small scale culture. Bioreactors allow large scale culturing upto many litres of volume.

Application:

The culture and desired protein product obtained from the laboratory flask is sufficient enough for testing and preliminary studies. Bioreactors are used for commercial production of recombinant products.

Extraction of product:

In laboratory flasks, the desired product can be extracted only after a certain period of time. Bioreactors allow the flexibility to add fresh medium and extract desired product at any point of time of the culture.

Summary

Criteria	Laboratory flask	Bioreactor
Culture size	Laboratory flask allows small scale culture	Bioreactors allow large scale
Application	The culture and desired protein product obtained from the laboratory flask is sufficient enough for testing and preliminary studies.	Bioreactors are used for commercial production of recombinant products.
Extraction of product	Can be done only after a certain period of time	Addition of fresh medium and extraction of desired product at any point of time of the culture is flexible