Question

Which of the following would be chosen for best yield if we want to produce a recombinant protein in large amounts?

• A. Any of the above
• B. A laboratory flask of large capacity
• C. A continuous culture system
• D. A bioreactor without ports

Answer 1

The correct option is C A continuous culture system

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.

Recombinant proteins are proteins encoded by recombinant DNA. Genes for recombinant proteins are cloned in a vector which supports the expression of the gene and production of the proteins in a competent host cell.

For large scale production of recombinant proteins, a continuous culture system is preferred.

In this method, the used medium is removed from one side of the bioreactor and fresh medium is added from the other side. This maintains the cells in their physiologically most active log or exponential phase. It ensures rapid multiplication of the cells. Hence, a larger biomass is obtained leading to higher yields of desired protein.

Laboratory flasks are glass vessels commonly used in the labs for the preparation of culture media and solutions. It will not be enough to generate large scale production of proteins from the recombinant DNA.

A bioreactors possess the following common ports:

• Mixing port - The agitator extends through this into the bioreactor for mixing the contents.
• Reaction port - All the components helping in the proper growth of the cells like pH and temperature control, vessel etc.
• Harvesting port - It permits the withdrawal of the reaction medium. Without ports a bioreactors will not work.

Hence the correct option is
a. A continuous culture system