Question

Which of the following is not a component of downstream processing?
A. Preservation
B. Expression
C. Separation
D. Purification

Answer 1

Hint: The downstream processing is the last step of Recombinant DNA Technology (RDT). In addition, it is the stage when the final product is recovered by removing the waste matter from it and then it is cleaned, decontaminated, and stored.

Complete answer: Downstream processing is the final stage of the process of Recombinant DNA Technology. After the fermentation has occurred the desired product needs to be recovered and purified. Hence, the downstream process involves the separation, purification, and preservation of the desired products. The contents of the fermenter are separated into a solid and a liquid part. This is done by the centrifugation process or filtration process. The solid part consists of the cells. The liquid also contains some part of the desired product. Using biochemical separation and purification techniques like drying, solvent extraction, chromatography, and distillation. Lastly, the product is preserved with the help of preservatives. Vigilant quality-control testing is done before the product is released into the market. If the developed product is a drug then clinical trials are held. Thus, based on the above information we can conclude that expression is not a component of the downstream processing.
Hence, the correct answer is option (B).

Note: Downstream processing is a very important step in Recombinant DNA Technology. Its importance can be realized from the fact that the Eli Lilly Company, which is an American company, has employed more than ninety percent of its 200-strength staff of the human insulin plant to this single process.