What is the process of separating and purifying expressed proteins/products before marketing called?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Downstream processing.
A recombinant product made in a bioreactor is mixed with cells, culture medium and other substances. Before it can be sold, it must be separated and purified, then made into a formulation with preservatives and tested. These steps after the biosynthetic stage are together called downstream processing.
Option (1) Recombinant protein. — Incorrect. A recombinant protein is the product itself, made from a foreign gene in a host. It is not the name of a process.
Option (2) Transformation. — Incorrect. Transformation is the step in which a host cell takes up recombinant DNA. It comes before the product is made, not after.
Option (3) Downstream processing. — Correct. Downstream processing is the series of steps, mainly separation and purification, that turn the raw product into a finished product ready for marketing.
Option (4) Upstream processing. — Incorrect. ‘Upstream’ would mean the steps before the product is made, such as preparing the culture. Purification comes after the biosynthetic stage.
NCERT Extract:
Downstream Processing – “After completion of the biosynthetic stage, the product has to be subjected through a series of processes before it is ready for marketing as a finished product. The processes include separation and purification, which are collectively referred to as downstream processing. The product has to be formulated with suitable preservatives. Such formulation has to undergo thorough clinical trials as in case of drugs.”