Question

Downstream processing does not include which of the given processes?
I. Transformation of host cell
II. Separation of product from culture medium
III. Product purification
IV. Sampling from bioreactors

• A. I and II
• B. II and III
• C. I and IV
• D. I, III and IV

Answer 1

The correct option is C I and IV

The process of obtaining the foreign gene product from a living source, like a genetically engineered organism (microbial, plant or human cells), is known as bioprocessing. It consists of two components - upstream processing and downstream processing.

The biosynthetic phase consisting of growing the desired cells, from which the product is likely to be derived in bioreactors, at a large scale is known as upstream processing.

Bioreactors are provided with sampling ports for withdrawing or sampling small volumes of cultures at regular intervals. This is done in order to optimize the bioreactor functions, check growth rates, etc.

Once the concentration of the product expressed by the growing host cells in the bioreactor reaches the optimal quantity, it needs to be extracted out for use.

Separation of the expressed gene product from the culture media and its purification are done. These are the components of downstream processing.

This is followed by formulation of the desired product with preservatives to increase its shelf life. Further, strict clinical trials and quality control measures are taken to ensure that the product is ready to be marketed for human use.

Thus, sampling of cultures from the bioreactors and transformation of host cells are not components of downstream processing.