5. Bioprocessing & Industrial Biotechnology

Downstream Processing — Quiz

Test your understanding of downstream processing with 5 practice questions.

Practice Questions

Question 1

A biotechnology company is developing a novel therapeutic protein. After fermentation, the broth contains cells, cell debris, and the target protein. Which of the following sequences of downstream processing steps is most appropriate to obtain a highly purified and stable protein product?

Question 2

In the context of protein purification, a researcher observes that a target protein aggregates significantly during a low-salt wash step in ion-exchange chromatography. Which of the following modifications would be most effective in mitigating this aggregation while maintaining separation efficiency?

Question 3

A recombinant enzyme is being purified from a bacterial lysate. After initial clarification, the enzyme is passed through an anion-exchange column at $\text{pH 8.0}$. The enzyme binds to the column, while many contaminants pass through. To elute the enzyme, the buffer's ionic strength is gradually increased. If the enzyme has an isoelectric point (pI) of $\text{6.5}$, which of the following statements best explains its behavior on the column?

Question 4

During the formulation of a monoclonal antibody (mAb) therapeutic, a critical challenge is preventing aggregation and maintaining long-term stability. Which of the following excipients is primarily added to mitigate aggregation by preferentially interacting with the protein surface, thereby reducing protein-protein interactions?

Question 5

A biopharmaceutical company is scaling up the purification of a viral vaccine. After cell lysis and clarification, the viral particles need to be concentrated and exchanged into a new buffer for the next purification step. Which of the following membrane separation techniques is most suitable for this purpose, considering the size and fragility of viral particles?