Question

Which of the following is an upstream process?

(a) Product recovery

(b) Product purification

(c) Media formulation

(d) Cell lysis

I got this question in an internship interview.

My doubt stems from Medium Formulation in section Introduction to Fermentation Processes & Media for Industrial Fermentation of Bioprocess Engineering

Answer 1

The correct answer is:

(c) Media formulation

Explanation:

In bioprocess engineering, the terms upstream and downstream processes refer to different stages of the production cycle:

• Upstream processes involve activities that occur before the production of the desired product, typically focusing on the preparation and cultivation of cells or microorganisms. This includes processes such as:

  • Media formulation (option c) – Preparing the culture medium, which contains all the nutrients necessary for the growth of microorganisms or cells.
  • Inoculation – Introducing the microorganism or cell culture into the bioreactor.
  • Cultivation – Growing the cells or microorganisms in bioreactors under controlled conditions to produce the target product.

• Downstream processes refer to activities that happen after the production of the desired product and involve isolating, purifying, and recovering the product. Examples include:

  • Product recovery (option a) – Extracting the product from the culture medium.
  • Product purification (option b) – Purifying the product to remove contaminants.
  • Cell lysis (option d) – Breaking down cells to release intracellular products, which is often part of the downstream process.

So, media formulation (option c) is an upstream process, as it involves preparing the environment in which the cells or microorganisms will grow.