Question

Low dissolved oxygen concentrations leads to

(a) Low biomass yields

(b) High biomass yields

(c) Equal biomass compositions

(d) No effect on biomass yields

This question was addressed to me in an interview.

Question is from Oxygen Transfer in Fermenters topic in chapter Mass Transfer of Bioprocess Engineering

Answer 1

The correct answer is (a) Low biomass yields

The explanation: Water with high concentrations of dissolved minerals such as salt will have a lower DO concentration than fresh water at the same temperature. Low dissolved oxygen (DO) primarily results from excessive algae growth caused by phosphorus. As the algae die and decompose, the process consumes dissolved oxygen.