Question

What is the growth condition for Saccharomyces cerevisiae with glucose as energy source?

(a) Aerobic

(b) Anaerobic

(c) Tryptophan limited

(d) Glucose limited

The question was posed to me in semester exam.

Question is from Kinetics of Cell Substrate Uptake in Cell Culture topic in portion Homogenous Reactions of Bioprocess Engineering

Answer 1

The correct answer is:

(a) Aerobic

Explanation:

Saccharomyces cerevisiae, commonly known as baker's yeast, exhibits different growth behavior depending on the availability of oxygen and the type of energy source.

• When glucose is available as an energy source and oxygen is present, Saccharomyces cerevisiae undergoes aerobic respiration, which is the most efficient way for the yeast to generate energy. In this condition, the yeast will use glucose to produce energy via glycolysis and oxidative phosphorylation, leading to the production of carbon dioxide, water, and ATP.

• In the absence of oxygen (i.e., anaerobic conditions), Saccharomyces cerevisiae will switch to fermentation even when glucose is present, producing ethanol and carbon dioxide instead of water and ATP, although less efficiently.

The options (c) Tryptophan limited and (d) Glucose limited do not specifically apply to the question of growth with glucose as an energy source, as they refer to nutrient limitations rather than oxygen availability.

Therefore, under normal conditions with glucose as the primary energy source, the growth of Saccharomyces cerevisiae is aerobic.