Assume you are working for a chemical company and are responsible for growing a yeast culture that produces ethanol. The yeasts are growing well on the glucose medium and there is plenty of oxygen but they are not producing alcohol. What is true about this situation?

Question:

Assume you are working for a chemical company and are responsible for growing a yeast culture that produces ethanol. The yeasts are growing well on the maltose medium but are not producing alcohol. What is the most likely explanation?

a - the maltose is toxic

b - O₂ is in the medium

c - not enough protein is provided

d - the temperature is too low

e - the temperature is too high

Answer:

The correct option is;

b - O₂ is in the medium

Explanation:

The production of ethanol from glucose by the introduction of yeasts is known as fermentation process.

Yeast + Glucose → Ethanol + CO₂

The yeast ferments the glucose anaerobically to produce energy, CO₂ and ethanol

Therefore, ethanol production takes place in the absence of oxygen.

When oxygen is present, the yeast undergoes aerobic respiration, it breathes to produce energy by consuming the glucose and the oxygen. In the process, water and carbon dioxide are also produced.

Yeast + Glucose + Oxygen → H₂O + CO₂.