What is the Difference Between Pasteur Effect and Crabtree Effect?

The Pasteur Effect and Crabtree Effect are both related to the fermentation process in yeast, but they are induced by different factors.

The Pasteur Effect is induced by the lack of oxygen, which inhibits the fermentation process. In the absence of oxygen, yeast cells switch to anaerobic glycolysis, a less efficient energy-producing pathway that results in the production of ethanol as a byproduct. This effect was discovered by Louis Pasteur in the 19th century.

On the other hand, the Crabtree Effect is induced by excess glucose. In this case, yeast produces ethanol in aerobic conditions at high glucose concentrations. This phenomenon is also known as "inverted Pasteur effect" and was suggested by Crabtree, who proposed that pathological overgrowths use aerobic glycolysis as a source of energy and glucose. The Crabtree Effect is observed in glucose-limited chemostat cultures run at a series of dilution rates.

In summary, the key difference between the Pasteur Effect and Crabtree Effect is:

• Pasteur Effect is induced by the lack of oxygen, leading to anaerobic glycolysis and ethanol production.
• Crabtree Effect is induced by excess glucose, leading to ethanol production in aerobic conditions.

Comparative Table: Pasteur Effect vs Crabtree Effect

The Pasteur Effect and Crabtree Effect are two closely related phenomena that involve the inhibition of yeast fermentation in response to certain conditions. Here is a table summarizing the differences between the two effects:

Both effects are closely related, but the cause for the effect is different. The Pasteur Effect is induced by the lack of oxygen, while the Crabtree Effect is induced by excess glucose.