Pasteur effect - cessation of fermentation in the presence of oxygen . Discovered by Louis Pasteur in 1857. Pasteur showed that aeration of the yeast broth accelerates the growth of yeast, while under anaerobic conditions the growth rate decreases [1] .
From the point of view of physiology, the essence of the effect is the switching of microorganisms from anaerobic energy metabolism ( fermentation ) to aerobic ( respiration ), which is much more energetically beneficial.
Explanation of the effect
The effect is explained by the fact that, since yeast are facultative anaerobes , they can receive energy using two different metabolic pathways. At a low oxygen concentration, the product of glycolysis , pyruvate , is converted to ethanol and carbon dioxide with a low energy output (2 moles of ATP per mole of glucose ). If the oxygen concentration is high, pyruvate is converted to acetyl-CoA , which can then be used in the Krebs cycle , which increases the efficiency to 38 mol of ATP per 1 mol of glucose [2] .
Under anaerobic conditions, the rate of glucose metabolism is faster, but the amount of ATP formed (as already mentioned) is less. Under aerobic conditions, the rate of glycolysis decreases, since increasing the concentration of ATP allosterically inhibits the enzyme phosphofructokinase 1 , the third enzyme of the glycolysis pathway. Thus, it is more beneficial for yeast to use the Krebs cycle under aerobic conditions, since less glucose is required to synthesize more ATP.
Notes
- ↑ Pasteur Effect .
- ↑ Lehninger, Albert. Principles of Biochemistry. - New York, NY: WH Freeman and Company, 2008 .-- P. 539. - ISBN 0-7167-7108-X .
Links
- The Pasteur Effect - an article from the Great Soviet Encyclopedia .
- Studio article
- Article on medbiol.ru