The Electron Transport Chain in Metabolism: Fermentation
Glucose
2 Pyruvate
Reduced form of pyruvate
- Fermentation does not use the ETC
- The final electron acceptor is internal: usually it is pyruvate
- Fermentation waste products are released into the medium
- Lactic acid (Streptococcus)
- Mixed acids (formic, acetic, lactic) + CO2 + H2
(E. coli) [Methy Red test]
- Butanediol + CO2 (Enterobacter) [Voges Proskauer test]
- Ethanol + CO2 (Saccharomyces)
- Propionic acid + CO2 (Propionibacterium)
- 2 ATP are made per glucose during glycolysis by substrate
level phosphorylation
- NADH made during glycolysis is re-oxidized in fermentation. The cell does
not convert this reducing power to ATP