Heterolactic fermentation

Definition

Heterolactic fermentation is a metabolic process in which glucose is converted into lactate, ethanol, and carbon dioxide. It involves multiple pathways including the pentose phosphate pathway.

5 Must Know Facts For Your Next Test

1. Heterolactic fermentation produces both lactic acid and ethanol as major end products.
2. This type of fermentation occurs in certain bacteria such as Leuconostoc and some species of Lactobacillus.
3. The process involves the enzyme phosphoketolase, which splits xylulose-5-phosphate into glyceraldehyde-3-phosphate and acetyl phosphate.
4. In heterolactic fermentation, about half of the glucose molecule's carbon ends up as lactate while the other half is split between ethanol and carbon dioxide.
5. This fermentation pathway is less energetically efficient than homolactic fermentation because it results in fewer ATP molecules per glucose molecule.

Review Questions

• What are the main end products of heterolactic fermentation?
• Which enzyme plays a crucial role in the heterolactic fermentation pathway?
• Name one bacterial genus that utilizes heterolactic fermentation.

Related terms

Homolactic Fermentation: A type of fermentation where glucose is converted solely into lactic acid.

Pentose Phosphate Pathway: A metabolic pathway parallel to glycolysis that generates NADPH and pentoses.

Phosphoketolase: An enzyme involved in breaking down sugars during heterolactic fermentation.