Propionsäuregärung

Propionsäuregärung, also known as propionic acid fermentation, is a metabolic process carried out by certain microorganisms, primarily bacteria, to convert sugars into propionic acid. This anaerobic fermentation pathway is distinct from lactic acid fermentation, which produces lactic acid as the primary end product. Propionic acid fermentation typically starts with the breakdown of glucose into pyruvate, similar to other fermentation pathways. Pyruvate is then further metabolized through a series of enzymatic reactions.

The specific end products of propionic acid fermentation can vary depending on the microorganisms involved and the environmental conditions. However, common products include propionic acid, acetic acid, succinic acid, carbon dioxide, and sometimes ethanol. The production of propionic acid is a key characteristic, and it's often accompanied by the generation of other volatile fatty acids.

This fermentation process plays a significant role in several natural environments and industrial applications. In the rumen of ruminant animals, propionic acid fermentation is a major source of energy for the animal, as propionic acid can be converted to glucose in the liver. In food production, it is utilized in the ripening of certain cheeses, contributing to their characteristic flavor and aroma. For example, the formation of the "eyes" in Swiss cheese is due to the carbon dioxide produced during propionic acid fermentation by Propionibacterium species. Industrially, propionic acid itself is used as a preservative in animal feed and as a precursor in the synthesis of various chemicals.