Propionsyrajäsning

Propionsyrajäsning, also known as propionic acid fermentation, is a metabolic process carried out by certain bacteria, particularly those belonging to the Propionibacterium genus. This type of fermentation is characterized by the production of propionic acid as a major end product, along with other short-chain fatty acids such as acetic acid and succinic acid. The process typically begins with the breakdown of carbohydrates, such as glucose, through glycolysis to produce pyruvate. Pyruvate is then further metabolized via a series of enzymatic reactions to yield propionic acid.

Propionic acid fermentation plays a significant role in several natural and industrial processes. In the dairy industry, it is responsible for the characteristic flavor and eye formation in Swiss cheese. Propionibacteria metabolize lactate, a byproduct of lactic acid fermentation by other bacteria present in the cheese, producing carbon dioxide gas which forms the characteristic holes, and propionic acid which contributes to the nutty flavor.

Beyond dairy products, propionic acid fermentation is also found in the hindgut of ruminant animals, where it contributes to the energy supply of the host. The propionic acid produced is absorbed and can be utilized as a gluconeogenic precursor. In some industrial applications, propionic acid is synthesized through fermentation for use as a food preservative and antifungal agent, often in the form of its salts, calcium propionate and sodium propionate. The ability of propionic acid to inhibit the growth of molds and some bacteria makes it an effective agent in preventing spoilage.