Propionhappekäärimine

Propionhappekäärimine, also known as propionic acid fermentation, is a metabolic process carried out by certain bacteria, primarily Propionibacterium species. In this process, sugars or other carbohydrates are converted into propionic acid, acetic acid, carbon dioxide, and water. This biochemical pathway is an anaerobic fermentation, meaning it occurs in the absence of oxygen.

The key enzymes involved in propionic acid fermentation break down pyruvate, an intermediate product of glycolysis. Pyruvate is then converted through a series of steps, often involving the vitamin B12 coenzyme, into propionyl-CoA, which is ultimately transformed into propionic acid. Acetic acid is typically produced as a co-product.

Propionhappekäärimine plays a significant role in various industrial applications. It is crucial in the production of Swiss cheese, where the carbon dioxide generated contributes to the characteristic holes, and the propionic acid contributes to the nutty flavor. This fermentation is also utilized in the production of other fermented foods and is explored for the biosynthesis of propionic acid, a chemical used in pharmaceuticals and as a preservative. Some bacteria that perform this fermentation can also degrade amino acids, adding another layer to their metabolic capabilities. Understanding this process is vital for controlling microbial activity in food production and for harnessing its potential in biotechnology.