Buttersäuregärung

Buttersäuregärung, also known as butyric acid fermentation, is a biological process where carbohydrates are broken down into butyric acid by anaerobic bacteria. This metabolic pathway is predominantly carried out by bacteria belonging to the genus Clostridium, such as Clostridium butyricum and Clostridium kluyveri.

The process typically begins with the breakdown of sugars like glucose or starch into pyruvate through glycolysis. Pyruvate is then further metabolized. In butyric acid fermentation, a key intermediate is acetyl-CoA. Two molecules of acetyl-CoA are converted into acetoacetyl-CoA. Subsequently, acetoacetyl-CoA is reduced to beta-hydroxybutyryl-CoA and then to butyryl-CoA. Finally, butyryl-CoA is dephosphorylated to yield butyric acid, releasing adenosine triphosphate (ATP) as energy. Other end products often include acetic acid, carbon dioxide, and hydrogen gas, depending on the specific bacterial species and environmental conditions.

This fermentation plays a significant role in various ecological niches, including the digestive tracts of animals, particularly ruminants, and in anaerobic environments like soil and sediment. In the gut, it contributes to nutrient cycling and can influence the host's health. Industrially, butyric acid produced through fermentation has applications in the food industry as a flavoring agent and in the production of esters used in perfumes and solvents. However, it is also associated with spoilage in some food products due to its characteristic unpleasant odor. The efficient and controlled production of butyric acid through fermentation remains an area of research.