Other types of fermentations:
The butyric fermentation is the transformation of plant carbohydrates such as starch and cellulose, in butyric acid (CH3-CH2-CH2-COOH) by the action of anaerobic bacteria of the species Clostridium butyricum and Bacillus amilobacter in the absence of oxygen. It is produced from lactose with the formation of butyric acid, H2, and CO2.
Butyric fermentation is very important, since it participates in the decomposition of plant remains that fall to the ground. It is characterized by the appearance of putrid and unpleasant odors.
Enteric bacteria, such as Escherichia, Shigella, Salmonella, and Vibrio, perform mixed acid fermentation. It is a type of anaerobic fermentation, in which pyruvic acid is obtained from glucose, and from this, a complex mixture of acids, mainly lactic acid, acetate, succinate and formate as well as ethanol (from Acetyl CoA) and equal amounts of H 2 and CO 2 (from formate). This causes large amounts of gas to be generated and the medium to acidify.
The putrid fermentation or putrefaction differs from other fermentations because the substrates are degraded protein substances.
Some bacteria such as Bacterium linens or Clostridium sporogenes are those that carry out this fermentation, obtaining as products, organic and malodorous substances such as indole, cadaverine, skatole, which give the smell to the corpses of animals and plant remains.