noun, plural: propionic acids
A naturally occurring carboxylic acid with the formula: C3H6O2
Propionic acid is a carboxylic acid although it may also be considered as a saturated fat. However, it only has three carbon atoms in a chain. It occurs as a soluble liquid. Propionic acid is found in milk products and in sweat. It has an unpleasant smell similar to a body odour. It is naturally produced through bacterial fermentation. Several species of the genus Propionibacterium live as commensals or parasites on the human skin (such as on sweat glands and sebaceous glands) where they are capable of producing propionic acid using transcarboxylase enzymes. P. acnes is one of the most notable species. It lives chiefly in the sebaceous gland, and is associated with acne. Propionibacterium species also live in the large intestines of humans where they produce propionic acid through fermentation of dietary fiber. This group of bacteria is also found in the intestine of the ruminants.
Propionic acid may also be produced synthetically as it is used in making perfumes and for inhibiting molds in bread.
Word origin: Greek prōtos (“first”) + piōn (“fat”)
- Propanoic acid
- ethanecarboxylic acid
- methylacetic acid