Propionibacteria. The most notable one is the Cutibacterium acnes (formerly known as Propionibacterium acnes), which lives mainly in the sebaceous glands of the skin and is one of the principal causes of acne. Propionate is observed to be among the most common short-chain fatty acids produced in the large intestine of humans by gut microbiota in response to indigestible carbohydrates (dietary fiber) in the diet. The role of the gut microbiota and their metabolites, including propionate, in mediating brain function has been reviewed. A study in mice suggests that propionate is produced by the bacteria of the genus Bacteroides in the gut, and that it offers some protection against Salmonella there. Another study finds that fatty acid propionate can calm the immune cells that drive up blood pressure, thereby protecting the body from damaging effects of high blood pressure. Bacteriology The Bacteria species Coprothermobacter platensis produces propionate when fermenting gelatin. Propionate salts and esters The propionate , or propanoate''', ion is , the conjugate base of propionic acid. It is the form found in biological systems at physiological pH. A propionic, or propanoic, compound is a carboxylate salt or ester of propionic acid. In these compounds, propionate is often written in shorthand, as or simply . Propionates should not be confused with propenoates (commonly known as acrylates), the ions/salts/esters of propenoic acid (also known as 2-propenoic acid or acrylic acid). Examples Salts Sodium propionate Potassium propionate Calcium propionate Zirconium propionate Esters Methyl propionate Ethyl propionate Propyl propionate Pentyl propionate Fluticasone propionate See also List of saturated fatty acids List of carboxylic acids References External links NIST Standard Reference Data for propanic acid International Chemical Safety Card 0806 NIOSH Pocket Guide to Chemical Hazards The Propionic Acids. Gastrointestinal Toxicity in Various Species Propionic Acid Technical Data Sheet E-number additives Fatty acids Foul-smelling chemicals