This pathway was used commercially by the German pharmacy Boehringer Ingelheim in 1895. In 1856, the role of Lactobacillus in the synthesis of lactic acid was discovered by Louis Pasteur. Its structure was established by Johannes Wislicenus in 1873. In 1808, Jöns Jacob Berzelius discovered that lactic acid (actually L-lactate) also is produced in muscles during exertion. The name reflects the lact- combining form derived from the Latin word lac, which means milk. Swedish chemist Carl Wilhelm Scheele was the first person to isolate lactic acid in 1780 from sour milk.
6 Pharmaceutical and cosmetic applications. It is most commonly used for fluid resuscitation after blood loss due to trauma, surgery, or burns. These intravenous fluids consist of sodium and potassium cations along with lactate and chloride anions in solution with distilled water, generally in concentrations isotonic with human blood. In medicine, lactate is one of the main components of lactated Ringer's solution and Hartmann's solution. These bacteria can also grow in the mouth the acid they produce is responsible for the tooth decay known as caries. In industry, lactic acid fermentation is performed by lactic acid bacteria, which convert simple carbohydrates such as glucose, sucrose, or galactose to lactic acid. In addition to other biological roles, L-lactic acid is the primary endogenous agonist of hydroxycarboxylic acid receptor 1 (HCA 1), which is a G i/o-coupled G protein-coupled receptor (GPCR). The concentration of blood lactate is usually 1–2 mM at rest, but can rise to over 20 mM during intense exertion and as high as 25 mM afterward. It does not increase in concentration until the rate of lactate production exceeds the rate of lactate removal, which is governed by a number of factors, including monocarboxylate transporters, concentration and isoform of LDH, and oxidative capacity of tissues. In animals, L-lactate is constantly produced from pyruvate via the enzyme lactate dehydrogenase (LDH) in a process of fermentation during normal metabolism and exercise. On the other hand, lactic acid produced by anaerobic respiration in animal muscles has the ( L) enantiomer and is sometimes called "sarcolactic" acid, from the Greek "sarx" for flesh. Lactic acid produced by fermentation of milk is often racemic, although certain species of bacteria produce solely D-lactic acid. D-Lactic acid and L-lactic acid have a higher melting point. DL-Lactic acid is miscible with water and with ethanol above its melting point, which is about 16 to 18 ☌. A mixture of the two in equal amounts is called DL-lactic acid, or racemic lactic acid. One is known as L-lactic acid, ( S)-lactic acid, or (+)-lactic acid, and the other, its mirror image, is D-lactic acid, ( R)-lactic acid, or (−)-lactic acid. Lactic acid is chiral, consisting of two enantiomers. This higher acidity is the consequence of the intramolecular hydrogen bonding between the α-hydroxyl and the carboxylate group. Compared to acetic acid, its p K a is 1 unit less, meaning lactic acid is ten times more acidic than acetic acid. In solution, it can ionize by loss of a proton to produce the lactate ion CHĢ. The conjugate base of lactic acid is called lactate. It is used as a synthetic intermediate in many organic synthesis industries and in various biochemical industries. Lactic acid is an alpha-hydroxy acid (AHA) due to the presence of a hydroxyl group adjacent to the carboxyl group. Production includes both artificial synthesis as well as natural sources. When in the dissolved state, it forms a colorless solution. It is white in the solid state and it is miscible with water.
It has a molecular formula CH 3CH(OH)COOH.