<P> Lactic acid is hygroscopic . DL - lactic acid is miscible with water and with ethanol above its melting point which is around 17 or 18 ° C. D - lactic acid and L - lactic acid have a higher melting point . </P> <P> 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 . 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 . The concentration of blood lactate is usually 1--2 mmol / L at rest, but can rise to over 20 mmol / L during intense exertion and as high as 25 mmol / L afterward . </P> <P> In industry, lactic acid fermentation is performed by lactic acid bacteria, which convert simple carbohydrates such as glucose, sucrose, or galactose to lactic acid . These bacteria can also grow in the mouth; the acid they produce is responsible for the tooth decay known as caries . </P> <P> In medicine, lactate is one of the main components of lactated Ringer's solution and Hartmann's solution . 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 . It is most commonly used for fluid resuscitation after blood loss due to trauma, surgery, or burns . </P>

Where is lactic acid found in the body