fermentation

1. A chemical change induced in a complex organic compound by the action of an enzyme, whereby the substance is split into simpler compounds. 2. In bacteriology, the anaerobic dissimilation of substrates with the production of energy and reduced compounds; the mechanism of f. does not involve a respiratory chain or cytochrome, hence oxygen is not the final electron acceptor as it is in oxidation. [L. fermento, pp. -atus, to ferment, from L. fermentum, yeast]

- acetic f., acetous f. f., as of wine or beer, whereby the alcohol is oxidized to acetic acid (vinegar).

- alcoholic f. the anaerobic formation of ethanol and CO₂ from d-glucose. Cf.:Gay-Lussac equation.

- amylic f. f. of potato or corn mash, or other starchy material, by which fusel oil is produced.

- lactic acid f. the production of lactic acid in milk, or other carbohydrate-containing media, caused by the presence of any one of a number of lactic acid bacteria.

* * *

fer·men·ta·tion .fər-mən-'tā-shən, -.men- n

1) a chemical change with effervescence

2) an enzymatically controlled anaerobic breakdown of an energy-rich compound (as a carbohydrate to carbon dioxide and alcohol or to an organic acid) broadly an enzymatically controlled transformation of an organic compound

* * *

n.

the biochemical process by which organic substances, particularly carbohydrate compounds, are decomposed by the action of enzymes to provide chemical energy. An example is alcoholic fermentation, in which enzymes in yeast decompose sugar to form ethyl alcohol and carbon dioxide.

* * *

fer·men·ta·tion (fur″mən-taґshən) the anaerobic enzymatic conversion of organic compounds, especially carbohydrates, to simpler compounds, especially to ethyl alcohol, resulting in energy in the form of adenosine triphosphate (ATP). It differs from respiration in that organic substances rather than molecular oxygen are used as electron acceptors. In the body this takes place in the large intestine, and the process is used commercially in the production of alcohol, bread, vinegar, and other food or industrial products. Fermentation occurs widely in bacteria and yeasts, the process usually being identified by the product formed; e.g., acetic, alcoholic, butyric, and lactic fermentation are those that result in the formation of acetic acid, alcohol, butyric acid, and lactic acid, respectively.