strictly aerobic, nonsporiferous, gram-negative, usually motile, flagellate, rodlike bacteria measuring 0.6 × 3 micrometers. Acetic-acid bacteria, which belong to the genus Acetobacter, oxidize monohydric and polyhydric alcohols. Ethyl alcohol is oxidized to acetic acid:
The acetic acid thus formed can be further oxidized to CO2 and H2O
Acetic-acid bacteria form a film on the surface of liquid nutrient media; on solid media they form large, smooth, slimy, colorless colonies that glisten. The bacteria are found in nature on fruits and vegetables. Commercially, they are used to produce vinegar from wine or dilute alcohol; they are also used in the synthesis of vitamin C (ascorbic acid) for oxidizing sorbitol to sorbose. Acetic-acid bacteria cause the souring of wine, beer, and certain food products.