Acetic Acid Bacteria

Acetic acid bacteria are very prevalent in nature and are well adapted to growth in sugar-rich and alcohol-rich environments. Acetic acid bacteria cells generally have an ellipsoidal or rodlike form, with dimensions of 0.6-0.8 μm by 1-4 μm. Acetic acid bacteria belong to the Acetobacteraceae family. The classification of acetic acid bacteria in grapes and wine has been updated over time in view of new taxonomy data. The isolation of acetic acid bacteria from grape must or wine is carried out by culture on a solid nutrient medium. The bacteria of the Acetobacter , Gluconacetobacter , and Gluconobacter genera are obligate aerobes with an exclusively respiratory metabolism. The oxidative fermentation pathway is the main originality of the acetic acid bacteria metabolism. Barrel or tank aging also entails racking for clarifying and aerating the wine–causing limited oxidations that are indispensable to wine evolution.