Acetic acid bacteria

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Acetic acid bacteria
Scientific classification
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Alpha Proteobacteria
Order: Rhodospirillales
Family: Acetobacteraceae
Genera

Acetobacter
Acidicaldus
Acidiphilium
Acidisphaera
Acidocella
Acidomonas
Asaia
Belnapia
Craurococcus
Gluconacetobacter
Gluconobacter
Granulibacter
Kozakia
Leahibacter
Muricoccus
Neoasaia
Oleomonas
Paracraurococcus
Rhodopila
Roseococcus
Rubritepida
Saccharibacter
Stella
Swaminathania
Teichococcus
Zavarzinia

Acetic acid bacteria are bacteria that derive their energy from the oxidation of ethanol to acetic acid during fermentation. They are Gram-negative, aerobic, rod-shaped bacteria.

The acetic acid bacteria are found in nature where ethanol is being formed as a result of yeast fermentation of sugars and plant carbohydrates. They can be isolated from the nectar of flowers and from damaged fruit. Other good sources are fresh apple cider and unpasteurized beer which has not been filter sterilized. In these liquids the acetic acid bacteria grow as a surface film due to their aerobic nature and active motility. Vinegar is produced when acetic acid bacteria act on alcoholic beverages such as wine.

Some genera, such as Acetobacter, can eventually oxidize acetic acid to carbon dioxide and water using Krebs cycle enzymes. Other genera, such as Gluconobacter, don't further oxidize acetic acid, as they do not have a full set of Krebs cycle enzymes.

Some acetic acid bacteria, notably Acetobacter xylinum, are known to synthesize cellulose, something normally only done by plants.

As these bacteria produce acid, they are unusually acid tolerant, growing well below pH 5.0, although the pH optimum for growth is 5.4-6.3.

[edit] References

Saravanan VS, Madhaiyan M, Osborne J, Thangaraju M, Sa TM 2008 Ecological occurrence of Gluconacetobacter diazotrophicus and nitrogen-fixing Acetobacteraceae members: their possible role in plant growth promotion.Microb Ecol. Jan;55(1):130-40. Epub 2007 Jun 17. Review.][1]

Yamada Y and Yukphan P. (2008) Genera and species in acetic acid bacteria Int. J. Food Microbiol. Volume 125, Issue 1, 30 June 2008, Pages 15–24. [2]

Cleenwerck I. and De Vo P. (2008) Polyphasic taxonomy of acetic acid bacteria: An overview of the currently applied methodology Int. J. Food Microbiol. Volume 125, Issue 1, 30 June 2008, Pages 2–14.[3]