Polyphasic taxonomy of acetic acid bacteria: an overview of the currently applied methodology.

Acetic acid bacteria are Gram-negative, obligate aerobic bacteria that have the ability to incompletely oxidize alcohols or sugars to organic acids as end products. They are widespread in nature and most of them are capable to oxidize ethanol as substrate to acetic acid. This characteristic makes that acetic acid bacteria are often involved in foods and beverages, either in a beneficial, neutral or detrimental way, and therefore they have been studied extensively. The taxonomy of acetic acid bacteria has undergone many changes in the last 30 years. The early classification systems for these bacteria were based on morphological and biochemical characteristics. Today, the acetic acid bacteria are classified as the consensus result of a polyphasic analysis, combining phenotypic, chemotaxonomic and genotypic data. The present review aims at showing the various methods currently applied as well as their taxonomic resolution.