- published: 29 Nov 2013
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Lactobacillus, is a genus of Gram-positive facultative anaerobic or microaerophilic rod-shaped bacteria. They are a major part of the lactic acid bacteria group. In humans they are part of the vaginal microbiota. Many species in this genus have had their genome sequenced.
Lactobacillus is Gram-positive (they retain crystal violet dye), facultative anaerobe (they can produce energy through glycolysis and fermentation when oxygen is not present). Lactobacillus is a member of the lactic acid bacteria group (its members convert lactose and other sugars to lactic acid).
Many lactobacilli operate using homofermentative metabolism (they produce only lactic acid from sugars), and some species of lactobacilli use heterofermentative metabolism (they can produce either alcohol or lactic acid from sugars). They are aerotolerant despite the complete absence of a respiratory chain. This aerotolerance is manganese-dependent and has been explored (and explained) in Lactobacillus plantarum. Many lactobacilli do not require iron for growth and have an extremely high hydrogen peroxide tolerance.