Purple sulfur bacteria Guide, Meaning , Facts, Information and Description
Chromatiaceae
Ectothiorhodospiraceae
Halothiobacillaceae
The purple sulfur bacteria are a group of anaerobic or microaerophilic bacteria. They are capable of photosynthesis, and have a variety of pigments, including yellow and red carotenoids and bacteriochlorophylls a and b, which combine to give them purple, red, brown, or orange colorations. They belong to the proteobacteria, a large group of Gram-negative forms, and make up the order Chromatiales.
The bacteria are often found in sulfur springs and stagnant water.
They are alike in that they use hydrogen sulfide as a primary electron donor, and the process of oxidation of hydrogen sulfide results in the production of intracellular elemental sulfur granules. The oxidation of this elemental sulfur to sulfuric acid is used for energy production.
Example species include Chromatium vinosum, Thispirillum jenense, and Thiopedia rosea. These are grouped into two families, the Chromatiaceae and Ectothiorhodospiraceae. The genus Halothiobacillus may be considered a member of the Chromatiales as well, although it is not photosynthetic.
See also: purple non-sulfur bacteria