Purple sulfur bacteria
Chromatiaceae
Ectothiorhodospiraceae
Halothiobacillaceae
</table>
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
purple non-sulfur bacteria
