Heliobacteria

 ( Eubacteriales ) 

Heliobacteria are a unique subset of bacteria that process light for energy. Distinguishable from other Phototroph bacteria, they utilize a unique photosynthetic pigment, bacteriochlorophyll g and are the only known Gram-positive phototroph.

They are a key player in Symbiosis nitrogen fixation alongside plants, and use a type I reaction center like green-sulfur bacteria.

(2013). 9780123786319 ISBN 9780123786319

(2009). 9780123739445 ISBN 9780123739445

RNA trees place the heliobacteria among the Bacillota. They have no outer membrane and like certain other Bacillota (Clostridia), they form heat-resistant , which contain high levels of calcium and dipicolinic acid. Heliobacteria are the only Bacillota known to be phototrophic.

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Metabolism The heliobacteria are phototrophic: they convert light energy into chemical energy using a Reaction center.Heinickel and Golbeck 2007 The primary pigment involved is bacteriochlorophyll g, which is unique to the group and has a unique absorption spectrum; this gives the heliobacteria their own environmental niche.

Robert Blankenship (2026). 9781405189750, Wiley-Blackwell. ISBN 9781405189750

Phototrophy take place at the cell membrane, which does not form folds or compartments as it does in purple bacteria. Though heliobacteria are phototrophic, they can create energy without light using Fermentation, which generates significantly less energy than it could with light.

Heliobacteria are , requiring organic carbon sources, and they are exclusively anaerobic. Bacteriochlorophyll g is inactivated by the presence of oxygen, making them obligate anaerobes (they cannot survive in aerobic conditions). Heliobacteria have been found in , Hot spring, and are common in the waterlogged soils of . They are avid nitrogen fixers, so are probably important in the fertility of paddy fields. Heliobacteria are mainly terrestrial phototrophs, contrary to the multitudes of others that are aquatic, and often form mutualistic relationships with the plants near them.

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Taxonomy Heliobacteria should not be confused with Helicobacter, which is a genus of bacteria with quite different characteristics.

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI).

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See also

• List of bacterial orders
• List of bacteria genera

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Further reading

• Gest H & Favinger J L (1983) Arch Microbiol 136:11-16.
• Madigan M T (1992) In Balows et al. (eds) The Prokaryotes pp. 1981–1992 Springer New York.
• Madigan M T & Ormerod J G (1995) In Blankenship et al. (eds) Anoxygenic Photosynthetic Bacteria pp 17–30. Kluwer Academic Publishers New York.
• Ormerod J G et al. (1996) Arch Microbiol 165:226-234.
• Madigan M T, Martinko J M, Dunlap P V, Clark D P. (2009). Brock Biology of Microorganisms 12th edition, p. 453-454
• Heinnickel M & Golbeck J H (2007) Photosynthesis Research 92:35-53

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