Desulfurellaceae

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Desulfurellaceae
Systematics
Classification : Creature
Domain : Bacteria (bacteria)
Department : Proteobacteria
Class : Deltaproteobacteria
Order : Desulfurellales
Family : Desulfurellaceae
Scientific name of the  order
Desulfurellales
Kuever et al. 2006
Scientific name of the  family
Desulfurellaceae
Kuever et al. 2006

The Desulfurellaceae form a family within the Deltaproteobacteria and are the few members of the order Desulfurellales . Like all proteobacteria, the species are gram-negative . The cells are rod-shaped and usually motile by a single polar flagella. These are anaerobic , chemoorganotrophic or chemolithoautotrophic bacteria. The species of Desulfurellaceae are sulfur reducers, in their metabolism they convert elemental sulfur into hydrogen sulfide . Another feature is the absence of cytochromes , although respiratory metabolism is carried out.

ecology

All species are thermophilic , the best growth occurs at temperatures between 50 and 60 ° C. Habitats are sea water and geothermally heated, sulphurous fresh water. Due to the reduction of sulfur, polysulfides or thiosulfate to hydrogen sulfide , they are important for the sulfur cycle .

metabolism

The species of Desulfurellaceae are among the sulfur-reducing bacteria, also known as sulfur breathers. It is an anaerobic respiratory metabolism. Instead of oxygen in aerobic respiration, elemental sulfur or polysulphides serve as electron acceptors . Electron donors are simple organic compounds, they are completely oxidized to carbon dioxide by the citric acid cycle. The sulfur compounds are reduced to sulfide or hydrogen sulfide . Desulfurella propionica also reduces thiosulfate.

This metabolic pathway largely corresponds to desulfurization , except that only elemental sulfur (including thiosulfate and polysulfide) is used. In desulphurication, also known as dissimilatory sulphate reduction, sulphate is mainly used, in various types sulphite, thiosulphite and also elemental sulfur are used as acceptors. The end product is also hydrogen sulfide. In contrast to the sulfate-reducing bacteria (English: Sulfate-Reducing Prokaryotes), the Desulfurellaceae therefore speak of sulfur-reducing bacteria (English: Sulfur-Reducing Prokaryotes). The prefix desulfur refers to the elemental sulfur (sulfur). Desulfurella multipotens is chemolithoautotrophic, it only needs CO 2 , H 2 and elemental sulfur to grow . If available, it also uses organic compounds such as acetate , pyruvate , butyrate and saturated fatty acids . The organic compounds used as electron donors are mostly completely oxidized to CO 2 .

Hippea maritima is chemolithotrophic, it uses H 2 and sulfur, but needs organic substances as electron donors and carbon source. Organic compounds used are e.g. B. acetate, pyruvate and saturated fatty acids.

Some species also have the ability to ferment as an energy metabolic pathway.

Systematics

The family consists of the following genera and species:

  • Desulfurella Bonch-Osmolovskaya et al. 1993
    • Desulfurella acetivorans Bonch-Osmolovskaya et al. 1993
    • Desulfurella kamchatkensis Miroshnichenko et al. 1998
    • Desulfurella multipotens Miroshnichenko et al. 1996
    • Desulfurella propionica Miroshnichenko et al. 1998
  • Hippea Miroshnichenko et al. 1999
    • Hippea maritima Miroshnichenko et al. 1999

swell

  1. ↑ National Center for Biotechnology Information (NCBI) as of November 26, 2012

literature

  • Michael T. Madigan, John M. Martinko, Jack Parker: Brock - Microbiology . 11th edition. Pearson Studium, Munich 2006, ISBN 3-8274-0566-1
  • George M. Garrity: Bergey's manual of systematic bacteriology . 2nd Edition. Springer, New York, 2005, Vol. 2: The Proteobacteria Part C: The Alpha-, Beta-, Delta-, and Epsilonproteabacteria ISBN 0-387-24145-0