Desulfococcus

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A Microbial Biorealm page on the genus Desulfococcus

(A) DAPI staining (B) FISH for the Desulfosarcina-Desulfococcus group from [Ravenschlag et al. 2000]

Classification

Higher order taxa:

Bacteria; Proteobacteria; delta/epsilon subdivisions; Deltaproteobacteria; Desulfobacterales; Desulfobacteraceae

Species:

NCBI: Taxonomy Genome: Desulfococcus oleovorans Hxd3 '

Desulfococcus biacutus, Desulfococcus multivorans, Desulfococcus oleovorans, Desulfococcus sp. DSM 8541

Description and Significance

Desulfococcus group is cultivated bacteria as well as Desulfosarcina. They can completely oxidize acetate by using sulfate as electron acceptor under anoxic condition. They are involved in Chemoautotrophs, anaerobic, thermophilic and mesophilic bacteria. In coastal marine sediments, over 50% of carbon is decomposed by sulfate-reducing bacteria including Desulfococcus. Also, they play an important role in the cycling of sulfur compounds of in sea water(Das et al 2006).

Genome Structure

The genome of Desulfococcus oleovorans is completely sequenced. Desulfococcus oleovorans is a sulfate-reducing δ-proteobacterium. The G+C content of the 16S ribosomal DNA gene of Desulfococcus oleovorans is 63%(So and Young 1999). Strain Hxd3 of Desulfococcus oleoborans was isolated from an oil tank. Desulfococcus oleoborans can use alkanes from C12 to C20 due to strain Hxd3, they have best growth rate in the range form C15 to C18.

Cell Structure and Metabolism

Desulfococcus are sphere shape bacteria. Desulfococcus oleovorans can use alkanes from C12 to C20, 1-hexadecene, 1-hexadecanol, 2-hexadecanol, palmitate and stearate as electron donors and sulfate as terminal electron acceptor for the growth(Aeckersberg et al., 1991). This indicates that Desulfococcus oleovorans play an crucial role in the accumulation of sulfide(Rueter et al., 1994). Also, Desulfococcus have the capability of detoxifying mercury compounds. Desulfococcus can methylate mercury(Macalady et al 2000)

Ecology

Desulfococcus groups are one of the most active population in coastal sediments. In general, sulfate-reducing bacteria group are considered as obligate anaerobes, but some SRB can survive in the presence of oxygen. For example, Duslfobulbus, Desulfobacter and Desulfotomaculum species are predominant in the lower part of sediments, while the Desulfococcus and Deuslfovibrio groups predominantly occupy in the upper part of the photo-oxic zone (Risatti et al, 1994). However, Desulfococcus use energy only for maintenancein oxic condition. They can grow only at anoxic condition so that they are considered as anaerobic bacteria.

References

1. Ravenschlag, K. Sahm, K. Knoblauch, C. Jørgensen, , B.B., and Amann, , R. ( 2000) Community structure, cellular rRNA content, and activity of sulfate-reducing bacteria in marine Arctic sediments. Appl Environ Microbiol 66: 3592– 3602.

2. Surajit Das, P. S. Lyla and S. Ajmal(2006) Marine microbial diversity and ecology: importance and future perspectives., CURRENT SCIENCE, VOL. 90, NO. 10

3. Chi Ming So and L. Y. Young.,(1999) Isolation and Characterization of a Sulfate-Reducing Bacterium That Anaerobically Degrades Alkanes., Appl Environ Microbiol., 65(7): 2969–2976

4. Aeckersberg F, Bak F, Widdel F (1991) Anaerobic oxidation of saturated hydrocarbons to CO2 by a new type of sulfate-reducing bacterium. Arch Microbiol 156:5–14

5. Macalady,J.L., Mack,E.E., Nelson,D.C., and Scow,K.M. ( 2000) Sediment microbial community structure and mercury methylation in mercury-polluted Clear Lake, California. Appl Environ Microbiol 66: 1479– 1488.

6.Risatti, J.B., Capman, W.C., and Stahl, D.A. ( 1994 ) Community structure of a microbial mat: the phylogenetic perspective. Proc Natl Acad Sci USA 91: 10173– 10177.

7.NCBI Taxonomy browser

8. NCBI Gene project

Edited by student of Kate Scow