Desulfobulbus propionicus (lat.) Is a gram - negative chemo - organotrophic bacterium of the delta proteobacteria class [1] [2] , a type species of the genus Desulfobulbus [3] . Three strains of this species are known, designated 1pr3 T , 2pr4 and 3pr10. This is the first bacterium isolated in pure , capable of disproportioning elemental sulfur to sulfate and sulfide [4] .
| Desulfobulbus propionicus | |||||||||||||||
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Desulfobulbus propionicus Widdel 1981 | |||||||||||||||
Content
Name Etymology
The generic name Desulfobulbus is derived from lat. de- - from, lat. sulfur - sulfur and lat. bulbus - onion, that is literally "onion-like reducing agent of sulfur." The species epithet propionicus is given for the substance serving as the electron donor for this organism, propionate [2] .
Discovery History
Species Desulfobulbus propionicus was named Friedrich Widdel in 1981 [5] , described by him and Norbert Pfenning in 1982. The species was isolated from samples of anaerobic mud from village ditches, ponds and sea terraces of silty soil in Germany . All three strains were isolated using method with shaking on a basal medium with the addition of sulfate, mineral salts, iron , trace elements , bicarbonate , sulfide and several vitamins [2] .
Description
Morphology
Desulfobulbus propionicus is a gram-negative bacterium, having the form from ellipsoidal to lemon-shaped. The length of the cells is 1.0-1.3 microns , the width is 1.8-2.0 microns [1] . Three strains differ in shape, mobility and the presence of fimbriae (see table) [2] .
| Strain | The form | Mobility | Fimbria |
|---|---|---|---|
| 1pr3 T | Lemon-shaped | Motionless | there is |
| 2pr4 | Ovoid | Single polar flagellum | Not |
| 3pr10 | Ellipsoidal | Single polar flagellum | Not |
Metabolism
Desulfobulbus propionicus - anaerobic chemoorganotroph. She uses the to ferment 3 moles of pyruvate to 2 moles of acetate and 1 mole of propionate. This species uses propionate, lactate , pyruvate and environmental alcohols not only as an electron donor, but also as a carbon source. Hydrogen is used only as an electron donor in the presence of carbon dioxide and acetate. As the name implies, Desulfobulbus propionicus reduces sulfate, sulfite and thiosulfate to hydrogen sulfide , but cannot restore elemental sulfur, malate and fumarate . In the absence of sulfate, the bacterium ferments ethanol to propionate and acetate. In the absence of an electron acceptor, D. propionicus carries out a disproportionation reaction of elemental sulfur and water to sulfate and sulfide. Strains 1pr3 T and 3pr10 can grow on minimal medium only with the addition of vitamin 4-aminobenzoic acid , while 2pr4 does not have such additional requirements. In addition, this is the only strain of the three that can grow on butyrate as an electron donor and carbon source, although more slowly than on other substrates [1] [2] .
Genome
The genome is sequenced in only one strain of Desulfobulbus propionicus , 1pr3 T. It was sequenced in 2011. The genome of strain 1pr3 T contains 3851869 base pairs and has a GC composition of 58.93%. 3408 genes are predicted in the genome, of which 3351 encode proteins . The genome contains 57 genes encoding only RNA , and two rRNA operons . Moreover, it contains 68 pseudogenes that make up 2% of the genome [1] .
Distribution and Ecology
Desulfobulbus propionicus inhabits anaerobic freshwater and marine bottom sediments [1] . The table below shows the distribution and habitat of strains of Desulfobulbus propionicus .
| Strain | Geographical localization [2] | Habitat [2] |
|---|---|---|
| 1pr3 T | Lindhort, Germany | Mud from the ditch |
| 2pr4 | Hanover , Germany | Mud from the pond |
| 3pr10 | , Germany ( North Sea ) | Sea mud |
Three strains differ in temperature range, optimal temperature, pH range, optimal pH, and the required concentration of NaCl [1] [2] . These differences are reflected in the table:
| Strain | Interval temperature Β° C [2] | Optimal temperature, Β° C [2] | PH range [2] | Optimum pH [2] | Necessary NaCl concentration, g / l [2] |
|---|---|---|---|---|---|
| 1pr3 T | 10β43 | 39 | 6.0-8.6 | 7.2 | less than 15 |
| 2pr4 | 10β36 | thirty | 6.6-8.1 | 7.2 | less than 15 |
| 3pr10 | 15β36 | 29th | 6.6-8.1 | 7.4 | more than 15 |
Taxonomy
Species Desulfobulbus propionicus includes three strains: 1pr3 T , 2pr4 and 3pr10. All strains are gram-negative sulfate reducers, which are required to grow exclusively on pyruvate or lactate without any additional sources of carbon and electrons. Strain 1pr3 T is characterized by its ability to reduce sulfite and thiosulfate to hydrogen sulfide, nitrate to ammonium , in addition, it has cytochromes and c . In addition, this strain differs from the other two in shape (the pointed ends of 1pr3 T instead of those of the other strains rounded), mobility (1pr3 T is immobile, and the bacteria of the other two strains have a flagellum), as well as the presence of fimbriae (two other strains of fimbria no) [2] .
According to the analysis of 16S rRNA , within the genus species Desulfobulbus propionicus is closest to the species Desulfobulbus elongatus (96.9% sequence identity), a slightly more distant relative is Desulfobulbus rhabdoformis , and the species Desulfobulbus mediterraneus and Desulfobulbus japonicas are approximately identical the third closest degree of kinship [1] .
Application
Desulfobulbus propionicus can serve as a biocatalyst in microbial electrosynthesis . Microbial electrosynthesis is the use of electrons by microorganisms to restore carbon dioxide to organic molecules. When Desulfobulbus propionicus is present on the anode , it oxidizes elemental sulfur to sulfate, which creates free electrons for electrosynthesis. Free electrons move to the body located at the cathode. A microbe sitting on the cathode uses the energy of electrons transferred from Desulfobulbus propionicus to restore carbon dioxide to organic molecules (such as acetate). The use of microbial electrosynthesis can be useful for the chemical industry and energy [6] .
Notes
- β 1 2 3 4 5 6 7 Pagani I. , Lapidus A. , Nolan M. , Lucas S. , Hammon N. , Deshpande S. , Cheng JF , Chertkov O. , Davenport K. , Tapia R. , Han C. , Goodwin L. , Pitluck S. , Liolios K. , Mavromatis K. , Ivanova N. , Mikhailova N. , Pati A. , Chen A. , Palaniappan K. , Land M. , Hauser L. , Chang YJ , Jeffries CD , Detter JC , Brambilla E. , Kannan KP , Djao OD , Rohde M. , Pukall R. , Spring S. , GΓΆker M. , Sikorski J. , Woyke T. , Bristow J. , Eisen JA , Markowitz V. , Hugenholtz P. , Kyrpides NC , Klenk HP Complete genome sequence of Desulfobulbus propionicus type strain (1pr3). (English) // Standards in genomic sciences. - 2011. - Vol. 4, no. 1 . - P. 100-110. - DOI : 10.4056 / sigs.1613929 . - PMID 21475592 .
- β 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Widdel Friedrich , Pfennig Norbert. Studies on dissimilatory sulfate-reducing bacteria that decompose fatty acids II. Incomplete oxidation of propionate by Desulfobulbus propionicus gen. nov., sp. nov. // Archives of Microbiology. - 1982. - June ( t. 131 , No. 4 ). - S. 360β365 . - ISSN 0302-8933 . - DOI : 10.1007 / BF00411187 .
- β Genus Desulfobulbus . LPSN . (Retrieved October 5, 2016) .
- β Lovley DR , Phillips EJ Novel processes for anaerobic sulfate production from elemental sulfur by sulfate-reducing bacteria. (English) // Applied and environmental microbiology. - 1994. - Vol. 60, no. 7 . - P. 2394-2399. - PMID 16349323 .
- β Validation of the Publication of New Names and New Combinations Previously Effectively Published Outside the IJSB: List No. 7 // International Journal of Systematic Bacteriology. - 1981. - July 1 ( t. 31 , No. 3 ). - S. 382-383 . - ISSN 0020-7713 . - DOI : 10.1099 / 00207713-31-3-382 .
- β Gong Y. , Ebrahim A. , Feist AM , Embree M. , Zhang T. , Lovley D. , Zengler K. Sulfide-driven microbial electrosynthesis. (English) // Environmental science & technology. - 2013 .-- Vol. 47, no. 1 . - P. 568-573. - DOI : 10.1021 / es303837j . - PMID 23252645 .