Desulfovibrio

Taxonomy

•Domain: Eubacteria

•Phylum: Proteobacteria (purple bacteria)

•Class: δ-Proteobacteria

•Order: Desulfavibrionales

•Family: Desulfovibrionaceae

•Genus: Desulfovibrio

Representative specieswww.deskuenvis.nic.in

D. vulgaris

http://n-equals-one.com

D. desulfuricans

Morphology

•Colonies▫Pink or peach colored

•Cells▫Dimensions: 2.5-10 µm long × 0.5-1.5

µm wide

▫Gram negative

▫Shape: Curved rods (vibrio)

Physiology

•Non-spore forming•Mesophilic•Motility

▫Motile

▫Polar flagella Mono- or lophotrichous

•Produces black precipitate throughout SIM tube

Metabolism

•Either Chemoorganoheterotrophic or Chemolithoautotrophic

•Strict anaerobes▫ some strains are shown to be aerotolerant

•Anaerobic Respiration or Fermentation•Carbon sources:

▫acetate, formate, lactate, pyruvate, CO2,

other organic compounds (eg. crude oil components)

Metabolism

•Electron donors:▫formate, lactate, pyruvate, acetate, iron, H2

•Electron acceptors:▫SO4

2-, other oxidized sulfur species, oxidized

nitrogen species (eg. nitrate, nitrite)•Major products of metabolism:

▫H2S

Global Sulfur Cycle

Habitat/Environmental adaptation

•Found in organic-rich anoxic environments:▫Mud, sediment of polluted lakes

▫Sewage lagoons and methane digesters (bioreactors)

▫Waterlogged soils

▫Oil fields

Bioremediation

•Sewage, industrial wastewater, and mine drainage contain toxic heavy metals (Cr, Cu, Mn, Zn)

•H2S produced by Desulfovibrio species removes heavy metals by precipitation

•Used in toxic waste cleanup

Experiment• Measured the capacity of Desulfovibrio

desulfuricans to precipitate heavy metals from wastewater

• Organic dye production wastewater treated for 6 days with Desulfovibrio desulfuricans in an anaerobic bioreactor had reduced heavy metal concentrations:

▫ [Zn2+] reduced by 97.53%

▫ [Ni2+] reduced by 98.96%

▫ [Cu2+] reduced by 85.42%

Negative effects

•High [H2S] can kill local flora

•Rotten egg smell

•Corrosion of iron pipelines by reducing iron metal:

Fe(s) Fe2+(aq)

Infections

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC156571/

Question

What role does sulfate play in Desulfovibrio metabolism?

A. sulfur source

B. electron donor

C. electron acceptor

D. carbon source

ReferencesCabrera, G., Pérez, R., Gomez, J. M., Abalos, A., & Cantero, D. (2006). Toxic effects of dissolved heavy metals on Desulfovibrio vulgaris and Desulfovibrio sp. strains. Journal of hazardous materials, 135(1), 40-46.

Desulfovibrio. (2006). In Dictionary of microbiology & molecular biology. Retrieved from http://proxy.iusb.edu:2443/login?qurl=http%3A%2F%2Fproxy.iusb.edu%3A3194%2Fcontent%2Fentry%2Fwileymicrob%2Fdesulfovibrio%2F0

Kosinska, K., Miskiewicz, T. (2012) Precipitation of heavy metals from industrial wastewater by Desulfovibrio desulfuricans. Environment Protection Engineering, 38, 51-60.

Voordouw, G. (1995). The genus Desulfovibrio: the centennial. Applied and environmental microbiology, 61(8), 2813.

Wiley, J.M., Sherwood, L.M., Woolverton C.J. (2014). Prescott’s Microbiology. New York: McGraw-Hill.

Magot M et al. (2004). Int. J. Syst. Evol. Microbiol. 54:1693-1697.