Sulfate-reducing microorganism

[1][2] Therefore, these sulfidogenic microorganisms "breathe" sulfate rather than molecular oxygen (O2), which is the terminal electron acceptor reduced to water (H2O) in aerobic respiration.

Sulfate-reducing microorganisms can be traced back to 3.5 billion years ago and are considered to be among the oldest forms of microbes, having contributed to the sulfur cycle soon after life emerged on Earth.

[7] In addition, there are sulfate-reducing microorganisms that can also reduce other electron acceptors, such as fumarate, nitrate (NO−3), nitrite (NO−2), ferric iron (Fe3+), and dimethyl sulfoxide (DMSO).

The organotrophs oxidize organic compounds, such as carbohydrates, organic acids (such as formate, lactate, acetate, propionate, and butyrate), alcohols (methanol and ethanol), aliphatic hydrocarbons (including methane), and aromatic hydrocarbons (benzene, toluene, ethylbenzene, and xylene).

[5] Sulfate is also found in more extreme environments such as hydrothermal vents, acid mine drainage sites, oil fields, and the deep subsurface,[11] including the world's oldest isolated ground water.

[15] Sulfate-reducing bacteria also generate neurotoxic methylmercury as a byproduct of their metabolism, through methylation of inorganic mercury present in their surroundings.

[3] Some sulfate-reducing microorganisms play a role in the anaerobic oxidation of methane:[3] An important fraction of the methane formed by methanogens below the seabed is oxidized by sulfate-reducing microorganisms in the transition zone separating the methanogenesis from the sulfate reduction activity in the sediments.

Biocide compounds are often added to water to inhibit the microbial activity of sulfate-reducing microorganisms, in order to but not limited to, avoid anaerobic methane oxidation and the generation of hydrogen sulfide, ultimately resulting in minimizing potential production loss.

[1] The second largest group of sulfate-reducing bacteria is found among the Bacillota, including the genera Desulfotomaculum, Desulfosporomusa, and Desulfosporosinus.

In July 2019, a scientific study of Kidd Mine in Canada discovered sulfate-reducing microorganisms living 7,900 feet (2,400 m) below the surface.

The sulfate reducers discovered in Kidd Mine are lithotrophs, obtaining their energy by oxidizing minerals such as pyrite rather than organic compounds.

Desulfovibrio vulgaris is the best-studied sulfate-reducing microorganism species; the bar in the upper right is 0.5 micrometre long.
Sludge from a pond; the black color is due to metal sulfides that result from the action of sulfate-reducing microorganisms.
Overview of the three key enzymatic steps of the dissimilatory sulfate reduction pathway. Enzymes: sat and atps respectively stand for sulfate adenylyltransferase and ATP sulfurylase (EC 2.7.7.4); apr and aps are both used to adenosine-5'-phosphosulfate reductase (EC 1.8.4.8); and dsr is the dissimilatory (bi)sulfite reductase (EC 1.8.99.5);