Microbial oxidation of sulfur

Reactions of oxidation of sulfide to sulfate and elemental sulfur (incorrectly balanced). The electrons (e−) liberated from these oxidation reactions, which release chemical energy, are then used to fix carbon into organic molecules. The elements that become oxidized are shown in pink, those that become reduced in blue, and the electrons in purple.

Microbial oxidation of sulfur is the oxidation of sulfur by microorganisms to build their structural components. The oxidation of inorganic compounds is the strategy primarily used by chemolithotrophic microorganisms to obtain energy to survive, grow and reproduce. Some inorganic forms of reduced sulfur, mainly sulfide (H2S/HS−) and elemental sulfur (S0), can be oxidized by chemolithotrophic sulfur-oxidizing prokaryotes, usually coupled to the reduction of oxygen (O2) or nitrate (NO3−).[1][2] Anaerobic sulfur oxidizers include photolithoautotrophs that obtain their energy from sunlight, hydrogen from sulfide, and carbon from carbon dioxide (CO2).

Most of the sulfur oxidizers are autotrophs that can use reduced sulfur species as electron donors for CO2 fixation. The microbial oxidation of sulfur is an important link in the biogeochemical cycling of sulfur in environments hosting both abundant reduced sulfur species and low concentrations of oxygen, such as marine sediments, oxygen minimum zones (OMZs) and hydrothermal systems.[3]

  1. ^ Fry B, Ruf W, Gest H, Hayes JM (1988). "Sulfur isotope effects associated with oxidation of sulfide by O2 in aqueous solution". Isotope Geoscience. 73 (3): 205–10. Bibcode:1988CGIGS..73..205F. doi:10.1016/0168-9622(88)90001-2. PMID 11538336.
  2. ^ Burgin AJ, Hamilton SK (2008). "NO3−-Driven SO42− Production in Freshwater Ecosystems: Implications for N and S Cycling". Ecosystems. 11 (6): 908–922. Bibcode:2008Ecosy..11..908B. doi:10.1007/s10021-008-9169-5. S2CID 28390566.
  3. ^ Fike DA, Bradley AS, Leavitt WD (2016). Geomicrobiology of sulfur (Sixth ed.). Ehrlich's Geomicrobiology.