Table 3. Overview of chemical processes and defined functional groups of microorganism.
| Functional group | Process | Redox reaction(s) | Reaction number |
|---|---|---|---|
| Sulphur and hydrogen oxidizers | Sulphide oxidation with oxygen | H2S+2O2→HSO4−+H+ HS−+2O2→HSO4− | 1a 1b |
| Sulphide oxidation with nitrate | 5H2S+8NO3−→5HSO4−+H2O+4N2+3OH− 5HS−+4H2O+8NO3−→5HSO4−+4N2+8OH− | 2a 2b | |
| Hydrogen oxidation with oxygen | 2H2+O2→2H2O | 3 | |
| Hydrogen oxidation with nitrate | 5H2+2NO3−+2H+→N2+6H2O | 4 | |
| Methane oxidizers | Methane oxidation (aerobic) | CH4+2O2→CO2+2H2O | 5 |
| Ammonium oxidizers | Ammonium oxidation | NH4++2O2→NO3−+H2O+2H+ | 6 |
| Iron oxidizers | Iron oxidation | 4Fe2++O2+10H2O→4Fe(OH)3+8H+ | 7 |
| Anaerobic methane oxidizers | Methane oxidation (anaerobic with sulphate) | CH4+SO42−+2H+→CO2+H2S+2H2O | 8 |
| Methane oxidation (anaerobic with nitrate)a | CH4+4NO3−→CO2+ 4NO2−+2H2O | 9 | |
| Methanogens | Methanogenesis | 4H2+CO2→CH4+2H2O 4H2+HCO3−+H+→CH4+3H2O | 10a 10b |
| Sulphate reducers | Sulphate reduction | 4H2+SO42−+2H+→H2S+4H2O | 11 |
Compounds in the redox reactions are in the aqueous phase, except for Fe(OH)3, which represents the mineral ferrihydrite.
a
This reaction was included in the definition of anaerobic methane oxidizers only when specified.