Nitrosomonas
Nitrosomonas
Nitrosomonas is a genus of Gram-negative, chemolithoautotrophic bacteria that play a crucial role in the global nitrogen cycle. They derive their energy by oxidizing ammonia into nitrite, a process known as nitritation. These bacteria are obligate aerobes and utilize carbon dioxide as their primary carbon source. They are found ubiquitously in soil, freshwater, marine environments, and especially in wastewater treatment plants.
Details
Identification
Rod-shaped, ellipsoidal, or spherical cells; often motile with polar flagella; sometimes forming cell aggregates.
Social behavior
Formation of biofilms and cell aggregates to optimize metabolism and provide protection.
Diet
Uses ammonia (NH3) as an energy source and inorganic carbon (CO2) for cell synthesis.
Overwintering
Dormant stages or reduced metabolic activity at low temperatures.
Ecology
Ecological role
Primary nitrifier; converts ammonia (toxic to fish) into nitrite, enabling further degradation by Nitrobacter.
Natural predators
Bacteriovorous protozoa (unicellular organisms) and bacteriophages.
Competitor species
Other ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA).
Ecosystem service
Purification of water bodies; nitrogen cycling in soil; key role in wastewater treatment.
Threats
Toxic inhibitors such as heavy metals, pesticides, or sudden pH fluctuations.
Scientific profile
Profile
Habitat
Ubiquitously distributed in soils, freshwater, marine habitats, and especially in wastewater treatment plants (activated sludge). Prefers sites with high availability of ammonium and carbonates.
Ecological role
Key organism in the global nitrogen cycle. Nitrosomonas performs the first, rate-limiting step of nitrification (ammonia oxidation), providing the basis for subsequent nitrate formation by Nitrobacter.