Which bacteria are responsible for converting nitrite (NO2) to nitrate (NO3)?

The conversion of nitrite (NO2) to nitrate (NO3) is primarily carried out by bacteria known as Nitrobacter. This process is part of the nitrogen cycle, specifically within the stage of nitrification. During nitrification, ammonia (NH3) is first oxidized to nitrite by bacteria such as Nitrosomonas, and then Nitrobacter takes over to convert that nitrite into nitrate.

Nitrobacter plays a crucial role in maintaining the nitrogen balance in aquatic ecosystems and wastewater treatment facilities, as it helps to remove potentially toxic nitrite, converting it into the less harmful nitrate form, which can then be utilized by plants or further processed in biological systems.

Other types of bacteria, such as Escherichia coli, Pseudomonas, and Staphylococcus, have different metabolic roles or functions that do not include this specific conversion of nitrite to nitrate and are not involved in the nitrification process in the way that Nitrobacter is.