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Denitrifying bacteria are a diverse group of bacteria that encompass many different phyla. This group of bacteria, together with denitrifying fungi and archaea, is capable of performing denitrification as part of the nitrogen cycle. [1] Denitrification is performed by a variety of denitrifying bacteria that are widely distributed in soils and ...
Denitrification. Nitrogen cycle. Denitrification is a microbially facilitated process where nitrate (NO 3−) is reduced and ultimately produces molecular nitrogen (N 2) through a series of intermediate gaseous nitrogen oxide products. Facultative anaerobic bacteria perform denitrification as a type of respiration that reduces oxidized forms of ...
Nitrification. Nitrification is the biological oxidation of ammonia to nitrate via the intermediary nitrite. Nitrification is an important step in the nitrogen cycle in soil. The process of complete nitrification may occur through separate organisms [1] or entirely within one organism, as in comammox bacteria.
Denitrification is the reduction of nitrates back into nitrogen gas (N. 2), completing the nitrogen cycle. This process is performed by bacterial species such as Pseudomonas and Paracoccus, under anaerobic conditions. They use the nitrate as an electron acceptor in the place of oxygen during respiration.
Nitrifying bacteria are chemolithotrophic organisms that include species of genera such as Nitrosomonas, Nitrosococcus, Nitrobacter, Nitrospina, Nitrospira and Nitrococcus. These bacteria get their energy from the oxidation of inorganic nitrogen compounds. [1] Types include ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB).
Assimilatory nitrate reductase is an enzyme of the assimilative metabolism involved in reduction of nitrate to nitrite. The nitrite is immediately reduced to ammonia (probably via hydroxylamine) by the activity of nitrite reductase. The term assimilatory refers to the fact that the product of the enzymatic activity remains in the organism.
Many facultative anaerobes use denitrification because nitrate, like oxygen, has a high reduction potential. Many denitrifying bacteria can also use ferric iron (Fe 3+) and some organic electron acceptors. Denitrification involves the stepwise reduction of nitrate to nitrite (NO − 2), nitric oxide (NO), nitrous oxide (N 2 O), and dinitrogen (N
Regulation. Nitrate reductase (NR) is regulated at the transcriptional and translational levels induced by light, nitrate, and possibly a negative feedback mechanism. First, nitrate assimilation is initiated by the uptake of nitrate from the root system, reduced to nitrite by nitrate reductase, and then nitrite is reduced to ammonia by nitrite ...