A New Perspective on Microbes Formerly Known as Nitrite-Oxidizing Bacteria.
Nitrite-oxidizing bacteria (NOB) catalyze the second step of nitrification, nitrite oxidation to nitrate, which is an important process of the biogeochemical nitrogen cycle. NOB were traditionally perceived as physiologically restricted organisms and were less intensively studied than other nitrogen-cycling microorganisms. This picture is in contrast to new discoveries of an unexpected high diversity of mostly uncultured NOB and a great physiological versatility, which includes complex microbe-microbe interactions and lifestyles outside the nitrogen cycle. Most surprisingly, close relatives to NOB perform complete nitrification (ammonia oxidation to nitrate) and this finding will have far-reaching implications for nitrification research. We review recent work that has changed our perspective on NOB and provides a new basis for future studies on these enigmatic organisms.
Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Research Network Chemistry meets Microbiology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria. Electronic address: daims@microbial-ecology.net.
Holger
H
Daims
Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
Sebastian
S
Lücker
Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Research Network Chemistry meets Microbiology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
Michael
M
Wagner
D000641:Ammonia / Q000737:chemistry; D058465:Nitrification / Q000502:physiology*; D009572:Nitrite Reductases / Q000235:genetics / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism*; D009576:Nitrobacter / Q000235:genetics / Q000378:metabolism*; D009606:Nitrosomonas / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D062065:Wastewater / Q000382:microbiology; D018508:Water Purification
D000641:Ammonia; D009572:Nitrite Reductases; D009573:Nitrites; D010088:Oxidoreductases; D062065:Wastewater; C021401:hydroxylamine dehydrogenase; C045582:ammonia monooxygenase
ammonia-oxidizing microorganisms; comammox.; nitrification; nitrite-oxidizing bacteria; reciprocal feeding