Nitrifier

Nitrifizierer even nitrificants or Salpeterbakterien called, are gram-negative aerobic bacteria that behind the process of nitrification are and thus the most important organisms in the nitrogen cycle include. On the basis of their metabolism, a distinction is made between ammonia oxidizers (AOB, also nitrite bacteria), which oxidize ammonia to nitrite , and nitrite oxidizers (NOB, also nitrate bacteria), which oxidize nitrite ions to nitrate . The generic name of ammonia oxidizers always begins with " Nitroso -", that of nitrite oxidizers with " Nitro -". In 2015, the complete oxidation of ammonia to nitrate was discovered in the genus Nitrospira . These bacteria catalyze both nitrification steps and are therefore referred to as complete ammonia oxidizers or comammox bacteria.

Genera

Ammonia oxidizer

Nitrite oxidizer

proof

In addition to the cultivation of bacteria, which takes a very long time, fluorescence in situ hybridization (FISH) using a targeted rRNA search for the detection of nitrifiers in samples from sewage treatment plants and the search for functional genes using functional gene arrays have proven successful (FGA), i.e. a specific variant of the DNA microarray , for soil and sediment samples. FISH is difficult to use for soil or sediment samples due to its high level of autofluorescence and lower ribosome content.

AmoA , one of the three coding genes for the protein ammonia monooxygenase (AMO), serves as a marker for functional gene arrays in ammonia oxidizers . Rotthauwe et al. cite the advantages of detection using amoA that it allows great specificity and the fine-scale differentiation of closely related populations, and that amoA is not used to examine a phylogenetic but a functional characteristic.

Web links

Biodiversity and ecophysiology of nitrifying bacterial communities ( Memento from December 7, 2014 in the Internet Archive ) Division of Microbial Ecology, University of Vienna (English)

Individual evidence

↑ Holger Daims et al .: Complete nitrification by Nitrospira bacteria . Nature 528, pp. 504-509, December 2015
^ DY Sorokin, S. Lücker, D. Vejmelkova, NA Kostrikina, R. Kleerebezem, WI Rijpstra, JS Damsté, D. Le Paslier, G. Muyzer, M. Wagner, MC van Loosdrecht, H. Daims: Nitrification expanded: discovery , physiology and genomics of a nitrite-oxidizing bacterium from the phylum Chloroflexi. In: The ISME journal. Volume 6, number 12, December 2012, pp. 2245-2256, doi : 10.1038 / ismej.2012.70 , PMID 22763649 , PMC 3504966 (free full text).
↑ Biodiversity and ecophysiology of ammonia-oxidizing bacteria ( Memento of December 8, 2014 in the Internet Archive )
↑ Rotthauwe et al .: The ammonia monooxygenase structural gene amoA as a functional marker: molecular fine-scale analysis of natural ammonia-oxidizing populations . In: Applied and Environmental Microbiology , Vol. 63, No. 12, December 1997, pp. 4702-4712.

[1] Holger Daims et al .: Complete nitrification by Nitrospira bacteria . Nature 528, pp. 504-509, December 2015

[2] DY Sorokin, S. Lücker, D. Vejmelkova, NA Kostrikina, R. Kleerebezem, WI Rijpstra, JS Damsté, D. Le Paslier, G. Muyzer, M. Wagner, MC van Loosdrecht, H. Daims: Nitrification expanded: discovery , physiology and genomics of a nitrite-oxidizing bacterium from the phylum Chloroflexi. In: The ISME journal. Volume 6, number 12, December 2012, pp. 2245-2256, doi : 10.1038 / ismej.2012.70 , PMID 22763649 , PMC 3504966 (free full text).

[3] Biodiversity and ecophysiology of ammonia-oxidizing bacteria ( Memento of December 8, 2014 in the Internet Archive )

[4] Rotthauwe et al .: The ammonia monooxygenase structural gene amoA as a functional marker: molecular fine-scale analysis of natural ammonia-oxidizing populations . In: Applied and Environmental Microbiology , Vol. 63, No. 12, December 1997, pp. 4702-4712.