121:
453:), which could be damaging to human health and ecological processes if left untreated. Many physical, chemical, and biological methods have been used to remove the nitrogenous compounds and purify polluted waters. The process and methods vary, but it generally involves converting ammonium to nitrate via the nitrification process with ammonium oxidizing bacteria (AOB, NH
469:), and finally to nitrogen gas via denitrification. One example of this is ammonia-oxidizing bacteria which have a metabolic feature that, in combination with other nitrogen-cycling metabolic activities, such as nitrite oxidation and denitrification, remove nitrogen from wastewater in activated sludge. Since denitrifying bacteria are
391:-like bacteria carrying out the methane oxidation because their abundance peaked at the same depth where the methane and nitrate profiles met. This n-damo process is significant because it aids in decreasing methane emissions from deep freshwater bodies and it aids in turning nitrates into nitrogen gas, reducing excess nitrates.
315:. Removing methane is widely considered to be beneficial to the environment, although the extent of the role that denitrification plays in the global flux of methane is not well understood. Anaerobic denitrification as a mechanism has been shown to be capable of removing the excess nitrate caused by fertilizer runoff, even in
404:
The process of denitrification can lower the fertility of soil as nitrogen, a growth-limiting factor, is removed from the soil and lost to the atmosphere. This loss of nitrogen to the atmosphere can eventually be regained via introduced nutrients, as part of the nitrogen cycle. Some nitrogen may also
330:
contamination in the
Antarctic, as well as a 2016 study which successfully increased the rates of denitrification by altering the environment housing the bacteria. Denitrifying bacteria are said to be high quality bioremediators because of their adaptability to a variety of different environments, as
135:
to denitrification when oxygen as an available terminal electron acceptor (TEA) runs out. This forces the organism to use nitrate to be used as a TEA. Because the diversity of denitrifying bacteria is so large, this group can thrive in a wide range of habitats including some extreme environments such
366:
found that anaerobic methane oxidation coupled to denitrification β also referred to as nitrate/nitrite-dependent anaerobic methane oxidation (n-damo) β is a dominant sink of methane in deep lakes. For a long time, it was considered that the mitigation of methane emissions was only due to aerobic
195:
The result is one molecule of nitrogen and six molecules of water. Denitrifying bacteria are a part of the N cycle, and consists of sending the N back into the atmosphere. The reaction above is the overall half reaction of the process of denitrification. The reaction can be further divided into
473:, an organic carbon source is supplied to the bacteria in an anoxic basin. With no available oxygen, denitrifying bacteria use the redox of nitrate to oxidize the carbon. This leads to the creation of nitrogen gas from nitrate, which then bubbles up out of the wastewater.
295:
found to oxidize methane independently. This process uses the excess electrons from methane oxidation to reduce nitrates, effectively removing both fixed nitrogen and methane from aquatic systems in habitats ranging from sediment to peat bogs to stratified water columns.
659:
Ettwig, Katharina F.; Shima, Seigo; van de Pas-Schoonen, Katinka T.; Kahnt, JΓΆrg; Medema, Marnix H.; op den Camp, Huub J. M.; Jetten, Mike S. M.; Strous, Marc (November 2008). "Denitrifying bacteria anaerobically oxidize methane in the absence of
Archaea".
799:
Raghoebarsing, Ashna A.; Pol, Arjan; van de Pas-Schoonen, Katinka T.; Smolders, Alfons J. P.; Ettwig, Katharina F.; Rijpstra, W. Irene C.; Schouten, Stefan; DamstΓ©, Jaap S. Sinninghe; Op den Camp, Huub J. M.; Jetten, Mike S. M.; Strous, Marc (April 2006).
1248:
Ni, Bing-Jie; Pan, Yuting; Guo, Jianhua; Virdis, Bernardino; Hu, Shihu; Chen, Xueming; Yuan, Zhiguo (2016), Moura, Isabel; Moura, JosΓ© J G; Pauleta, Sofia R; Maia, Luisa B (eds.), "Chapter 16. Denitrification
Processes for Wastewater Treatment",
38:. Denitrification is performed by a variety of denitrifying bacteria that are widely distributed in soils and sediments and that use oxidized nitrogen compounds such as nitrate and nitrite in the absence of oxygen as a terminal
386:
The results from the study on Lake
Constance found that nitrate was depleted in the water at the same depth as methane, which suggests that methane oxidation was coupled to denitrification. It could be inferred that it was
156:), using nitrate reductase (Nar or Nap), nitrite reductase (Nir), nitric oxide reductase (Nor), and nitrous oxide reductase (Nos). Phylogenetic analysis revealed that aerobic denitrifiers mainly belong to Ξ±-, Ξ²- and Ξ³-
87:
There is a great diversity in biological traits. Denitrifying bacteria have been identified in over 50 genera with over 125 different species and are estimated to represent 10-15% of bacteria population in water,
879:
Anenberg, Susan C.; Schwartz, Joel; Shindell, Drew; Amann, Markus; Faluvegi, Greg; Klimont, Zbigniew; Janssens-Maenhout, Greet; Pozzoli, Luca; Van
Dingenen, Rita; Vignati, Elisabetta; Emberson, Lisa (June 2012).
417:. Another important environmental issue concerning denitrification is the fact that the process tends to produce large amounts of by-products. Examples of by-products are nitric oxide (NO) and nitrous oxide (N
989:
Powell, Shane M.; Ferguson, Susan H.; Snape, Ian; Siciliano, Steven D. (March 2006). "Fertilization
Stimulates Anaerobic Fuel Degradation of Antarctic Soils by Denitrifying Microorganisms".
1089:
Wu, M. L.; van
Teeseling, M. C. F.; Willems, M. J. R.; van Donselaar, E. G.; Klingl, A.; Rachel, R.; Geerts, W. J. C.; Jetten, M. S. M.; Strous, M.; van Niftrik, L. (2011-10-21).
600:
Ji, Bin; Yang, Kai; Zhu, Lei; Jiang, Yu; Wang, Hongyu; Zhou, Jun; Zhang, Huining (August 2015). "Aerobic denitrification: A review of important advances of the last 30 years".
136:
as environments that are highly saline and high in temperature. Aerobic denitrifiers can conduct an aerobic respiratory process in which nitrate is converted gradually to N
371:. However, methane oxidation also takes place in anoxic, or oxygen depleted zones, of freshwater bodies. In the case of Lake Constance, this is carried out by
351:, water, and energy) in deep freshwater bodies of water. This is important because methane is the second most significant anthropogenic greenhouse gas, with a
1205:
Park, Hee-Deung; Noguera, Daniel R (August 2004). "Evaluating the effect of dissolved oxygen on ammonia-oxidizing bacterial communities in activated sludge".
52:
using various enzymes, including nitrate reductase (NAR), nitrite reductase (NIR), nitric oxide reductase (NOR) and nitrous oxide reductase (NOS), turning
196:
different half reactions each requiring a specific enzyme. The transformation from nitrate to nitrite is performed by nitrate reductase (Nar)
1266:
445:
Denitrifying bacteria are an essential component in treating wastewater. Wastewater often contains large amounts of nitrogen (in the form of
882:"Global Air Quality and Health Co-benefits of Mitigating Near-Term Climate Change through Methane and Black Carbon Emission Controls"
175:
The most common denitrification process is outlined below, with the nitrogen oxides being converted back to gaseous nitrogen:
1091:"Ultrastructure of the Denitrifying Methanotroph "Candidatus Methylomirabilis oxyfera," a Novel Polygon-Shaped Bacterium"
268:
It is important to note that any of the products produced at any step can be exchanged with the soil environment.
307:
changes. The extent to which anthropogenic methane affects the atmosphere is known to be a significant driver of
352:
1292:
1146:
Huang, Ting-Lin; Zhou, Shi-Lei; Zhang, Hai-Han; Zhou, Na; Guo, Lin; Di, Shi-Yu; Zhou, Zi-Zhen (2015-04-10).
316:
169:
1297:
1042:"The indirect global warming potential and global temperature change potential due to methane oxidation"
801:
1302:
1214:
1053:
998:
953:
816:
745:
669:
540:
304:
734:"Anaerobic methane oxidation coupled to denitrification is the dominant methane sink in a deep lake"
355:
25 times more potent than that of carbon dioxide, and freshwaters are a major contributor of global
482:
410:
132:
248:
Nitrous oxide reductase (Nos) terminates the reaction by converting nitrous oxide into dinitrogen
26:
that encompass many different phyla. This group of bacteria, together with denitrifying fungi and
1307:
858:
625:
566:
281:
299:
The process of anaerobic denitrification may contribute significantly to the global methane and
1287:
1262:
1230:
1187:
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49:
39:
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832:
824:
771:
753:
685:
677:
609:
548:
292:
131:
The majority of denitrifying bacteria are facultative aerobic heterotrophs that switch from
331:
well as the lacking any toxic or undesirable leftovers, as are left by other metabolisms.
31:
1148:"Nitrogen Removal from Micro-Polluted Reservoir Water by Indigenous Aerobic Denitrifiers"
1218:
1057:
1040:
Boucher, Olivier; Friedlingstein, Pierre; Collins, Bill; Shine, Keith P (October 2009).
1002:
957:
820:
749:
673:
544:
1182:
1147:
1123:
1090:
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1041:
914:
881:
776:
733:
487:
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323:
312:
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300:
53:
35:
1281:
732:
Deutzmann, Joerg S.; Stief, Peter; Brandes, Josephin; Schink, Bernhard (2014-12-03).
681:
553:
528:
414:
322:
Additionally, microorganisms which employ this type of metabolism may be employed in
68:
629:
570:
120:
862:
368:
1226:
1258:
470:
400:
Denitrification effects on limiting plant productivity and producing by-products
327:
107:
101:
802:"A microbial consortium couples anaerobic methane oxidation to denitrification"
966:
941:
613:
43:
1173:
1114:
1075:
1018:
975:
942:"Hypoxia-induced shifts in nitrogen and phosphorus cycling in Chesapeake Bay"
905:
846:
767:
699:
621:
758:
340:
1234:
1191:
1132:
1026:
923:
854:
785:
707:
383:, which is a species of bacteria that acts as a denitrifying methanotroph.
232:
Nitric oxide reductase (Nor) then converts nitric oxide into nitrous oxide
562:
1164:
446:
113:
93:
46:
23:
1106:
897:
828:
339:
Denitrifying bacteria have been found to play a significant role in the
450:
285:
27:
1010:
837:
690:
291:
was first observed in 2008, with the isolation of a methane-oxidizing
422:
288:
119:
16:
Bacteria using nitrate and nitrite as a terminal electron acceptor
216:
Nitrite reductase (Nir) then converts nitrite into nitric oxide
89:
57:
517:
Microbiology and
Molecular Biology Reviews, 61(4), 533β616
303:, especially in light of the recent influx of both due to
277:
Anaerobic oxidation of methane coupled to denitrification
311:, and considering it is multiple times more potent than
529:"The chemical mechanism of microbioal denitrification"
168:
Denitrifying bacteria use denitrification to generate
515:
Cell biology and molecular basis of denitrification.
99:
Denitrifying include for example several species of
645:Bothe, H., Ferguson, S., & Newton, W. (2007).
940:Testa, Jeremy Mark; Kemp, W. Michael (May 2012).
441:Denitrifying bacteria use in wastewater treatment
1253:, Royal Society of Chemistry, pp. 368β418,
738:Proceedings of the National Academy of Sciences
335:Role of denitrifying bacteria as a methane sink
8:
588:Soil microbiology, ecology, and biochemistry
1152:International Journal of Molecular Sciences
590:(4th ed.). Chapter 14 Amsterdam: Elsevier.
527:Averill, B.A.; Tiedje, J.M. (1982-02-08).
1181:
1163:
1122:
1065:
965:
913:
836:
775:
757:
689:
552:
461:) and nitrite oxidizing bacteria (NOB, NO
395:Denitrifying bacteria and the environment
602:Biotechnology and Bioprocess Engineering
272:Oxidation of methane and denitrification
74:
63:
641:
639:
582:
580:
509:
507:
505:
503:
499:
379:-like bacteria are bacteria similar to
991:Environmental Science & Technology
935:
933:
7:
874:
872:
727:
725:
723:
721:
719:
717:
381:Candidatus Methylomirabilis oxyfera
347:) (where methane is converted to CO
127:a species of denitrifying bacteria
83:Diversity of denitrifying bacteria
14:
886:Environmental Health Perspectives
682:10.1111/j.1462-2920.2008.01724.x
1046:Environmental Research Letters
647:Biology of the nitrogen cycle.
362:A study conducted on Europe's
326:, as shown by a 2006 study of
1:
1227:10.1016/j.watres.2004.04.047
1067:10.1088/1748-9326/4/4/044007
554:10.1016/0014-5793(82)80383-9
1259:10.1039/9781782623762-00368
284:denitrification coupled to
30:, is capable of performing
1324:
946:Limnology and Oceanography
662:Environmental Microbiology
967:10.4319/lo.2012.57.3.0835
614:10.1007/s12257-015-0009-0
164:Denitrification mechanism
433:which can contribute to
353:global warming potential
224:+ 4 H + 2 e β 2 NO + 2 H
1095:Journal of Bacteriology
759:10.1073/pnas.1411617111
425:depleting species and N
369:methanotrophic bacteria
22:are a diverse group of
128:
513:Zumft, W. G. (1997).
125:Pseudomonas stutzeri,
123:
20:Denitrifying bacteria
1213:(14β15): 3275β3286.
1165:10.3390/ijms16048008
649:Amsterdam: Elsevier.
236:2 NO + 2 H + 2 e β N
1219:2004WatRe..38.3275P
1107:10.1128/jb.05816-11
1058:2009ERL.....4d4007B
1003:2006EnST...40.2011P
958:2012LimOc..57..835T
898:10.1289/ehp.1104301
829:10.1038/nature04617
821:2006Natur.440..918R
750:2014PNAS..11118273D
744:(51): 18273β18278.
674:2008EnvMi..10.3164E
545:1982FEBSL.138....8A
483:Nitrifying bacteria
411:nitrifying bacteria
133:aerobic respiration
586:Eldor, A. (2015).
129:
1268:978-1-78262-334-2
1011:10.1021/es051818t
815:(7086): 918β921.
668:(11): 3164β3173.
357:methane emissions
256:O + 2 H + 2 e β N
183:+ 10 e + 12 H β N
56:back to nitrogen
40:electron acceptor
1315:
1272:
1271:
1245:
1239:
1238:
1202:
1196:
1195:
1185:
1167:
1158:(4): 8008β8026.
1143:
1137:
1136:
1126:
1086:
1080:
1079:
1069:
1037:
1031:
1030:
997:(6): 2011β2017.
986:
980:
979:
969:
937:
928:
927:
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876:
867:
866:
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656:
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597:
591:
584:
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524:
518:
511:
375:-like bacteria.
293:bacterial strain
204:+ 2 H + 2 e β NO
78:
66:
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54:nitrogen oxides
34:as part of the
32:denitrification
17:
12:
11:
5:
1321:
1319:
1311:
1310:
1305:
1300:
1295:
1293:Nitrogen cycle
1290:
1280:
1279:
1274:
1273:
1267:
1251:Metallobiology
1240:
1207:Water Research
1197:
1138:
1101:(2): 284β291.
1081:
1032:
981:
952:(3): 835β850.
929:
892:(6): 831β839.
868:
791:
713:
651:
635:
608:(4): 643β651.
592:
576:
519:
498:
497:
495:
492:
491:
490:
488:Nitrogen Cycle
485:
478:
475:
466:
462:
458:
454:
442:
439:
435:global warming
431:greenhouse gas
429:O is a potent
426:
418:
409:by species of
401:
398:
396:
393:
364:Lake Constance
348:
344:
343:of methane (CH
336:
333:
324:bioremediation
313:carbon dioxide
309:climate change
278:
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158:Proteobacteria
153:
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84:
81:
36:nitrogen cycle
15:
13:
10:
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3:
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1077:
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1063:
1059:
1055:
1052:(4): 044007.
1051:
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1043:
1036:
1033:
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1024:
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1016:
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1004:
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476:
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472:
471:heterotrophic
452:
448:
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432:
424:
421:O). NO is an
416:
415:cyanobacteria
412:
408:
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394:
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365:
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305:anthropogenic
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69:nitrous oxide
59:
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37:
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25:
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1298:Soil biology
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533:FEBS Letters
532:
522:
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321:
319:conditions.
298:
280:
267:
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231:
215:
194:
174:
167:
157:
130:
124:
117:and others.
112:
106:
100:
98:
86:
19:
18:
1303:Fishkeeping
539:(1): 8β12.
328:hydrocarbon
108:Alcaligenes
102:Pseudomonas
47:nitrogenous
1282:Categories
838:1874/22552
691:2066/72144
494:References
389:M. oxyfera
377:M. oxyfera
373:M. oxyfera
44:metabolize
1308:Aquariums
1174:1422-0067
1115:0021-9193
1076:1748-9326
1019:0013-936X
976:0024-3590
906:0091-6765
847:0028-0836
768:0027-8424
700:1462-2912
622:1226-8372
341:oxidation
289:oxidation
282:Anaerobic
50:compounds
1288:Bacteria
1235:15276744
1192:25867475
1133:22020652
1027:16570629
924:22418651
855:16612380
786:25472842
708:18721142
630:85744076
571:84456021
477:See also
447:ammonium
413:and the
148:β NO β N
114:Bacillus
94:sediment
24:bacteria
1215:Bibcode
1183:4425064
1124:3256638
1054:Bibcode
999:Bibcode
954:Bibcode
915:3385429
863:4413069
817:Bibcode
777:4280587
746:Bibcode
670:Bibcode
563:7067831
541:Bibcode
451:nitrate
407:fixated
317:hypoxic
286:methane
42:. They
28:archaea
1265:
1233:
1190:
1180:
1172:
1131:
1121:
1113:
1074:
1025:
1017:
974:
922:
912:
904:
861:
853:
845:
809:Nature
784:
774:
766:
706:
698:
628:
620:
569:
561:
859:S2CID
805:(PDF)
626:S2CID
567:S2CID
423:ozone
240:O + H
187:+ 6 H
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