Affinity informs environmental cooperation between ammonia-oxidizing archaea (AOA) and anaerobic ammonia-oxidizing (Anammox) bacteria
Anaerobic ammonia-oxidizing (Anammox) bacteria (AnAOB) rely on nitrite supplied by ammonia-oxidizing bacteria (AOB) and archaea (AOA). Affinities for ammonia and oxygen play a crucial role in AOA/AOB competition and their association with AnAOB. In this work we measured the affinity constants for am...
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Published in | The ISME Journal Vol. 13; no. 8; pp. 1997 - 2004 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
London
Nature Publishing Group UK
01.08.2019
Nature Publishing Group |
Subjects | |
Online Access | Get full text |
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Summary: | Anaerobic ammonia-oxidizing (Anammox) bacteria (AnAOB) rely on nitrite supplied by ammonia-oxidizing bacteria (AOB) and archaea (AOA). Affinities for ammonia and oxygen play a crucial role in AOA/AOB competition and their association with AnAOB. In this work we measured the affinity constants for ammonia and oxygen (half-saturation;
k
m
) of two freshwater AOA enrichments, an AOA soil isolate (
N. viennensis
), and a freshwater AnAOB enrichment. The AOA enrichments had similar kinetics (
μ
max
≈ 0.36 d
−1
,
k
m,NH4
≈ 0.78 µM, and
k
m,O2
≈ 2.9 µM), whereas
N. viennensis
had similar
k
m
values but lower
μ
max
(0.23 d
−1
). In agreement with the current paradigm, these AOA strains showed a higher affinity for ammonia (lower
k
m,NH4
; 0.34–1.27 µM) than published AOB measurements (>20 µM). The slower growing AnAOB (μ
max
≈ 0.16 d
−1
) had much higher k
m
values (
k
m,NH4
≈ 132 µM,
k
m,NO2
≈ 48 µM) and were inhibited by oxygen at low levels (half-oxygen inhibition;
k
i,O2
≈ 0.092 µM). The higher affinity of AOA for ammonia relative to AnAOB, suggests AOA/AnAOB cooperation is only possible where AOA do not outcompete AnAOB for ammonia. Using a biofilm model, we show that environments of ammonia/oxygen counter diffusion, such as stratified lakes, favors this cooperation. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1751-7362 1751-7370 |
DOI: | 10.1038/s41396-019-0408-x |