ISME J

1751-7362

16

SCIE

[논문]Ammonia-oxidizing archaea possess a wide range of cellular ammonia affinities

Man-Young Jung, Christopher J. Sedlacek

정만영

K. Dimitri Kits

Anna J. Mueller

Sung-Keun Rhee

Linda Hink

Graeme W. Nicol

Barbara Bayer

Laura Lehtovirta-Morley

Chloe Wright

Jose R. de la Torre

Craig W. Herbold

Petra Pjevac

Holger Daims

Michael Wagner

Nitrification, the oxidation of ammonia to nitrate, is an essential process in the biogeochemical nitrogen cycle. The first step of
nitrification, ammonia oxidation, is performed by three, often co-occurring guilds of chemolithoautotrophs: ammonia-oxidizing
bacteria (AOB), archaea (AOA), and complete ammonia oxidizers (comammox). Substrate kinetics are considered to be a major
niche-differentiating factor between these guilds, but few AOA strains have been kinetically characterized. Here, the ammonia
oxidation kinetic properties of 12 AOA representing all major cultivated phylogenetic lineages were determined using
microrespirometry. Members of the genus Nitrosocosmicus have the lowest affinity for both ammonia and total ammonium of any
characterized AOA, and these values are similar to previously determined ammonia and total ammonium affinities of AOB. This
contrasts previous assumptions that all AOA possess much higher substrate affinities than their comammox or AOB counterparts.
The substrate affinity of ammonia oxidizers correlated with their cell surface area to volume ratios. In addition, kinetic
measurements across a range of pH values supports the hypothesis that—like for AOB—ammonia and not ammonium is the
substrate for the ammonia monooxygenase enzyme of AOA and comammox. Together, these data will facilitate predictions and
interpretation of ammonia oxidizer community structures and provide a robust basis for establishing testable hypotheses on
competition between AOB, AOA, and comammox.

2022-01-01

https://doi.org/10.1038/s41396-021-01064-z

https://doi.org/10.1101/2021.03.02.433310