A quantitative model of nitrogen fixation in the presence of ammonium

Keisuke Inomura; Jason Bragg; Lasse Riemann; Michael J. Follows

doi:10.1371/journal.pone.0208282

A quantitative model of nitrogen fixation in the presence of ammonium

Keisuke Inomura, Jason Bragg, Lasse Riemann, Michael J. Follows

Marine Biology

16 Citations (Scopus)

39 Downloads (Pure)

Abstract

Nitrogen fixation provides bioavailable nitrogen, supporting global ecosystems and influencing global cycles of other elements. It provides an additional source of nitrogen to organisms at a cost of lower growth efficiency, largely due to respiratory control of intra-cellular oxygen. Nitrogen-fixing bacteria can, however, utilize both dinitrogen gas and fixed nitrogen, decreasing energetic costs. Here we present an idealized metabolic model of the heterotrophic nitrogen fixer Azotobacter vinelandii which, constrained by laboratory data, provides quantitative predictions for conditions under which the organism uses either ammonium or nitrogen fixation, or both, as a function of the relative supply rates of carbohydrate, fixed nitrogen as well as the ambient oxygen concentration. The model reveals that the organism respires carbohydrate in excess of energetic requirements even when nitrogen fixation is inhibited and respiratory protection is not essential. The use of multiple nitrogen source expands the potential niche and range for nitrogen fixation. The model provides a quantitative framework which can be employed in ecosystem and biogeochemistry models.

Original language	English
Article number	e0208282
Journal	P L o S One
Volume	13
Issue number	11
Pages (from-to)	1-16
ISSN	1932-6203
DOIs	https://doi.org/10.1371/journal.pone.0208282
Publication status	Published - Nov 2018

Access to Document

10.1371/journal.pone.0208282

Inomura et al 2018, PlosOneFinal published version, 2.39 MBLicence: CC BY

Cite this

@article{6e57d5eb422b4dadad59d279d3f799a1,

title = "A quantitative model of nitrogen fixation in the presence of ammonium",

abstract = "Nitrogen fixation provides bioavailable nitrogen, supporting global ecosystems and influencing global cycles of other elements. It provides an additional source of nitrogen to organisms at a cost of lower growth efficiency, largely due to respiratory control of intra-cellular oxygen. Nitrogen-fixing bacteria can, however, utilize both dinitrogen gas and fixed nitrogen, decreasing energetic costs. Here we present an idealized metabolic model of the heterotrophic nitrogen fixer Azotobacter vinelandii which, constrained by laboratory data, provides quantitative predictions for conditions under which the organism uses either ammonium or nitrogen fixation, or both, as a function of the relative supply rates of carbohydrate, fixed nitrogen as well as the ambient oxygen concentration. The model reveals that the organism respires carbohydrate in excess of energetic requirements even when nitrogen fixation is inhibited and respiratory protection is not essential. The use of multiple nitrogen source expands the potential niche and range for nitrogen fixation. The model provides a quantitative framework which can be employed in ecosystem and biogeochemistry models.",

author = "Keisuke Inomura and Jason Bragg and Lasse Riemann and Follows, {Michael J.}",

year = "2018",

month = nov,

doi = "10.1371/journal.pone.0208282",

language = "English",

volume = "13",

pages = "1--16",

journal = "PLoS Computational Biology",

issn = "1932-6203",

publisher = "Public Library of Science",

number = "11",

}

TY - JOUR

T1 - A quantitative model of nitrogen fixation in the presence of ammonium

AU - Inomura, Keisuke

AU - Bragg, Jason

AU - Riemann, Lasse

AU - Follows, Michael J.

PY - 2018/11

Y1 - 2018/11

N2 - Nitrogen fixation provides bioavailable nitrogen, supporting global ecosystems and influencing global cycles of other elements. It provides an additional source of nitrogen to organisms at a cost of lower growth efficiency, largely due to respiratory control of intra-cellular oxygen. Nitrogen-fixing bacteria can, however, utilize both dinitrogen gas and fixed nitrogen, decreasing energetic costs. Here we present an idealized metabolic model of the heterotrophic nitrogen fixer Azotobacter vinelandii which, constrained by laboratory data, provides quantitative predictions for conditions under which the organism uses either ammonium or nitrogen fixation, or both, as a function of the relative supply rates of carbohydrate, fixed nitrogen as well as the ambient oxygen concentration. The model reveals that the organism respires carbohydrate in excess of energetic requirements even when nitrogen fixation is inhibited and respiratory protection is not essential. The use of multiple nitrogen source expands the potential niche and range for nitrogen fixation. The model provides a quantitative framework which can be employed in ecosystem and biogeochemistry models.

AB - Nitrogen fixation provides bioavailable nitrogen, supporting global ecosystems and influencing global cycles of other elements. It provides an additional source of nitrogen to organisms at a cost of lower growth efficiency, largely due to respiratory control of intra-cellular oxygen. Nitrogen-fixing bacteria can, however, utilize both dinitrogen gas and fixed nitrogen, decreasing energetic costs. Here we present an idealized metabolic model of the heterotrophic nitrogen fixer Azotobacter vinelandii which, constrained by laboratory data, provides quantitative predictions for conditions under which the organism uses either ammonium or nitrogen fixation, or both, as a function of the relative supply rates of carbohydrate, fixed nitrogen as well as the ambient oxygen concentration. The model reveals that the organism respires carbohydrate in excess of energetic requirements even when nitrogen fixation is inhibited and respiratory protection is not essential. The use of multiple nitrogen source expands the potential niche and range for nitrogen fixation. The model provides a quantitative framework which can be employed in ecosystem and biogeochemistry models.

U2 - 10.1371/journal.pone.0208282

DO - 10.1371/journal.pone.0208282

M3 - Journal article

C2 - 30496286

SN - 1932-6203

VL - 13

SP - 1

EP - 16

JO - PLoS Computational Biology

JF - PLoS Computational Biology

IS - 11

M1 - e0208282

ER -

A quantitative model of nitrogen fixation in the presence of ammonium

Abstract

Access to Document

Fingerprint

Cite this