10.1371/journal.pone.0208282.g007 Keisuke Inomura Keisuke Inomura Jason Bragg Jason Bragg Lasse Riemann Lasse Riemann Michael J. Follows Michael J. Follows Respiration per protein as a function of C/N. Public Library of Science 2018 ambient oxygen concentration organism respires carbohydrate nitrogen fixation heterotrophic nitrogen fixer Azotobacter vinelandii ammonium Nitrogen fixation model 2018-11-29 19:01:56 Figure https://plos.figshare.com/articles/figure/Respiration_per_protein_as_a_function_of_C_N_/7402253 <p>Data (points) are shown as well as results of two simulation models. In one simulation (Sim1) energetically excess respiration can occur both during nitrogen fixation and during nitrogen limited growth on ammonium. In the second model (Sim2) excess respiration is allowed only during nitrogen fixation. Sim1 and Sim2 produce same amount of biomass. (i) 30% O<sub>2</sub> and (ii) 60% O<sub>2</sub>. Solids lines and points are same as <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0208282#pone.0208282.g003" target="_blank">Fig 3B</a>. The dilution rate is constant of 0.15 h<sup>-1</sup>, and red dashed lines show borders between different regimes (A: Carbohydrate limited, B: Ammonium limited, C: Nitrogen fixing as defined in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0208282#pone.0208282.g005" target="_blank">Fig 5</a>). Here 100% O<sub>2</sub> equals 225 μM thus approximately O<sub>2</sub> saturation under normal air composition at 30°C.</p>