Model of bacterial growth influenced by substrate C : N ratio and concentration

The present study describes and explores a model to determine bacterial gro wth, respiration and net ammonium remineralization as a function of the ave rage substrate C:N ratios and concentrations of organic substrates. Several experimental data sets were used to estimate critical parameters of the mo del. These data sets suggest that carbon and nitrogen growth efficiencies p lay a central role in the computation of bacterial growth, respiration, and net ammonium remineralization. The new parameterization of these processes , which takes into account the variability of carbon and nitrogen growth ef ficiencies with the C:N ratio of organic substrates, agrees with the observ ed experimental trends. The structure of the model and the results are comp ared to those of other models. According to the output of our model and to experimental data, which were used to validate parts of the structure, bact erial growth increases with organic substrate concentration and decreasing C:N ratios. As a consequence, a low carbon content relative to nitrogen in the substrates does not Limit bacterial growth.