Figure 4.

Nitrogen uptake and intracellular storage. Circles represent experimental measurements (Zuñiga et al., 2016; A and B) and squares the predicted uptake rates (B and C). Every letter represents an experimental point in which all biomass compounds were collected. A, Experimental nitrogen concentration in the supernatant under photoautotrophy (green solid line) and heterotrophy (red solid line). Dashed lines represent the nitrate concentration over time (top x axis). B, Predicted uptake rate of NO₃ using the C. vulgaris genome-scale model iCZ843. Shaded areas show the experimental nitrate uptake rate under photoautotrophy (green) and heterotrophy (red). D, Predicted nitrogen consumption rates from the intracellular pool. The shaded areas are equivalent to the volumetric pool concentration and indicate nitrogen depletion from the culture medium. The first point of the definite integral was point b.