Figure 4.

Components of flux variability vs. ammonia uptake. Black circle represents Δ_int, red circle represents Δ_int + Δ_ext and green circle represents Δ_tot = Δ_int + Δ_ext + Δ_gro. (A) Aerobic conditions without coordination of carbon and nitrogen uptake. (B) Anaerobic conditions without coordination of carbon and nitrogen uptake. (C) Aerobic conditions with coordination of carbon and nitrogen uptake. (D) Anaerobic conditions with coordination of carbon and nitrogen uptake. The contribution of Δ_int and Δ_ext to flux variability, at low ammonia uptakes, disappears when the coordination of carbon and nitrogen utilization is imposed. Under coordination of carbon and nitrogen utilization, Δ_gro is the only significant component of flux variability.