Figure 4. Analysis of the citrate synthase (CS) reaction on Dehalococcoides growth.

(A) In the absence of the CS reaction, the TCA-cycle operates reductively via succinyl-CoA synthetase and 2-oxoglutarate synthase for producing biomass precursors for Dehalococcoides to grow. (B) The oxidative TCA-cycle operates when the CS reaction is present, but succinyl-CoA synthetase and 2-oxoglutarate synthase are absent, as suggested by the carbon labeling experiments [84]. However, Dehalococcoides growth remains almost unchanged with and without the CS reaction (0.0137 h⁻¹ vs. 0.014 h⁻¹) as represented by the flux values obtained from the growth simulations of iAI549.