Figure 2. Reconstruction, analysis, and wet lab validation of carbon fixation pathways in G. metallireducens.

A) A map of the two carbon fixation pathways included in the iAF987 reconstruction and encoded by genes annotated in the updated genome annotation. The two pathways, the reductive citric acid (TCA), and the dicarboxylate–hydroxybutyrate cycles share four reactions in the citric acid cycle. CO₂ fixation (and resulting acetyl-coA generated) and ATP-driven steps are shown in green and red, respectively. B) A graph of phenotypic data that demonstrated the model-predicted growth condition of formate as an electron donor and carbon source with Fe(III) as an electron acceptor is a viable growth condition. Carbon fixation is occurring under these conditions and the specifics of this process can be further elucidated in subsequent “drill-down” studies.