Fig. 1

Metabolic pathway of a CO₂-fixing E. coli. The central carbon metabolic pathway is shaded in dark gray, while the introduced CO₂-fixation bypass pathway composed of PRK and Rubisco is shaded in light gray. The metabolic flux index of heterotrophic CO₂-fixation, MFI_h-CO2, can be calculated by the equation at the bottom right, using the determined amount of unlabeled 3PGA (x mol) and ¹³C-labbled 3PGA (y mol). 3PGA, 3-phosphoglycerate; AcCoA acetyl-CoA, ACE acetate, DHAP dihydroxyacetone phosphate, E4P erythrose-4-phosphate, F6P frutose-6-phosphate, FBP fructose-1,6-biphosphate, G3P glyceraldehyde-3-phosphate, G6P glucose-6-phosphate, Glucon6P gluconate-6-phosphate, GlyOx glyoxylate, ICIT isocitrate, MAL malate, OAA oxaloacetate, PEP phosphoenolpyruvate, PRK phosphoribulokinase, PYR pyruvate, R5P ribose-5-phosphate, Ru5P ribulose-5-phosphate, Rubisco ribulose-1,5-bisphosphate carboxylase/oxygenase, RuBP ribulose 1,5-bisphosphate, S7P sedoheptulose-7-phosphate, SUC succinate, X5P xylulose-5-phosphate