Biosynthetic ability B, number R of metabolic reactions (size of metabolic networks), number RA of number of active reactions, and number N of carbon sources predicted to be catabolized in computational metabolic models of various organisms.

We took the number of synthesized molecules B, and the number of metabolic reactions R from the genome scale metabolic network reconstructions of these organisms, as listed in the column ‘References’. Active reactions are reactions that have non-zero flux as determined by FBA. We computed nutrient flexibilities by testing the viability of metabolic models on all known carbon containing metabolites that are educts or products of reactions in the global network by FBA, and assumed a metabolite to be a carbon source if the metabolic model can utilize it.