Nov 13, 2026
PLOS (Public Library of Science)
Author summary Microorganisms need two things to grow: energy and carbon. Catabolism supplies energy (e.g., ATP and NAD(P)H) and carbon (a set of precursor molecules) to anabolism. In microbiology, finding out how much ATP and how many (and which) precursors are required per unit biomass has been a central challenge for decades. We developed a method to decompose a metabolic network (e.g., a genome-scale stoichiometric model) into energy catabolism, precursor catabolism and anabolism. We aimed to make microbial biodiversity intelligible by comparing the bioenergetic and anabolic parameters across conditions and species. We found that the diversity is not reduced by disentangling metabolism into (energy and precursor) catabolism and anabolism. Rather, we found cases where almost all ATP was made in precursor synthesis and none in energy catabolism. Also, the precursor sets varied greatly in size and only a single precursor molecule was common across all studied cases. All of this is explained by the underlying biochemical details, which is the diversity we started with. Thus, our current concepts of catabolism and anabolism, and associated quantitative frameworks, do not reduce the complexity of microbial biodiversity and do not make it more intelligible in simple coarse-grained metabolic terms. The answers are in the biochemistry.