Thermodynamic Analysis of Glycolysis in Clostridium thermocellum and Thermoanaerobacterium saccharolyticum Using C and H Tracers.

and are thermophilic anaerobic bacteria with complementary metabolic capabilities that utilize distinct glycolytic pathways for the conversion of cellulosic sugars to biofuels. We integrated quantitative metabolomics with H and C metabolic flux analysis to investigate the reversibility and thermodynamics of the central metabolic networks of these two microbes. We found that the glycolytic pathway in operates remarkably close to thermodynamic equilibrium, with an overall drop in Gibbs free energy 5-fold lower than that of or anaerobically grown The limited thermodynamic driving force of glycolysis in could be attributed in large part to the small free energy of the phosphofructokinase reaction producing fructose bisphosphate.