Statistical Thermodynamics of Cellular Metabolism and Growth*

Cell metabolism is modeled using a maximum entropy production rate assumption from which rate parameters can be inferred for use in simulating the mass action kinetics of metabolism. Simulation predictions of metabolite levels of central metabolism of Neurospora crassa and Yarrowia lipolytica then allow for inference of enzyme regulation for both fungi. Subsequent simulations with regulation provide predictions of metabolite levels that are comparable to experimental measurements and can be used to create free energy maps of metabolic pathways. Simulations elucidate the dissipative role of the Crabtree/Warburg effect of overflow metabolism, and provide a more complete understanding of biological cells as adaptive, dissipative structures. Statistical thermodynamics is also combined with data analysis to measure the work required to create a cell (in kJ/gm cells or kJ/mol cells) and the power (in Watts) generated by cells during growth. It is estimated that a bacterial cell produces has approximately the same power/weight ratio as the most efficient fuel cells.