Boltzmann statistics as founding principle of microbial growth

Elie Desmond-Le Quéméner (1) , Théodore Bouchez (1)

1 BIOMIC

Microbes are the most abundant living forms on earth and major contributors to the biogeochemical cycles. However, our ability to model their dynamics only relies on empirical laws, fundamentally restricting our understanding and predictive capacity in many environmental systems. Preeminent physicists such as Schrödinger and Prigogine have introduced a thermodynamic interpretation of life, paving the way for a quantitative theory. From these seminal contributions have emerged microbial thermodynamics, which allows the prediction of microbial energy allocation. Nevertheless, the link between energy balances and growth dynamics is still not understood. Here we demonstrate a microbial growth equation relying on an explicit theoretical ground sustained by Boltzmann statistics. Historical data from Monod are used to illustrate the experimental accuracy of our law. In addition, two classes of microbial isotopic fractionation behavior are predicted and we show how their existence is supported by recent experimental reports. Our work opens the door to the modeling of microbial population dynamics through a thermodynamic state analysis of environmental systems. We anticipate that the predictive power of our law could be used to design and control biotechnological processes and applications. The contribution of microbial reactions to earth biogeochemical cycles could also be more accurately modeled. Importantly, our theory offers a new framework to mathematically assess ecological and evolutionary concepts.

Mots clés: microbial division; growth rate; exergy; Gibbs energy; statistical physics; flux force relationship

Domaines: Ecologie, Environnement

Elie Desmond-Le Quéméner, Théodore Bouchez. Boltzmann statistics as founding principle of microbial growth. 2013. ⟨hal-00825781v1⟩