Functional convergence in slow-growing microbial communities arises from thermodynamic constraints

Area of Science:

• Microbial Ecology
• Biophysics
• Systems Biology

Background:

• Microbial community dynamics are shaped by resource competition and byproduct exchange.
• Growth in anoxic environments is often slow due to thermodynamic equilibrium.
• Understanding community structure requires models that include energetic and thermodynamic constraints.

Purpose of the Study:

• To develop a microbial consumer-resource model incorporating energetic and thermodynamic constraints.
• To investigate how product inhibition affects microbial growth and community structure.
• To explain the observed convergence of microbial community function despite taxonomic variation.

Main Methods:

• Developed a microbial community consumer-resource model.
• Incorporated energetic and thermodynamic constraints into an interconnected metabolic network.
• Analyzed experimental data from anaerobic digesters.

Main Results:

• Product inhibition, alongside substrate depletion, constrains microbial growth.
• Community metabolic network structure and function converge, independent of species composition.
• The thermodynamic principle of maximum free energy dissipation governs community metabolic network structure.
• Functional convergence decreases in faster-growing communities.

Conclusions:

• Universal thermodynamic principles constrain microbial community metabolism.
• These principles explain functional convergence in microbial communities across diverse environments.
• The model provides insights into microbial community assembly and function in energy-limited ecosystems.