Modeling substrate inhibition of microbial growth

Area of Science:

• Microbiology
• Biophysics
• Chemical Kinetics

Background:

• Substrate inhibition is a common phenomenon in microbial growth, impacting productivity.
• Existing empirical models, like the Haldane-Andrews equation, lack a strong physical basis for microbial systems.
• There is a need for a physically grounded model to describe substrate inhibition in microbial growth.

Purpose of the Study:

• To present a general, statistically thermodynamic equation for microbial growth with substrate inhibition.
• To demonstrate that existing empirical models can be derived from this general equation.
• To validate the general equation's ability to model experimental data and determine inhibition sites.

Main Methods:

• Developed a general equation for substrate inhibition using statistical thermodynamics.
• Derived established empirical models (e.g., Haldane-Andrews) from the general equation.
• Tested the general equation against three literature datasets of microbial growth.
• Adapted and developed a graphical method for determining inhibition sites.

Main Results:

• The general equation accurately represents all three tested experimental datasets.
• The general equation provides a physically meaningful interpretation of empirical parameters.
• The adapted graphical method successfully determined the number of inhibition sites.
• The general equation outperformed a widely used empirical model in data fitting.

Conclusions:

• The statistical thermodynamic approach provides a robust, physically based framework for microbial substrate inhibition.
• The general equation offers superior modeling capabilities compared to existing empirical models.
• The developed method allows for the quantitative determination of inhibition sites in bacterial cells.