Application of Gibbs' Rule and a Simple Pathway Method to Microbial Stoichiometry

Abstract

Abstract The power of metabolic pathway stoichiometry for applications in bioreactor monitoring and control, in terms of the degrees of freedom, the calculation of reaction rates, and the validity of pathway models, is analyzed by using Gibbs' rule of stoichiometry. The pathway stoichiometry has significant advantages over the macroscopic balance methods when the number of independent reactions is not at its maximum. When the number of reactions is at the maximum, the power of the pathway stoichiometry is very much limited, and it should be used with caution. A simple method is also proposed to derive all possible independent stoichiometric constraints from the metabolic pathways. For most practical fermentations, the proposed method is much easier to use than the existing methods in the literature.