The use of stoichiometric relations for the description and analysis of microbial cultures.

A general method is described, which enables the derivation of predictive fermentation equations for any microbiological process. The method combines the well-known achievements of the elemental balance approach with microscopic, metabolic balances and biochemical restrictions, using the key intermediates concept. Special attention is paid to the distinction between independent and dependent flow variables of a system. The method is fully illustrated for the very simple example of heterotrophic growth on a single substrate without product formation. Other examples include growth on mixed substrates and the description of catabolic and anabolic product formation.