A Unified Theory for Microbial Growth Controlled by Multiple Limiting Substances

Generally speaking, models dealing with multiple limiting substances have mainly been derived from three different categories of studies, namely, multiple toxicity, multiple nutrient limitation and inhibition of enzyme catalysis. As different basic mechanisms were assumed by these models, a simple and unique theory which handles all these types of multiple-substance limited growth does not appear to exist. This paper presents a unified theory, based on a probabilistic foundation, for microbial growth controlled by multiple limiting substances (including both nutrient and toxicant). Most of the existing kinetic models in the aforementioned three areas can be generated using one theory. The theory has a broad application in many aspects, e.g. wastewater treatment, eutrophication studies, risk assessment, etc.