(702a) Steady State Multiplicity of Chemical Reactors, an Early Topic of Varma’s Interest. What Does It Say for Bioreactors?

Steady states and their potential multiplicity are of crucial interest to continuous chemical and bioreactors. Any activity in this area must accord recognition to Arvind Varma, who as a prized product of the Minnesota legacy, began his early career on this subject. Yet, it would seem that the context of bioreactors does not present a scenario so grossly at variance from that of chemical reactors as to merit a special narration in a session honoring my good friend Arvind.

A strikingly distinct aspect of bioreactors, however, is the need to tangle with the complexity of large metabolic networks. Furthermore, the dynamic models required for this task must suitably recognize the role of metabolic regulation, a feature of the organism to navigate metabolism in specific ways as dictated by its gene network. The navigation is accomplished by preferred synthesis and activation of enzymes that catalyze specific reactions. While there is a substantial fraction of unknown regulatory features, even those that are known will add lavishly to the model complexity.

This talk will present a commentary on how cybernetic models, which treat regulation as a survival motivated goal of the organism, confront the problem of steady state multiplicity and stability of bioreactors to make predictions that have been experimentally confirmed.