SCIENCE AT THE EDGE SEMINAR SERIES

Interdisciplinary Physics Seminar

Friday, 16 March 2012 at 11:30am

Room 1400 Biomedical and Physical Sciences Bldg.

Refreshments at 11:15

Speaker: Doraiswami Ramkrishna
         H. C. Peffer Distiguished Professor
         School of Chemical Engineering
         Purdue University

Title:   Dynamic Modeling of Metabolism: The Cybernetic Approach

Abstract:

Metabolic networks feature a multitude of chemical reactions involving
uptake of external nutrients and transforming them to various intracellular
metabolites, fermentation products which are released into the surrounding
medium, and biomass. These reactions are catalyzed by highly specific enzymes
whose levels and activities are subject to control within a metabolic regulatory
system dictated by the genomic background of the organism. Dynamic modeling of
metabolic systems is essential to develop quantitative understanding of
biological systems and to facilitate design, optimization and control of
biotechnological processes. 

This presentation will discuss dynamic modeling of metabolic systems from
our cybernetic approach and compared with other modeling perspectives.  The
cybernetic approach is based on viewing regulatory processes as being inspired
by survival of one form or another. It postulates optimal investment of the
organism's resources for selective synthesis of enzymes that will drive
reactions favoring the organism's survival. The theory features the usual
concentration variables associated with reaction kinetics as well as cybernetic
variables that are control variables shown to depend only on reaction kinetics
from optimal control theory. These control variables concern both enzyme
syntheses and enzyme activities.        

Successful applications of cybernetic models to metabolism of bacteria and
yeast are presented. The cybernetic models represent the most promising tool
for metabolic engineering as they have a means to account for metabolic burden
imposed by pathway changes.