Emergence of diauxie as an optimal growth strategy under resource allocation constraints in cellular metabolism
Pierre Salvy, Vassily Hatzimanikatis
Abstract
Significance When several sugars are at its disposition, the bacterium Escherichia coli consumes them in a specific order—a behavior called diauxie. We developed a framework combining dynamic methods and models of metabolism and gene expression to show that diauxie and its associated lag in cell growth can be explained simply as an optimal behavior under constraints on the protein amount and renewal in a cell. We validate our model by reproducing experimental results and successfully predict a diauxic behavior on a growth medium containing two types of sugar, glucose and lactose. Finally, we claim that the regulation mechanism inducing diauxie (the lac operon) is a control system to implement growth optimality at the cellular level.