A growth‐rate composition formula for the growth of E. coli on co‐utilized carbon substrates

Abstract

When bacteria are cultured in medium with multiple carbon substrates, they frequently consume these substrates simultaneously. Building on recent advances in the understanding of metabolic coordination exhibited by Escherichia coli cells through cAMP ‐Crp signaling, we show that this signaling system responds to the total carbon‐uptake flux when substrates are co‐utilized and derive a mathematical formula that accurately predicts the resulting growth rate, based only on the growth rates on individual substrates. image When cultured in medium containing two carbon substrates, E. coli frequently consumes both simultaneously. A mathematical formula based on simple assumptions accurately predicts the resulting growth rate from the growth rate on each substrate alone. Catabolite repression by cAMP‐Crp regulates the total carbon uptake flux through a negative feedback loop. The uptake of one substrate non‐specifically reduces the uptake of a second, co‐utilizable substrate. A growth‐rate composition formula is derived that accurately predicts the growth rate on two co‐utilized substrates based on the growth rate on either substrate alone.