Effect of global transcriptional regulators on kinetic behavior of Escherichia coli under anaerobic fermentation conditions

The phenotype of Escherichia coli is governed by global transcriptional regulators under variable environmental conditions. Fnr, ArcA, IhfA-B, Crp, and Fis are amongst the major global transcription regulators that change their activity across the range of aeration, hence forming the core transcriptional network responsible for survival under changing aeration conditions. Effect of deletion of these global transcription factors on the kinetics of cell growth and mixed acid production under anaerobic fermentation conditions has not been characterized. To quantify the kinetic parameters in the absence of global transcription factors, experiments were performed using single deletion mutants of the above-mentioned global transcription regulators. The absence of global transcription regulators resulted in a relatively higher glucose uptake rate than that required for the observed growth rate. This further resulted in a higher yield of mixed acids per unit biomass in mutants as compared to the parent strain (E. coli BW25113). Thus, the increased channeling of carbon towards mixed acid secretion resulted in a lower growth rate in the mutants.