Transitional Steady-State Investigations during Aerobic-Anaerobic Transition of Glucose Utilization by Escherichia coli K-12

Abstract

Transitional steady-state investigations during changes in oxygen tension under aerobic and during aerobic-anaerobic transition conditions were carried out with the aim of finding an indicator system which separates the equilibrium from the non-equilibrium state. Of the parameters used i.e. biomass formation, CO₂ production, Q_O2, NADH oxidase, succinate dehydrogenase, phosphofructokinase, glyceraldehyde-3-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and 2-oxoglutarate dehydrogenase, only the three enzymes requiring NADH or NADP for their function fulfilled the requirements. Biomass production and CO₂ formation were useful only during the aerobic-anaerobic transition period. In each case the reponse was immediate and the indicator systems demonstrated that a new steady state of oxygen was always obtained after 11 h which, at the specific growth rate used, was equivalent to at least two volume replacements of the growth vessel.