AN INTEGRATED METABOLIC MODELING APPROACH TO DESCRIBE THE ENERGY EFFICIENCY OF ESCHERICHIA-COLI FERMENTATIONS UNDER OXYGEN-LIMITED CONDITIONS - CELLULAR ENERGETICS, CARBON FLUX, AND ACETATE PRODUCTION

An integrated metabolic model for the production of acetate by growing Escherichia coli on glucose under serobic conditions is presented. The model is based on parameters which are easily determined by experiments. Forming the basis for this integrated metabolic model are the 12 principal precursor metabolites for biosynthetic pathways, the Embden-Meyerhof-Parnas pathway, the pentose phosphate cycle, the tricarboxylic acid cycle and the anapleurotic reactions, the Crabtree effect, the Pasteur effect, and the details of bacterial respiration. The result can be used to explain phenomena often observed in industrial fermentations, i.e., increased acetate production which follows from high glucose uptake rate, a low oxygen concentration, a high specific growth rate, or a combination of these conditions. (C) 1993 John Wiley & Sons, Inc.