GROWTH RATE AND MOLAR GROWTH YIELD OF ESCHERICHIA COLI ADSORBED ON AN ANION-EXCHANGE RESIN

Abstract

Using a rapid continuous flow system (D=1), growth rates and molar growth yields of free and adsorbed cells of Escherichia coli were determined with glucose as a limiting substrate. In this system, free cells were continuously removed and a steady state in cell or substrate concentration in the liquid phase of culture was realized by the growth of adsorbed cells. Growth constants of free cells, μ and Y, were obtained from a washout curve of free cells and a corresponding curve of increase of a substrate. Growth constants of adsorbed cells, μ_a and Y_a, were obtained from steady state concentrations of cell and substrate in the liquid phase of culture during cultivation of adsorbed cells.
The growth rate of adsorbed cells depended both on substrate concentration and the amount of adsorbed cells. Saturation constants for growth, K_S, with glucose as a substrate were extremely high and they also depended on the amount of adsorbed cells. The maximal growth rate and the molar growth yield of adsorbed cells were much higher than those of free cells.