Growth and composition of <i>Escherichia coli</i> subjected to square‐wave perturbations in nutrient supply: Effect of varying frequencies

Abstract

Abstract The effect of regularly varying the input nutrient concentration on the growth and composition (elemental and macromolecular) of Escherichia coli ML30 grown in chemostat culture is reported. After each change in substrate concentration a lag between the stimulus and organism response occurred, the magnitude of which was dependent upon the frequency of the perturbations. Both the growth yield and macromolecular composition of the cells were found to vary with the frequency of nutrient cycling: the yield decreased by some 10% as the cycle‐times decreased from 6.0 to 0.25 hr. It is suggested that maintaining microorganisms under controlled transient conditions might be useful in increasing yields of specific microbial products (e.g., single‐cell protein).