{'fraction_non_alphanumeric': 0.021081576535288724, 'fraction_numerical': 0.010999083409715857, 'mean_word_length': 5.033149171270718, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Growth and composition of Escherichia coli subjected to square‐wave perturbations in nutrient supply: Effect of varying amplitudes

The effect of regular variations in the input limiting nutrient concentration at different cycle amplitudes on the growth and composition (elemental and macromolecular) of Escherichia coli ML30 in chemostat culture is described. The cycle time was maintained constant at 2.0 hr. The basal level of nutrient fed to cultures was also maintained constant but the concentration amplitude was varied over a range from 0.2 to 5.0 g/liter. A lag between the stimulus and organisms response was observed and found to be independent of cycle amplitude over most of the range examined. Increasing the cycle amplitude did not effect the cell yield from glucose or the elemental composition of the organisms. However, large variations in the macromolecular composition of the cells (on a dry weight basis) were found; at 4.0 g/liter amplitude the cells contained some 82% protein. The relevance of this type of reactor operation in large‐scale fermentations is discussed.