Simultaneous and gradual induction of beta-galactosidase and tryptophanase synthesis in an Escherichia coli batch culture.

beta-Galactosidase and tryptophanase can be induced in Escherichia coli simultaneously or gradually during a batch cultivation. In the strain Escherichia coli K 12 and ML 30, in which the synthesis of the two enzymes was induced simultaneously, only the synthesis of tryptophanase partially decreased, whereas the synthesis of beta-galactosidase was not influenced. In the strains B 28 and ATCC 9637 the synthesis of both enzymes was partially decreased. On a gradual induction of these enzymes in the strain Escherichia coli K 12 only the synthesis of tryptophanase decreased. Thus, the results obtained here resemble those observed during the simultaneous induction. In addition, it was found that it is not important which of the two enzymes is induced as the first one.