As E. coli K-12 is used for many kinds of biological experimentation (mainly recombinant DNAexperiments), it is important to know the optimal conditions for growth and the bacteria’s tolerancesto certain environmental factors and introduced substances. In order to control as many variables aspossible when conducting recombinant DNA experiments, it is ideal to culture E. coli in its optimalgrowth conditions so as to not induce stress, causing mutation and reproduction of that mutation.