A recombinant protein is to be expressed under the control of the lac promoter and operator in a strain of E. coli having the genotype lacI<sup>+</sup> crp<sup>+</sup>. Even in the absence of inducer IPTG, low levels of expression of the recombinant protein are seen (leaky expression). Which one of the following should be done to minimize such leaky expression?

Correct Answer: Addition of excess glucose to the medium