Question

What would happen when one grows a recombinant bacterium in the bioreactor but forget to add antibiotic to the medium in which the recombinant is growing?

Answer 1

In the absence of antibiotic there will be no pressure on recomb inants to retain the plasmid (containing the gene of our interest). Sinc e, maintaining a high copy number of plasmids is a metabolic burden to the microbial cells. It will thus tend to loose the plasmid.