Metabolic burden as a consequence of overexpression of target gene, in a recombinant strain of E. coli 1727 has been analyzed with respect to maintenance energy coefficient (m). The values of ’m’ for the host, uninduced recombinant and IPTG induced recombinant were determined to be 0.12, 0.17 and 0.32 g . g(-1). h(-1) respectively. Transient plasmid instability and nearly 33% fall in maximum specific growth rate were observed under conditions bf enhanced requirements for maintenance energy.