Simultaneous mercury bioaccumulation and cell propagation by genetically engineered Escherichia coli

Genetically engineered Escherichia coli JM109, which expressed merT-merP protein and metallothionein (MT), was employed in this study to evaluate its potential for mercury bioaccumulation accompanied by simultaneous cell propagation in Hg2+ solution containing organic matters. In contrast to original host, E. coli JM109 which could hardly grow at 1 mg/L Hg2+ concentration, genetically engineered E. coli cells were able to propagate themselves in LB with Hg2+ concentration up to 7.4 mg/L, although cell reproduction was delayed with increasing Hg2+ concentration. Simultaneously, this strain could accumulate Hg2+ from LB + Hg2+ solutions effectively with more than 96% of mercury removal whether the cells were induced by IPTG or not. Cell propagation was somewhat inhibited by IPTG, but the capability of Hg2+-uptake of the induced cells was enhanced. These results suggested this strain could be used for the bioremediation of contaminated wastes containing mercury and organic matters.