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. (c) 2004 Elsevier Ltd. All rights reserved.