Capacity of mercury volatilization by mer from Escherichia coli/ and glutathione S-transferase from Schistosoma mansoni/ genes cloned in Escherichia coli

A study was carried out to evaluate the capacity for mercury volatilization by genetically engineered strains that express the mer and glutathione S-transferase genes from Escherichia coli and Schistosoma mansoni, respectively. This method enabled strains containing simultaneously mer and glutathione S-transferase genes to grow in high concentra- tions of mercuric chloride 30 mgrml. and to volatilize part of the mercury 248 mgrg cell dry wt.. present in the culture medium, while strains bearing only a single gene, did not have the same behavior. Up to 70% of the total mercury of bacterial volatilization occurred in the first 4 h. Although the findings were preliminary, the genetically engineered strain containing simultaneously the mer and glutathione S-transferase genes show a great potential for bioremediation. It may be used in a closed system to remove by volatilization, and recover mercury Hg0. from contaminated effluents, such as industrial effluent, for instance.