Construction of a sensitive and specific lead biosensor using a genetically engineered bacterial system with a luciferase gene reporter controlled bypbrandcadApromoters

Abstract

Background A bacterial biosensor refers to genetically engineered bacteria that produce an assessable signal in the presence of a physical or chemical agent in the environment. Methods We have designed and evaluated a bacterial biosensor expressing a luciferase reporter gene controlled bypbrandcadApromoters inCupriavidus metallidurans(previously termedRalstonia metallidurans) containing theCH34andpI258plasmids ofStaphylococcus aureus, respectively, and that can be used for the detection of heavy metals. In the present study, we have produced and evaluated biosensor plasmids designatedpGL3-luc/pbrbiosensor andpGL3-luc/cadbiosensor, that were based on the expression of luc+ and under the control of thecadpromoter and thecadCgene ofS. aureusplasmidpI258andpbrpromoter andpbrRgene from plasmidpMOL30ofCupriavidus metallidurans. Results We found that thepGL3-luc/pbrbiosensor may be used to measure lead concentrations between 1-100 mu M in the presence of other metals, including zinc, cadmium, tin and nickel. The latter metals did not result in any significant signal. ThepGL3-luc/cadbiosensor could detect lead concentrations between 10 nM to 10 mu M. Conclusions This biosensor was found to be specific for measuring lead ions in both environmental and biological samples.