An engineered GFP fluorescent bacterial biosensor for detecting and quantifying silver and copper ions
Presented here are two engineered bacterial biosensors for detecting and quantifying silver and copper ions. The biosensors contain a silver/copper resistance operon and a Green Fluorescent Protein gene that is strictly regulated through silver activated promoter regions normally found on a silver resistance gene (sil operon). The two biosensors efficiently detected silver and copper concentrations of 40 µM–300 µM and 20 µM–600 µM respectively. A strong correlation (R2 = 0.90 or above) between silver/copper and GFP signal makes it possible to quantify the ions using a linear regression. At room temperature incubation, the GFP signal of the biosensors in Ag+ saturated after 13 h. However, a detectable GFP signal was seen in 4 h.
KeywordsBiosensors Two-component systems Silver Copper Environmental monitoring
This work was partially supported by a NSERC Discovery Grant. J.R.H was a Mitacs Elevate Fellowship recipient. We are grateful to Dr. Alex O’Neill of University of Leeds for the generous gift of strain J53(pMG101). In addition, we are grateful to Dr. Marc Habash at the University of Guelph for discussions and suggestions pertaining to the development of the biosensor.
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