A GFP-based bacterial biosensor with chromosomally integrated sensing cassette for quantitative detection of Hg(Ⅱ) in environment

摘要

A mercury biosensor was constructed by integrating biosensor genetic elements into E. coli JM109 chromosome in a single copy number, using the attP/attB recombination mechanism of λ phage. The genetic elements used include a regulatory protein gene (merR) along with operator/promoter (O/P) derived from the mercury resistance operon from pDU1358 plasmid of Serratia marcescens. The expression of reporter gene gfp is also controlled by merR/O/P. Integration of the construct into the chromosome was done to increase the stability and precision of the biosensor. This biosensor could detect Hg(Ⅱ) ions in the concentration range of 100–1700 nmol/L, and manifest the result as the expression of GFP. The GFP expression was significantly different (P 0.05) for each concentration of inducing Hg(Ⅱ) ions in the detection range, which reduces the chances of misinterpretation of results. A model using regression method was also derived for the quantification of the concentration of Hg(Ⅱ) in water samples.