| Heavy metal pollution is a potential threat to human health,and Pb is an important source of heavy metal pollution.Traditional detection and analysis techniques,such as spectroscopic analysis and mass spectrometry,have the disadvantages of high cost,complicated sample preparation,and high personnel requirements.In some economically underdeveloped areas,it may be contaminated by lead from the mining industry or factories,but it lacks large analytical instruments and testing equipment,as well as senior technical personnel.Therefore,it is necessary to develop a rapid lead ion detection method that does not rely on large-scale analysis equipment.In this study,the ion-specific recognition operon pbr-pbrR was used as a recognition element,and the SRRz lysis gene derived from bacteriophage and endogenous?-galactosidase gene were used as reporter elements to construct a recombinant plasmid and introduce it into the host strain E.coli BL21.Thus,a biosensor for heavy metal lead detection is constructed.When the recombinant bacteria come into contact with the sample to be tested,the SRRz gene response causes the cells to lyse rapidly within 2 h,and the OD600 of the bacterial cultures or the?-galactosidase activity in supernatant can be tested to determine whether the sample contains heavy metal ions.The detection results can be displayed in two ways:one is the cell turbidity detected with a spectrophotometer or even the naked eye;the other is displayed through the Android application after the color reaction.The limits of detection are 1.44×10-7mol/L and 1.69×10-7 mol/L,which are lower than the 1.0 mg/L(4.8×10-6 mol/L)specified in the national sewage discharge standard.The water sample can be analyzed within 3 hours.Compared with the existing technology,this technology has good biological safety,no need to add reagents,no interference from pigments,low time consumption and low cost,and has lead ion specificity,which is easy to realize high-throughput screening and convenient for promotion. |
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