Environmental contamination by heavy metals is a worldwide problem. Therefore, it is necessary to
develop sensitive, effective and inexpensive methods, which can efficiently monitor and determine the level of hazardous
metals in the environment. Conventional techniques to analyze metals, suffer from the disadvantages of high cost.
Alternatively, development of simple system for monitoring heavy metals pollution is therefore needed. The present
approach is based on the use of bacteria that are genetically engineered so that a measurable signal is produced when the
bacteria are in contact with the bioavailable metal ions. Reporter genes are widely used as genetic tools for quantification
and detection of specific cell population, gene expression and constructing whole cell biosensors as specific and
sensitive devices for measuring biologically relevant concentrations of pollutants. An attempt has been made to
construct the reporter gene enhanced green fluorescent protein and was expressed under the control of
cadR gene,
responsible for cadmium resistance. Recombinant strain
Escherichia coli
cadR30 was used, that carried
cadR gene in
pET30b expression vector and cloned. Clones confirmed by the expression of enhanced green fluorescent protein was
detected under ultraviolet illumination and separated on sodium dodecyl sulfate polyacrylamide gel electrophoresis.
The construction of green fluorescent protein based
Escherichia coli bacterial biosensor was developed based on green
fluorescent protein expression under the control
cadR gene of
Pseudomonas aeruginosa
BC15. The constructed
bacterial biosensor is useful and applicable in determining the availability of heavy metals in soil and wastewater.
