Genetically Engineered p fabA p fabR Bacteria:  an Electrochemical Whole Cell Biosensor for Detection of Water Toxicity

We describe here a bacterial sensor for electrochemical detection of toxic chemicals. The sensor constitutes recombinant bacteria harboring plasmids encoding the fabA and fabR genes and has high-resolution amperometric response to membrane-damaging chemicals. For example, it can detect phenol at concentrations ranging between 1.6 and 16 ppm within 20 min. The high sensitivity is achieved by using the fabA promoter fused to a reporter gene-encoded β-galactosidase on a low copy number plasmid, under the control of the FabR repressor. The use of electrochemical whole cell sensors enables sensitive, fast, easy to operate, and cost-effective detection of water toxicity threats.