Construction and Testing of EGFP Based Bacterial Biosensor for the Detection of Residual Tetracyclines in Milk and Wate

Abstract

A plasmid containing a transcriptional fusion between tetR regulated tet promoter from plasmid pOT182 and Enhanced Green Fluorescent Protein (EGFP) gene was created and was transformed into E. coli JM109 and this strain was used as whole cell bacterial biosensor for detection of tetracyclines in milk and water samples. The sensor strain E. coli JM109 (pJSKV41) was able to detect tetracycline in the range of 10-60 ng mL-1 sample and oxytetracycline in the range of 25-125 ng mL-1 of sample. When employed for detecting residual tetracyclines in pond water samples, the biosensor strain showed high sensitivity. Also the biosensor strain was able to detect residual tetracycline in goat milk even after 4 days of tetracycline treatment.