An amperometric benzene sensor using whole cell Pseudomonas putida ML2

Using a dissolved oxygen electrode and immobilized Pseudomonas putida ML2 whole cells, a biosensor was developed for the amperometric determination of benzene in aqueous solution. A linear relationship between the sensor response and the concentration of benzene was observed up to 1·35 mM in 50 mM phosphate buffer under the optimum conditions of pH 6·8 and at a temperature about 300K. Linear range sensitivity was 2·82 μA/mM. Maximum error was estimated to be about 3·55 μM. The steady state response time was about 2–10 min within the linear range, comparable to other biosensors currently in use. The sensors response was stable, reproducible and highly specific for the sensing of benzene. With its specificity to benzene, rapid response and ease of operation, this whole cell P. putida ML2 benzene biosensor has potential commercial application for the monitoring and sensing of benzene in industrial waste effluents and in particular for monitoring benzene contamination in groundwater.