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 determ ination of benzene in aqueous solution. A linear relationship between the sensor response and the concentration of benzene was observed up t o 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 2.8 2 muA/mM. Maximum error was estimated to be about 3.55 muM. The steady state response time was about 2-10 min within the linear range, compa rable to other biosensors currently in use. The sensor response was st able, reproducible and highly specific for the sensing of benzene. Wit h its specificity to benzene, rapid response and ease of operation, th is whole cell P. putida ML2 benzene biosensor has potential commercial application for the monitoring and sensing of benzene in industrial w aste effluent and in particular for monitoring benzene contamination i n groundwater.