Bioassay detection of some benzene derivatives using luminescent bacterium Vibrio sp. MM1 isolated from the Caspian Sea

Presence of different organic pollutions including benzene and its derivatives in water and wastewater has become a major concern. Cytotoxicity assay based on bacterial luminescence inhibition is useful method for detection of pollutants in the environment. Purpose of this study was the detection of some benzene derivatives using cytotoxicity assay based on luminescence inhibition of native Vibrio MM1 isolated from the Caspian Sea. In order to conduct the toxicity test, different concentration of some benzene derivatives was added individually to the growth culture of Vibrio MM1. The cytotoxicity of benzene derivatives was measured by considering the reduction of Vibrio MM1 luminescence using a luminometer. The results showed that the luminescent intensity of MM1 was significant reduced in the presence of benzene derivatives, so that a very low concentrations of benzene derivatives until 10-18 mgL-1 were measured. In addition, the EC50 value were measured 3.4×10-14 , 7.83×10 -13, 1.29×10 -8, 2.91×10 -9, 1.82 ×10 -5, 3.82× 10-8, 2.9×10-3 , 2×10-4, and 8.3 ×10-3 mgL-1 for benzene, ethylbenzene, bromobenzen, chlorobenzen, aniline, chlorophenol, nitrobenzene, resorcinol and pyrocatechol, respectively. To evaluate the acute and chronic effects of benzene derivatives, T1/2 parameter was calculated for each concentration. These results demonstrated that the concentration of 1.7×10-7 mgL-1 ethylbenzene and 1.9×10-8 mgL-1 nitrobenzene had the highest acute and chronic toxicity with the T1/2 values of 15.6 and 471.9 seconds, respectively. The results of current study indicated that the native luminescent Vibrio sp. MM1 can be useful for detection and cytotoxicity assessment of environmental pollutants including benzene derivatives.