Several luminescent bacteria were isolated from an Iranian shrimp farm located in Southeast part of Iran. Identification of isolated strains was performed by PCR amplification of 16srRNA, luxA and toxR genes. Data analysis showed three isolated strains have 99% similarity to Vibrio harveyi. As the application of luminescent bacteria in toxicity assessment of certain pesticides and herbicides have been well proved, in this study firstly, isolated strains were exposed to several toxicants in order to examine survival rate of the test organisms and their ability of light production at the presence of these chemicals. According to EC50 values of determined herbicides and pesticides, results revealed that among ten biocide tested in this research, Ethion, Amitraz and Phozalone had lower EC50. Also phenol had a significant impact on luminescent light emission of isolated strains. Luciferase is an essential enzyme for light production within luminescent bacteria and light emitting reaction of luminous bacteria biochemically related to this enzyme. Therefore in this study luciferase was extracted from three isolated luminescent bacteria by Q sepharose column chromatography. By using SDS PAGE method, the molecular weight of luciferase enzyme was determined which was about 80,000 daltons. The activity of luciferase was tested by adding its substrate. According to results the best light production was observed in 1mg/ml of FMN, 1mg/ml of NaBH4, 10µl/ml decanal and 0.01mg/ml of Pdcl2. The biosensory application of mentioned luciferase is under investigation

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