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Development of wholecell bioreporters for detection of boric acid, cyanide and paraquat

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2019
Suluova, Melek
Chemical industry is one of the fastest growing sectors in the world due to immensely increasing human population. In despite of precautions ruled by legislations, many chemicals are produced and released to into environment. These pollutants get into soil, water and air thus to our food, resulting in serious toxic effects on human health and the destruction of ecosystems. Boric acid, paraquat and cyanide are example for pollution causing chemicals. Due to their possible toxicity, continuous monitoring is needed on environmental samples. Whole cell biosensors are one of the promising devices to screen various compounds in environmental samples. They are analytical devices that convert a biological response into an electrical signal. These systems have a lot of advantageous properties in comparison with chemical methods. The aim of this study was to develop whole cell biosensor method by designing new bioreporter cell constructs against boric acid, cyanide and paraquat. E. coli K12 MG1655 was used as a model organism and green fluorescence protein gene (gfp) was used as a reporter gene. By this study, grpE gene promoter was used for the first time for the detection of boric acid. It was detected at 18th hour with 50 mM detection limit. hdeBAD operon promoter included in cyanide detection in this study was not used before in bioreporter studies at all. By using this promoter, cyanide was detected at 3rd hour with 100 µM detection limit. sodA gene promoter is widely used for paraquat detection studies. In this work, lower detection range was tested. Therefore, paraquat was detected at18th hour with 50 nM detection limit. At least 400% increase in fluorescence signal was observed in the experimental groups compared to the control group for detection of all three chemicals. Three different bioreporter cell groups developed in this study can be further developed and used in the production of fast, easy to use and on-site measurement systems.