The interaction between bioluminescence and heavy metal toxicity in synthetic water samples

The aim of this dissertation study is to use bioluminescent bacteria as an alternative to chemical-based, expensive and technological devices in order to determine the heavy metal ratio in municipal water systems. During the study, bioluminescent bacteria of four different genus which were obtained by the Department of Fundamental and Industrial Microbiology of Ege University Faculty of Science are used. Each bacterium is tested at different concentrations of heavy metals and their rate of bioluminescence were measured via a luminometer in an attempt to observe their interaction and to pick the strain that has the most sensitivity. As a conclusion of these tests, the most sensitive strain was determined as Photobacterium kishitanii. A growth rate graph is prepared using a spectrophotometer to observe the luminescence rate of the bioluminescent bacteria under normal conditions, following the selection of the most sensitive strain. The interaction between the organism and heavy metals was observed, right after determining the time period the organism grew and radiated the most, and allowed the organism to interact with heavy metals. Specifically 640 mM of Arsenic (arsenicum), 80 mM of Copper (cuprum) and 80 mM of Iron (ferrum) were used for preparing different concentrations and the maximum amount of existence of these elements in drinking waters is considered, in a specific attempt to contribute to public health. In conclusion, changes in the luminescence of the bioluminescent bacteria that has interacted in different concentrations of heavy metal environments were measured using a luminometer within a 3-day period. During these tests, rate of bioluminescence under normal conditions reached up to 300 RLU and no bioluminescence was observed at high concentrations. Considering public health, legal treshold of concentrations was observed as 200 RLU, 138 RLU and 100 RLU for arsenic, copper and iron, respectively.