(93t) Inhibition of Bioluminescent Gene Expression in Whole-Cell Bacterial Biosensors Using a High Temperature Switch

Whole-cell biosensors utilize the natural processes of living cells to detect changes in their environment. The Pseudomonas putida strain TVA8 bacterial-based biosensor is used to sense parts-per-billion levels of chemicals or inducers (i.e. trichloroethylene) through bioluminescence. However, the technical challenge in detecting changes in inducer concentrations is to engineer a quantitative link between the bioluminescence signal and the inducer concentration. One way to calibrate the biosensor is to ?reset? or ?turn off? the bioluminescence signal. The goal of this study is to determine a method for ?turning off? the bioluminescence in P. putida strain TVA8, through controlled heating to denature proteins involved in the bioluminescence mechanism. The bacteria were grown at 27 °C on TCE-saturated minimal media shaking at 220 RPM. At 8 hours, the temperature was increased to 37 °C using a water bath. The bioluminescence was recorded once per hour prior to the temperature change and once per minute after the change. The bioluminescence signal was found to decrease rapidly, with an average of 95.388 ± 1.59% of the maximum bioluminescence eliminated after 2 minutes. Therefore, it is possible to eliminate the bioluminescence signal using a high temperature (37 °C) control ?switch?, which is necessary for sensor calibration.