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Toxic compounds can have a negative effect on the performance of activated sludge systems in wastewater treatment systems. Monitoring the influent wastewaters by chemical analysis and periodic bioassays is too slow to avoid problems. The bioluminescent response of bacteria with the luciferase enzyme can provide quick and early toxicity information. Bacteria containing luciferase will bioluminesce under ideal conditions, but bioluminescence decreases as conditions deteriorate. The objective of this project was to evaluate the bioluminescent reporter in the bacterium Pseudomonas fluorescens to determine its suitability as an indicator of industrial toxicants. Bacteria containing the luciferase enzyme and a tetracycline-resistance gene were grown in a nutrient broth amended with 10 parts per million of tetracycline in batch cultures at 25 degrees Celsius. After 48 hours, the bacteria were tested for bioluminescence using a modified fluorometer. The bioluminescent cultures were standardized to 900 fluorescence standard units and used for dose-response bioassays. Toxins were added to the cultures in known concentrations and changes in bioluminescene were measured. Preliminary results found that a 0.02-percent sodium hypochlorite solution elicited an immediate decrease in bioluminescence. Solutions containing less than 1 milligram per liter chlorinated solvents, nickel (2+), and lead (2+), also elicited an immediate decrease in bioluminescence. However, other toxicants such as copper (2+), zinc (2+), and sodium thiosulfate enhanced bioluminescence at low concentrations (0.1 to 1.0 parts per million), but decreased initial bioluminescence by 50 percent at 100 parts per million. Petroleum compounds like toluene and benzene elicited an initial decrease in bioluminescence. However, incubating the bacteria with the toluene for 20 minutes increased the bioluminescence compared to control bacteria, possibly due to induction of toluene di-oxygenase. These preliminary results indicate bioluminescent bacteria might be useful as an early warning indicator of select toxicants.
This abstract can be cited as follows:
Sarfo, Robert , Byl, T.D., and Frymier, Paul , 2001, Evaluating a bioluminescent bacteria for measuring toxicity of industrial wastewaters [abs.], in Tennessee Water Resources Symposium, 11th, Burns, Tenn., 2001, Proceedings: Tennessee Section of the American Water Resources Association, p. P-12.
U.S. Department of the Interior, U.S. Geological Survey
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