Geneticists are now exploring ways to put D. radiodurans to use in cleaning up toxic chemical wastes in radioactive environments. Waste-eating bacteria have been used successfully in toxic waste cleanup, but all known strains cannot survive in a radioactive environment. Researchers Michael Daly of the Uniformed Services University of the Health Sciences, Larry Wackett at the University of Minnesota, and Jim Fredrickson of Pacific Northwest National Laboratory have teamed to construct a recombinant strain of D. radiodurans that could survive a mixed waste environment and degrade the organic chemicals to a less toxic state. Organic chemicals used by the U.S. nuclear weapons industry from 1945 to 1986 were frequently mixed with highly radioactive isotopes and buried in underground waste tanks. Some older tanks have leaked their hazardous contents into surrounding soils, spurring efforts to clean up the pollution at the source.
Bioremediation is one possible solution.
Daly and his colleagues are attempting to modify the D. radiodurans genome by adding genes from Pseudomonas , a strain of bacteria that can biodegrade trichloroethylene and toluene, two hazardous organic chemicals prevalent in mixed waste. The challenge these researchers face is to develop a strain of D. radiodurans that can not only resist radiation and the toxicity of metals and organic chemicals but also stay alive long enough to degrade all the chemical waste. Ever since food scientists discovered D. radiodurans in 1956 in a can of meat that had spoiled despite having been sterilized by radiation, researchers have attempted to discover why the bacterium evolved its resistance to radiation in the first place. Much scientific evidence now exists to support this hypothesis. This information will provide more clues to understanding this unusual organism and enhance its bioremediation capabilities.