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return to BIOREMEDIATION) |
| While some bacteria can
be used to biodegrade at waste sites, the microbes are killed by the
radiation before they are able to finish their task of degrading the
toxins. That is where Deinococcus radidurans comes into play.
Because D. radiodurans does not actually degrade the toxins, it will
be used in conjuction with microbes that can degrade.
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| Bioremediation with D.
radiodurans can be much cheaper and save a great amount of time.
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Bioremediation by Use of Genetic
Engineering |
| There have been several
studies where genes of pollutant degrading bacteria, such as
Pseudomonas have been added to this highly radiation resistant
bacteria. While D.radiodurans does not reduce radiation, it is
simply resistant to the radiation by repairing its DNA quickly.
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| Scientists transferred
a set of genes from pseudomonas into D. radiodurans that encode an
enzyme that partially breaks down toluene and other toxic chemicals.
This was accomplished by fusing a gene encoding toluene dioxygenase,
which is an enzyme that degrades toluene, to a Deinococcus
radiodurans promoter (a site that activates the gene. Then the DNA
was inserted into one of the bacterium's chromosomes, which
utimately resulted in a recombinant bacterium. The end result gives
you a bacterium that is capable of degrading toluene and other
organic compounds in a high-radiation environment. This genetically
engineered bacterium can withstand toluene and trichloroethylene at
levels that exceeds the levels found at many radioactive waste
sites. Even after the D. radiodurans has been exposed to radiation,
it is still able produce this valuable enzyme. This is important
because the "bug" is able to do its job in a highly radioactive
site. |
| Also, scientists have
successfully added genes to D. radiodurans that allow the microbe to
transform ionic mercury into a less toxic state. This is important
because mercury is a very common environmental contaminant.
Scientists, Daly and Brim haved proved that added mercury-altering
genes or any other new set of genes to D. radiodurans will not alter
its ability to withstand radiation. The microbe will still be able
to live in highly radioactive sites and be able to degrade many
toxins. |
| Next, scientists plan
to transfer a set of genes from pseudomonas into D. radiodurans that
will finish the breakdown of toxic waste. The genes will contain
proteins that will finish the break down of the toxins.
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| Eventually, with enough
research, hopefully D. radiodurans will be used to degrade many
organic chemicals and to immobilize radioactive metals. It may take
another six years before it is used out in the field. However, even
though Deinococcus radiodurans has not been known to cause death or
disease in humans, many humans are very skeptical of releasing
microbes into the soil.
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