Researchers have developed a bacterial strain of
Deinococcus radiodurans that can detoxify both mercury
and toluene at nuclear waste sites.
provided by Nature Biotechnology
he trouble with most nuclear waste sites is that they
usually contain a nasty mess of heavy metals, organic chemicals,
and radioactive isotopes. Now, scientists have exploited the
hardy properties of the world's most radiation-resistant bacterium
to create a super bug that can tackle all these contaminants
at the same time. Unlike other pollution-eating bugs that quickly
die as a result of radioactivity exposure at atomic dumps, the
new bug is resistant to radiation and can be engineered with
the enzyme machinery to tackle both toxic metals and organics.
Michael
Daly and his colleagues had already shown that their hardy test
bacterium -- Deinococcus radiodurans can clean up the
fraction of organic waste present at radioactive sites. But many
atomic waste sites also contain other toxins, such as heavy metals,
as well as organic chemicals and radioactivity. What is needed
is a versatile bacterium that can not only tackle organic chemicals,
but also toxic metals, in a radioactive environment.
Daly's
team set about this task by creating four different strains of
D. radiodurans in which a set of foreign genes for converting
toxic mercury into its less harmful elemental form were placed
in the bacterium, either on circles of DNA (plasmids) or integrated
into the bacterial chromosome. All four strains were able to
grow in the presence of radiation and ionic mercury, and capable
of detoxifying mercury those strains containing many copies of
the genes being somewhat more efficient mercury vaporizers. The
team then went on to develop a strain that can detoxify both
mercury and toluene, a poisonous organic solvent, demonstrating
that different sets of gene can be slotted into D. radiodurans
to provide varied pollution-fighting attributes. Future efforts
are likely to attempt to integrate several other bioremediation
functions into the bacterium, creating a kind of superbug capable
of making a variety of types of waste less hazardous.
Author: Dr. Michael J. Daly, Dept. of Pathology Rm. B3153, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814-4799; (301) 295-3750; fax: (301) 295-1640; mdalyusuhs.mil.
he trouble with most nuclear waste sites is that they
usually contain a nasty mess of heavy metals, organic chemicals,
and radioactive isotopes. Now, scientists have exploited the
hardy properties of the world's most radiation-resistant bacterium
to create a super bug that can tackle all these contaminants
at the same time. Unlike other pollution-eating bugs that quickly
die as a result of radioactivity exposure at atomic dumps, the
new bug is resistant to radiation and can be engineered with
the enzyme machinery to tackle both toxic metals and organics.
Michael
Daly and his colleagues had already shown that their hardy test
bacterium -- Deinococcus radiodurans can clean up the
fraction of organic waste present at radioactive sites. But many
atomic waste sites also contain other toxins, such as heavy metals,
as well as organic chemicals and radioactivity. What is needed
is a versatile bacterium that can not only tackle organic chemicals,
but also toxic metals, in a radioactive environment.
usuhs.mil.