What do a pile of crushed greenish rock soaked in sulfuric acid and the tsunami-caused damage to the Japanese Fukushima nuclear reactor have in common? Few people would guess that the link is bacteria, two in particular: Thiobacillus ferooxidans and Deinococcus radiodurans.
Bacterial Miners
For many years, the bacteria Thiobacillus ferooxidans has been used in copper mining operations to extract the metal from poor quality ore. This process replaces traditional methods using extreme heat or toxic chemicals and eliminates some of the environmental and health problems associated with the mining.
Thiobacillus ferooxidans oxidizes copper sulfide minerals that are washed out of the ore, making the process efficient even for mines of poor quality ore. A large fraction of all copper mined is produced through this method.
The Next Step
A natural next step in using bacteria in this way is to find or engineer bacteria that are able to interact with other heavy metals. This will yield more than a another way to recover minerals from low quality ore. Finding bacteria with the ability to extract heavy metals like mercury, cadmium, and arsenic could lead to new ways to clean up polluted industrial sites.
The site of the recent disaster at the Japanese nuclear power plants damaged by the earthquake and tsunami is precisely such a site. The radioactive material spread over the area near the plants could potentially contaminate the site for decades. Various cleaning methods will be used, and that might include the bacterial species, D. radiodurans, the only known bacteria able to survive high doses of radioactivity.
A Tough Problem Meets a Tough Answer
Deinococcus radiodurans was discovered in 1956 when scientists were trying to find new ways to preserve canned foods. It was a time when many researchers were looking for peaceful uses for nuclear power, and they knew a high dose of radiation could kill microorganisms. Examining a sample of treated meat that had spoiled, Arthur W. Anderson found D. radiodurans, the world's most resistant organism to radioactive exposure with the ability to withstand radiation doses several thousand times higher than any human.
Genetic engineers have already modified D. radiodurans for use in nuclear weapons manufacturing. Perhaps now they can build on a footnote from the mid-1950s search for peaceful uses of nuclear energy to clean up some of the fallout from the peaceful use of nuclear energy.
Sources
- The Virtual Museum of Bacteria, online at BacteriaMuseum.org.
- Brim H, McFarlan SC, Fredrickson JK, Minton KW, Zhai M, Wackett LP, Daly MJ. "Engineering Deinococcus radiodurans for metal remediation in radioactive mixed waste environments." Nature Biotechnology (Jan 2000) 18(1): 85-90.
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