Saturday, February 5, 2011

Arsenic-eating bacteria: Scientists discover new bacteria that cleans up polluted soils of arsenic

By Syed Akbar
Hyderabad: 3: In a major discovery that could solve the problem of arsenic poisoning in pollution hotspots including Patancheru in the city, scientists have found a new species of bacterium that eats away the highly lethal arsenic from the soils.
The new bacterium, announced by NASA on Wednesday, not only survives on arsenic but also incorporates the killer element into its genetic material. The discovery of arsenic-eating bacterium has been hailed by scientists in Hyderabad, and they hope that the problem of ground water and soil pollution by arsenic can be solved the "natural way".
"It is possible that the bacterium can bring down the arsenic to non-toxic levels. Once the arsenic levels in water and soil are brought down, arsenic can be obtained from the bacterium through bio-accumulation and extraction," senior CCMB scientist Dr S Shivaji, who also heads the Lacones project, told this correspondent.
Earlier, a team led by Dr Shivaji discovered three species of arsenic-tolerant bacteria from West Bengal and it named them as Bacillus indicus, B arsenicus and Deinococcus indicus. "We do not know how different the NASA-discovered bacterium is from the ones we had found out. But these bacteria can bring down the arsenic content to a less toxic level," he said.
Areas around Hyderabad, particularly Patancheru and Bolaram, are highly polluted with arsenic content going up to even 40,000 ppb (parts per billion) as against the permissible levels of just 50. A study by Jawaharlal Nehru University on arsenic pollution in industrial pockets of Hyderabad revealed that arsenic present in the soil form complexes with the organic acids such as fumic acid which help these pollutants to migrate faster through the soil and contaminate the aquifers. The decomposition rate of organic matter is very high in India as being a tropical country.
"The source of arsenic is not from natural rocks but from the industrial effluents brought by different industries. Water samples from Peddavagu and Nakkavagu streams are showing high arsenic concentration of up to 5,000 ppb. Ground water samples from some of the villages like Bandalguda, Muthangi and Patelgudem have high concentration of arsenic. In some of the wells the arsenic concentration was found to be 750 ppb," the JNU report said.
The researchers, funded by NASA, isolated bacteria from the mud of Mono Lake in eastern California which has a high concentration of arsenic. "May be Patancheru and other industrial areas have arsenic-thriving bacteria. We need to conduct research to find out," Dr Shivaji said.
Scientists know that some microbes can breathe arsenic, but what the NASA team has found is a microbe doing something new - building parts of itself out of arsenic. The results of this study will inform ongoing research in many areas, including the study of Earth's evolution, organic chemistry, biogeochemical cycles, disease mitigation and Earth system research. These findings also will open up new frontiers in microbiology and other areas of research.

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