SCIENTISTS have engineered bacteria that can mop up mercury, a step towards using "bioremediation" to cleanse toxic chemicals from the environment.
Mercury pollution of water and soil by industrial spills or goldmining is a significant hazard because the chemical accumulates up the food chain, and tackling the problem is prohibitively expensive.
A team led by Oscar Ruiz of the Inter-American University of Puerto Rico said they inserted two mercury-friendly genes into the common intestinal germ, Escherichia coli. The genes controlled a protein called metallothionein and an enzyme known as polyphosphate kinase, both of which bind to metals to prevent toxicity in cells.
The researchers immersed the engineered bugs in a nutrient solution to which high doses of mercury had been added.After five days, the germs were spun in a centrifuge.Chemical analysis showed the bacteria had absorbed up to 80 per cent of the mercury to which they had been exposed, BMC Biotechnology reported.
Mr Ruiz said the work could lead to a way not only to clean up mercury but also to recycle it, using electrochemistry to extract the chemical from the bacteria.