13 January 2012
In Tackling Lead Pollution, Fungi May Be Our Friends
Fungi may be an unexpected ally in efforts to keep hazardous lead contamination under wraps. That’s based on the unexpected discovery by researchers at the University of Dundee that fungi can transform lead into its most stable mineral form.
The findings, reported in the journal Current Biology, suggest that this interaction between fungi and lead may be occurring in nature anywhere the two are found together. It also suggests that the addition or encouragement of fungi may be a useful treatment strategy for lead polluted sites.
'Lead is usually regarded as a pretty stable substance,' said Professor Geoffrey Gadd, of the College of Life Sciences at the University of Dundee. 'The idea that fungi and other microbes may attack it and change its form is quite unexpected.'
Lead is an important structural and industrial material but an unfortunate consequence of its popular use in everything from firearms to paint has been that lead contamination is a serious problem worldwide.
There have been efforts to contain lead in contaminated soils through the addition of a source of phosphorus, an element that enables the incorporation of lead into a stable pyromorphite mineral. But that change had been considered a purely chemical and physical phenomenon, not a biological one. That is, until now.
In the new study, the researchers carefully examined lead shot after it had been incubated with and without fungi. In the presence of fungi, the lead shot began to show evidence of pyromorphite formation after one month’s time.
That stable lead-containing mineral continued to increase in abundance with time. Minerals found on the surface of lead shot incubated without fungi represented less stable forms that resulted from normal corrosion.
'It seems the ability of many fungi to produce organic acids or other substances may be very important in attacking the lead and releasing forms of free lead including lead complexes, which can then react with phosphorus sources to form pyromorphite,' Professor Gadd explained.
While not all species of fungus are able to transform lead in this way, it appears many of them can, he added. It’s not entirely clear why some fungi do this, but it might assist their survival in contaminated soils.
The discovery is yet another example of the 'amazing things that fungi, and microbes more generally, can do in the environment," says Professor Gadd. "Even metals can be subject to microbial colonization and attack.'
NOTES TO EDITORS
LIFE SCIENCES AT DUNDEE
With more than 1000 staff and research students and external funding in excess of £30 million per year, the College of Life Sciences at the University of Dundee is one of the largest and most productive research institutes in Europe. Our reputation is genuinely global and is reflected in the fact that researchers in our laboratories represent no fewer than 58 different nationalities.
The University’s achievements in the life sciences were recognised with a double win at the 2011 Biotechnology and Biological Sciences Research Council Awards where Dundee was first for `Greatest delivery of impact'. The University is the central hub for a multi-million pound biotechnology sector in the east of Scotland, which now accounts for 16% of the local economy.
We collaborate with the world’s major pharmaceutical and biotechnology companies in the fight against diseases such as cancer, diabetes and rheumatoid arthritis. Our Drug Discovery Unit is actively developing drugs for the treatment of neglected tropical diseases including malaria and African sleeping sickness and translating innovative drug targets in oncology, eczema, type-2 diabetes, anti-bacterials and anti-virals. Our Microbiology and Plant Sciences research groups are involved in major environmental issues like the application of microbial systems for bioremediation of toxic metal and radionuclide pollution, and the development of new bio-fuels and bio-energy generation.
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