The Alchemists Dream: Scientists Find Bacteria That Transforms Toxins Into Gold

The Nuggets can aggregate to the size of sand grains say, experts. It’s every Alchemists dream. If we take a quick read about Alchemy, we will come across the philosopher’s stone and a substance that could turn ordinary metals into precious metals, such as gold and silver. For a long time, finding this magical stone was the most sought-after goal in the world of alchemy, the medieval ancestor of chemistry. Now, a team of German and Australian scientists has managed to unveil the hitherto mysterious molecular process that allows a certain bacteria—the bacillus Cupriavidus metallidurans to digest toxic metals and turn them into gold. As noted by science alert, “the rod-shaped C. metallidurans was first found to poop gold nuggets back in 2009, when scientists discovered that it somehow manages to ingest toxic gold compounds and convert them into the element’s metallic form without any apparent danger to the organism itself.” “The results of this study point to their involvement in the active detoxification of gold complexes leading to the formation of gold biominerals,” lead researcher, geomicrobiologist Frank Reith said in 2009. According to the results of the new study, the bacteria, which lives mostly in soils with a high content of heavy metals, managed to adapt to highly toxic environmental conditions. “If an organism chooses to survive here, it has to find a way to protect itself from these toxic substances,” says co-author of the latest study, microbiologist Dietrich H. Nies from Martin Luther University Halle-Wittenberg in Germany. To avoid being poisoned by heavy metals which are deadly to other creatures, Cupriavidus metallidurans the metals and excretes microscopic gold nuggets. As well as gold, copper is introduced into C. Metadillurans and when the particles of one and another metal come into contact, a series of chemical processes take place. Cupriavidus metallidurans employ enzymes to shift the aggressive metals out of their cells and for copper; it uses an enzyme called CupA. However, the presence of gold makes things a bit more difficult note experts. “When gold compounds are also present, the enzyme is suppressed, and the toxic copper and gold compounds remain inside the cell,” says Nies. But, just as with Copper, the ‘Alchemsits Bacteria’ employs another enzyme which scientists have labeled CopA. Using CupA and CopA, the bacterium has the ability convert the copper and gold compounds into forms that are less quickly absorbed by the cell. “This assures that fewer copper and gold compounds enter the cellular interior,” explains Nies. “The bacterium is poisoned less, and the enzyme that pumps out the copper can dispose of the excess copper unimpeded.” Through the interaction of different enzymes, the bacteria retains in it’s inside the toxic compounds of both metals and molecularly transforms the compounds to secrete so-called secondary gold. Thus, the role of this bacterium in nature is decisive for the formation of this type of gold, which arises from the decomposition of primary gold, allowing scientists to unravel the biochemical cycle of the precious metal.

The research has been published in Metallomics. Featured image credit: Arrows point to gold particles on C. metallidurans (American Society for Microbiolo.

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References:

• https://www.sciencealert.com/bacteria-produce-gold-nuggets-cupriavidus-metallidurans
• https://www.ncbi.nlm.nih.gov/pubmed/19815503
• http://www.sciencealert.com/bacteria-helps-make-gold
• http://pressemitteilungen.pr.uni-halle.de/index.php?modus=pmanzeige&pm_id=2830
• http://pubs.rsc.org/en/Content/ArticleLanding/2018/MT/C7MT00312A#!divAbstract