Cupriavidus metallidurans is a unusual bacteria that was discovered years ago in Australia. C. Metallidurans has two large plasmids which bear a contain a wide variety of metal resistant genes. It has the ability to grow aerobically and is able to thrive in extreme environments and conditions. The habitat where C. metallidurans is most commonly found is in the general area where there are metals.  C. Metallidurans has the capabilities to biomineralise gold by changing the golds toxic compounds into a metallic form which is able to be used for active cellular mechanism. The results of the active cellular mechanism that C. Metallidurans is gold biominerals. This is what scientists conclude, to be the cause of gold nuggets and their larger sizes.
Researchers have also found that this ability to withstand high levels of toxicity is key in order to produce twenty-four karat gold. Previous reports of this bacteria had reported that it was twenty-five times less stronger than it was thought to be.  Scientists have used bioreactors in order to turn liquid gold into tangible twenty-four karat gold. This species of bacteria seems to be resistant to selenate and selenite. In the bacteria C. Metallidurans can transform selenate. 
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