Gold-mining bacterium discovered by McMaster researchers


Research out of McMaster University has discovered a species of bacteria that can turn water-soluble gold into the precious metal’s solid form.

A paper published online this month in Nature Chemical Biology showed that the microorganisms, called Delftia acidovorans, convert the gold to protect themselves from the metal’s soluble form, which is toxic.

The bacteria had been recently observed on the surface of tiny pieces of solid gold, so the researchers wanted to investigate what the connection was.

“Soluble gold is toxic to life and so it was thought that the bacteria was part of the process to turn the soluble gold into solid gold,” Nathan Magarvey, one of the researchers from McMaster, explained.

As they discovered, they were right.

“Basically, this little, unseen bug is using a small amount of chemical, which reacts with the gold ions and subsequently the gold becomes [solid].”

It’s not uncommon for bacteria to affect or change their environment in this way, according to Magarvey, but this is the first organism discovered to have this effect on gold.

He said while the idea of a tiny organism essentially creating gold is exciting for many, for the researchers involved, the big interest was in being able to discover a new chemical and clearly define how it works.

“For us, that’s the satisfaction,” he said, adding that they are looking at the potential to produce this chemical on a larger scale. This could allow miners to retain more gold from the soluble form.

But Magarvey stressed it’s a little too early to proclaim they’ve discovered the Midas touch.

“There are some big dreamers out there, but we’re practical here,” he said.

“It may capture the imagination and people might think that we’re making blocks of gold on campus. But, we’re not.”

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