The metal-eating bacteria

It’s a strange diet, you have to admit that. But who judges bacteria? It all started with the curiosity of microbiologist Jared Leadbeater. After months of traveling to work, he returned to his office and found something strange. A manganese carbonate compound coated the items he had left in the sink. It was the first clue that discovered the metal-eating bacteria.

“I thought, ‘What’s this?'” Says Leadbeater, a researcher at the California Institute of Technology (Caltech). He realized that the manganese had been oxidized: it was manganese oxide now. He had lost his electrons. Who was the thief “I started to wonder if microbes that have been sought by science for decades could be responsible,” he says at Sciencealert.

The metal-eating bacterium has long been suspected. Now it has been found.
The metal-eating bacterium has long been suspected. Now it has been found.
Bacterial Detectives

Leadbeater and his team coated additional glasses with MnCO3 and sterilized some steam-sterilized. However, the manganese compound did not get darker (not even a year later). Therefore, the “thief” must be something that is destroyed by hot steam. They then carried out an RNA analysis, which revealed that 70 bacteria were present. Most were excluded until they had two possible culprits.

In particular, they were bacteria: Nitrospirae and Beta Proteobacterium. It is known that relatives of both types of bacteria live in the groundwater. “We isolate Betaproteobacterium from the modified oxides as individual colonies. This species did not oxidize MnCO3 alone. Either Nitrospirae is solely responsible for the oxidation of Mn or the activity is a consortium, “says the study. It was published in” Nature “.

The researchers used carbon-13-labeled manganese in some of their cultures. The bacteria built these carbon isotopes into their bodies. This confirmed that the suspected bacteria were autotrophic. That means they can make their own food using an energy source. In this case, the bacteria used the energy of the manganese electrons to convert the CO2 into usable carbon. How plants use sunlight to convert CO2 and water to sugar and oxygen during photosynthesis.

Manganese oxide analyzed under a microscope.
Manganese oxide analyzed under a microscope.
The truth in the pipes

This process is called chemosynthesis. Other metals are known to be used, but it is the first time that manganese is the fuel source. This element has a strange tendency to clog water pipes.

“There is a complete set of environmental literature on drinking water distribution systems clogged with manganese oxides,” said Leadbetter. But how and for what reason such material is produced is a mystery. Bacteria that use manganese to generate energy were thought to be responsible. Now we have the evidence.

The metal-eating bacteria could be useful for the production of manganese oxide. The close relatives of these species appear to be present in many places. You could generate amounts that match world reserves in just two years. Who knows: In the future, manganese oxide “made in bacteria” may be spoken of.

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