Although we normally relate the bacteria with diseases, the truth is that this group has a kind of ‘superpowers’ that range from ‘self-vaccination’ to eating plastic, to surviving in environments as hostile as space. They are also experts at getting energy almost out of thin air: scientists have long known that many are capable of generating electricity from the air in environments as hostile as volcanoes or the poles. However, the system they used for this was unknown. Now, Australian researchers have discovered the enzyme responsible for this ‘magical’ transformation, and say their finding is a first step towards creating natural batteries that produce clean energy.
The team, led by Rhys Grinter, Ashleigh Body and Chris Greening, researchers at Monash University’s Biomedical Discovery Institute in Melbourne, Australia, have already shown that many bacteria use hydrogen from the atmosphere as a source of energy in nutrient-poor environments; that is, just by ‘breathing’, even in hostile places for life, they generate electricity that helps them survive.
“We’ve known for some time that trace amounts of hydrogen in the air can be used by bacteria as an energy source to help them grow, including in Antarctic soils, volcanic craters, and the deep ocean,” Greening explains. “But we didn’t know how they did it. Until now”. The results of his new research have just been published in the journal Nature.
Huc’s secret
The team focused on an enzyme from the bacterium Mycobacterium smegmatis. Call Here, converts hydrogen gas into an electrical current. “Huc is extraordinarily efficient,” says Grinter. Unlike all other known enzymes and chemical catalysts, it consumes hydrogen below atmospheric levels, just 0.00005% of the air we breathe.”
The researchers used several methods to reveal the molecular model of the oxidation of atmospheric hydrogen. They used advanced microscopy (cryo-EM) to determine its atomic structure and electrical pathways, surpassing previously established limits to produce the most resolved enzyme structure reported by this method to date. They also used a technique called electrochemistry to demonstrate that the purified enzyme creates electricity at minute concentrations of hydrogen.
In the laboratory they also demonstrated that it is possible to store purified Huc for long periods. “It’s amazingly stable. You can freeze the enzyme or heat it to 80 degrees Celsius and it retains its power to generate energy,” Kropp explains. This reflects that this enzyme helps bacteria survive in the most extreme environments.”
Huc is anatural battery‘ which produces a sustained electric current from air or if hydrogen is added to it. The authors note that while this research is at an early stage, the discovery of this enzyme has “considerable potential to develop small air-powered devices, for example, as an alternative to solar-powered devices.”
Possibility of cultivation
The next question is obvious: where can we get more of this Huc that produces electricity out of thin air? The authors say that not only Mycobacterium smegmatis this enzyme is extracted: other common bacteria have similar enzymes and can be grown in large numbers, “meaning we have access to a sustainable source of the enzyme,” they note.
“Once we produce Huc in sufficient quantities, the sky is literally the limit for using it to produce clean energy,” Grinter notes.