An enzyme that turns air into energy has been discovered by Australian researchers. The finding, which came out today in the journal Nature, shows that this enzyme uses a small amount of hydrogen in the atmosphere to generate an electric current. This discovery makes it possible to design electronics that effectively generate electricity out of thin air.

Researchers from the Monash University Biomedicine Discovery Centre in Melbourne, Australia, lead by Dr. Rhys Grinter, PhD student Ashleigh Kropp, and Professor Chris Greening, cloned and characterized an enzyme from a common soil bacteria that consumes hydrogen.

In nutrient-poor settings, many bacteria utilize atmospheric hydrogen for energy. 

“We’ve known for some time that bacteria can use the trace hydrogen in the air as a source of energy to help them grow and survive, including in Antarctic soils, volcanic craters, and the deep ocean” adds Professor Greening. “But we didn’t know how they did this, until now.”

In this study published in Nature, scientists isolated an enzyme from Mycobacterium smegmatis that allows the bacteria to use hydrogen from the air. They demonstrated how the Huc enzyme converts hydrogen gas into an electrical current. 

Dr. Grinter remarks “Huc is extraordinarily efficient. Unlike all other known enzymes and chemical catalysts, it even consumes hydrogen below atmospheric levels – as little as 0.00005% of the air we breathe.”

Researchers used a number of cutting-edge techniques to figure out the molecular blueprint of hydrogen oxidation in the atmosphere. They used advanced microscopy (cryo-EM) to figure out its atomic structure and electrical pathways. By pushing the limits of this method, they were able to get the most detailed structure of an enzyme ever reported using this technique. They also used a method called “electrochemistry” to show that the purified enzyme makes electricity when there is a very small amount of hydrogen present.

Ms. Kropp has shown in the lab that pure Huc may be kept for extended periods of time. 

“It is astonishingly stable. It is possible to freeze the enzyme or heat it to 80 degrees celsius, and it retains its power to generate energy,” Ms. Kropp adds. “This reflects that this enzyme helps bacteria to survive in the most extreme environments.”

Huc is a “natural battery” that uses air or hydrogen to generate a steady electrical current. While still in its infancy, this study’s discovery of Huc has great promise for the advancement of tiny air-powered gadgets, which might serve as an alternative to solar-powered electronics.

Bacteria that make enzymes like Huc are common and can be grown in large numbers, so we have a steady supply of the enzyme. Scaling up the production of Huc is a critical goal for future research, according to Dr. Grinter. 

“Once we produce Huc in sufficient quantities, the sky is quite literally the limit for using it to produce clean energy.”

Source: 10.1038/s41586-023-05781-7