Generating electricity from air? Scientists discover energy enzyme

A new source of clean energy

For many years, researchers have known that bacteria living in nutrient-poor regions turn to hydrogen from the atmosphere as a source of energy. This has been observed in extreme environments such as the Antarctic soils, volcanic craters, and in the depth of oceans. However, the exact mechanism of how they tap into hydrogen was not known.

The researchers at Monash University's Biomedicine Discovery Institute then turned to a common soil bacterium, Mycobacterium smegmatis, to probe into this further and extracted an enzyme called Huc, which can convert hydrogen gas into an electric current.

They then used the most advanced techniques to find out more about the structure and function of the enzyme. Methods like cryo-electron microscope (cryo-EM) were used to determine the molecular structure of the enzyme while electrochemistry was used to demonstrate that the enzyme could work even in minute concentrations of 0.00005 percent in the air.

The researchers also found that in its purified form, the enzyme was very stable and could survive extreme temperatures too. Laboratories usually freeze enzymes at temperatures below zero degrees Fahrenheit (-20 degrees Celsius) to keep them stable. The researchers found that the Huc enzyme could remain stable at temperatures as high as 176 degrees Fahrenheit (80 degrees Celsius) too and produce electricity when hydrogen was available.

The researchers have dubbed the enzyme a "natural battery" that can produce sustained electrical current using hydrogen. This is likely to lead to the development of small air-powered devices that will generate electricity.

While new technologies need multiple innovations before they can be scaled, the Huc enzyme is found in organisms that are abundant in the soil and can also be grown in large quantities to multiple many devices at once.

The research findings were first published in the journal Nature.