Scientists have known for some time that a relative of the bacteria responsible for tuberculosis and leprosy could convert air into electricity, but it is only now that they have found out how, unlocking the potential for a clean energy source.
The team from Monash University found that the bacteria create hydrogen-consuming enzymes and are responsible for generating an electrical current from the air, The Independent reports. Professor Chris Greening from the university's Biomedicine Discovery Institute said these bacteria use the energy to grow and survive in harsh conditions in Antarctica, volcanic craters, and deep in the ocean.
Mycobacterium tuberculosis drug susceptibility test.
How the Enzyme Generates Electricity From Thin Air
The enzyme called Huuc is used by the bacterium Mycobacterium smegmatis to generate energy from atmospheric hydrogen. The bacteria are non-pathogenic and fast-growing, often used in the lab to study the cell wall structure of its pathogenic cousin, Mycobacterium tuberculosis.
Although its capability to use hydrogen from the air as an energy source is known widely in science, it is only now that scientists have begun to understand how. Live Science reported that the group first isolated the Huc enzyme using chromatography, a laboratory technique that allows scientists to separate the components of a mixture.
Then they investigated the atomic structure of the enzyme with the 2017 Nobel Prize-winning technique called cryo-electron microscopy. They beamed electrons onto a frozen sample of Huc enzyme gathered from M. smegmatis and then mapped out its atomic structure and electrical pathways that it uses to carry electrons to form electricity.
They found that Huc has a structure at its center known as the active site that contains charged nickel and iron ions. Once a hydrogen atom enters the active site, it is trapped between the nickel and iron ions and stripped of its electrons. The enzyme then sends these electrons to produce an electric current.
Researchers explained that electrons that Huc absorbs are transferred to its surface, and if the enzyme is immobilized on an electrode, the electrons can enter an electrical circuit from the surface and generate electricity.
Subsequent experiments also revealed that isolated Huc enzyme could be stored for long periods and survive heated or frozen temperatures. These attributes and its ability to be easily grown make the Huc enzyme an ideal candidate for a clean energy source, like organic batteries.
A Clean Energy Source for Portable Small Devices
A similar report by SciTech Daily says that Huc can act as a "natural battery" that generates a sustained electrical current from the air or added hydrogen. That means it could power a range of small portable electrical devices.
Although this potential technology is still early, its discovery could become an alternative to solar-powered devices. Researchers noted that the bacteria's ability to be produced in large quantities makes the sky the limit to producing energy.
They discussed the findings of their study, titled "Structural Basis for Bacterial Energy Extraction From Atmospheric Hydrogen," published in the journal Nature.
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