The researchers, Ashleigh Kropp (left) and Dr. Rhys Grinter, helped discover the new Huc enzyme. (Image Credit: Monash University)
Monash University researchers recently discovered Huc, a new enzyme that converts air into electricity. According to their study, Huc "uses the low amounts of the hydrogen in the atmosphere" to generate an electrical current. This discovery could pave the way for developing electronics that generate power from the surrounding air.
The team created and analyzed this enzyme from a common soil bacterium. They also demonstrated that most bacteria consume hydrogen in the atmosphere for energy in areas with insufficient nutrients. "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," Professor Chris Greening said. "But we didn't know how they did this until now."
The team extracted the enzyme from the Mycobacterium smegmatis bacterium and proved that it transforms hydrogen into an electrical current. "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," Dr. Rhys Grinter explains.
"(a) Motion-corrected micrographs of vitrified purified Huc oligomers, showing Huc associated with membrane vesicles (left panel) and free Huc (right panel). (b) Selected 2D class averages of Huc oligomer, showing C4 symmetry and flexible membrane-associated stalk. (c) Data processing workflow for the Huc oligomer reconstruction. (d) The Euler angle distribution of particles used for Huc oligomer reconstruction. (e) Gold-standard Fourier shell correlation (FSC) curves calculated from two independently refined half-maps indicate an overall resolution of 2.19 Å at FSC = 0.143, and Guinier plot indicates a sharpening B-factor of 57.2. (f) A local resolution map of the Huc oligomer, showing a resolution range of ~1.8 to 4.8 Å from the Huc core to the periphery, indicative of significant interdomain motion." (Image and Caption Credit: Monash University)
The team used numerous advanced techniques to unveil the molecular blueprint of atmospheric hydrogen oxidation. They used advanced microscopy (cryo-EM) to determine its atomic structure and electrical pathways. Electrochemistry also demonstrated that the purified enzyme produces energy at minute hydrogen concentrations.
According to Ph.D. student Ashleigh Kropp, Huc can be stored for a long 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," Kropp said. "This reflects that this enzyme helps bacteria to survive in the most extreme environments."
Huc works as a natural battery generating an electrical current from the air or additional hydrogen. Although the work is in the early stages, Huc could be used to develop air-powered devices. Researchers can grow large amounts of the bacteria that produce enzymes like Huc. "Once we produce Huc in sufficient quantities, the sky is quite literally the limit for using it to produce clean energy," says Dr. Grinter.
Have a story tip? Message me at: http://twitter.com/Cabe_Atwell