Novel device can generate electricity from air using bacterial protein: Study

Boston: Researchers have developed a new device that uses a natural bacteria-derived protein to create electricity from moisture in the air, an advance that may help produce renewable energy that can work indoors unlike solar and wind-based generators.

The device, described in the journal Nature, is called "Air-gen", or air-powered generator, and is made using ultrasmall electrically conductive protein wires produced by the microbe Geobacter which was discovered in the mud of the Potomac River in the US more than 30 years ago. According to the researchers from the University of Massachusetts (UMass) Amherst in the US, Air-gen connects electrodes to the tiny protein wires in such a way that it generates electrical current from water vapour naturally present in the atmosphere. "We are literally making electricity out of thin air. The Air-gen generates clean energy 24/7," said Jun Yao, study co-author from UMass Amherst. The device, the scientists said, is non-polluting, renewable and low-cost. They added that it can generate power even in areas with extremely low humidity such as the Sahara Desert. According to Derek Lovely, another co-author of the study from UMass Amherst, the device has significant advantages over other forms of renewable energy including solar and wind since "it even works indoors." Air-gen requires only a thin film of tiny protein wires which are less than 10 micrometres thick and absorb water vapour from the atmosphere, the scientists said. The bottom of the film, they added, rests on an electrode, while a smaller electrode that covers only part of the protein wire film sits on top. With peculiar surface chemistry features, and the ability to conduct electricity, these tiny protein wires and the fine pores between them, establish conditions favourable for generating an electrical current between the two electrodes, the study noted. The scientists hope to scale up the technology to power small electronics. "The ultimate goal is to make large-scale systems. For example, the technology might be incorporated into wall paint that could help power your home. Or, we may develop stand-alone air-powered generators that supply electricity off the grid," Yao said. "Once we get to an industrial scale for wire production, I fully expect that we can make large systems that will make a major contribution to sustainable energy production," he added. The scientists recently engineered a new microbial strain to more rapidly and inexpensively mass produce the protein wires. "We turned E. coli into a protein nanowire factory. With this new scalable process, protein nanowire supply will no longer be a bottleneck to developing these applications," Lovely said.