Researchers at the Stevens Institute of Technology in New Jersey have come up with an unexpected way to produce electricity without using fossil fuels: A mushroom covered with bacteria. The “bionic mushroom” was announced in the journal Nano Letters and has captured the imagination of the public due to its wacky creativity.
Bacteria have been of interest to energy researchers for years due to their ability to generate oxygen, process oil spills, and generate electricity. However, the cyanobacteria in question here have proven difficult to work with because they cannot survive for long enough on artificial surfaces to be useful for power generation. The breakthrough came when scientists considered using a common button mushroom like those you find in the grocery store as a surface for the bacteria. Mushrooms naturally have an ecosystem of bacteria living on them so they provided the perfect home for the cyanobacteria to thrive.
The basis for the mushroom generator is the observation that bacteria and fungi like mushrooms often live in a state of symbiosis where both lifeforms benefit each other. With the refinement of 3D printing technology, it is now possible to produce tiny materials which interact on a microscopic scale. This means that bacterial cells could be affixed to the mushroom with a net of 3D printed nanoribbons that are spiraled over the mushroom cap. The combination of bacteria and mushroom enables a process called “photosynthetic bioelectricity generation,” which is a fancy way of saying that when researchers shone a light onto the bacteria, it produced a tiny amount of electricity.
As the amount of electricity produced is small, in order to be effective at a practical scale, a whole series of mushrooms would be required. With several mushrooms wired together, enough electricity could be produced to light a small lamp. Researcher Dr. Sudeep Joshi, a postdoc in the Department of Instrumentation and Applied Physics at the Indian Institute of Science, told BBC News: “We are looking to connect all the mushrooms in series, in an array, and we are also looking to pack more bacteria together… These are the next steps, to optimize the bio-currents, to generate more electricity, to power a small LED.”