For the past eight years, researchers in the lab of Peidong Yang have been working on a hybrid system that combines bacteria and nanowires to capture the energy of sunlight and convert carbon dioxide and water into building blocks for organic molecules. Nanowires are thin silicon wires about one-hundredth the width of a human hair, used as electronic components, and also as sensors and solar cells.
In a new paper published in the journal Joule, the researchers report a milestone in packing these bacteria (Sporomusa ovata) into a “forest of nanowires” to achieve a record efficiency: 3.6% of the incoming solar energy is converted and stored in carbon bonds, in the form of a two-carbon molecule called acetate: essentially acetic acid, or vinegar.
“On Mars, about 96% of the atmosphere is CO2. Basically, all you need is these silicon semiconductor nanowires to take in the solar energy and pass it on to these bugs to do the chemistry for you,” said project leader Peidong Yang. “For a deep space mission, you care about the payload weight, and biological systems have the advantage that they self-reproduce: You don’t need to send a lot. That’s why our biohybrid version is highly attractive.”