A new bionic leaf could soon allow the manufacture of environmentally-friendly fuels through the use of bacteria, similar to methods employed by plants. Vegetation around the world harvests sunlight, allowing the life forms to process water and components in the atmosphere into food, supplying their life processes.

Harvard University researchers have now developed a new system which utilizes a type of bacteria to convert solar radiation into a form of liquid fuel, which could be used to power motor vehicles.

Photovoltaic cells can already be used to produce hydrogen, which can be stored in fuel cells, and later used to power vehicles. However, hydrogen fuel cells have not yet gained mainstream acceptance anywhere in the world, limiting the usefulness of the technology.

An artificial leaf was previously developed by Daniel Nocera of Harvard University, who also participated in the new project. The new bionic leaf uses some of the technology developed during that earlier research, which also inspired the name.

"This is a proof of concept that you can have a way of harvesting solar energy and storing it in the form of a liquid fuel. Dan's formidable discovery of the catalyst really set this off, and we had a mission of wanting to interface some kinds of organisms with the harvesting of solar energy. It was a perfect match," Pamela Silver of the Wyss Institute, said.

Hydrogen produced by an artificial leaf is fed into a container of Ralstonia eutropha bacteria. The gas is converted into protons and electrons, through the actions of an enzyme. These particles then combine with carbon dioxide, assisting in the reproduction of the bacteria, and production of fuel.

This new discovery could pave the way to a future where fuels are produced locally, eliminating the need to transport fuel over great distances.

Similar technology could also be used to produce a wide range of drugs, including vitamins, potentially reducing malnutrition throughout the world. The technique could also be used to produce other chemicals which could benefit communities and businesses.

Plants have an average efficiency of around one percent in converting solar energy into biomass, but the goal of Silver and her team is to reach levels five times that high.

"We're almost at a 1 percent efficiency rate of converting sunlight into isopropanol. There have been 2.6 billion years of evolution, and Pam and I working together a year and a half have already achieved [that] efficiency of photosynthesis," Nocera told the press.

Development of the new bionic leaf was profiled in the journal Proceedings of the National Academy of Sciences.