'Bacteria Turn Sunlight to Liquid Fuel in 'Bionic Leaf'
Researchers have paired a solar-powered catalyzing device with genetically engineered bacteria to convert water and carbon dioxide into an alcohol-based liquid fuel. The system, dubbed a "bionic leaf," is described in the Proceedings of the National Academy of Sciences.
The process is modeled after the way in which plants use photosynthesis to turn CO2, H2O and other ingredients into energy, but with some novel chemical twists. One of the researchers, Harvard's Dan Nocera, has been working on artificial leaf systems for more than a decade. "The catalysts I made are extremely well-adapted and compatible with the growth conditions you need for living organisms like a bacterium," Nocera said in a news release.
The catalyst uses sunlight to split water into hydrogen and oxygen. Then a strain of bacteria known as Ralstonia eutropha combines the hydrogen with carbon dioxide to make isopropanol — the main ingredient in rubbing alcohol.
Another member of the research team, Harvard Medical School's Pamela Silver, said the experiment was a "proof of concept" for solar-to-chemical conversion. The next step is to boost the system's energy efficiency rate from its current level of nearly 1 percent to a goal of 5 percent.
Strong as Titanium, Cheap as Dirt: New Steel Alloy Shines
The strength of steel is proverbial, but that doesn't mean it can't be improved. It's heavy, after all, and there are stronger metals out there. But researchers in South Korea have created an alloy that's as strong as titanium, lighter than ordinary steel, and cheap to boot. The new alloy, described in the journal Nature, is created by allying the steel with aluminum — this lightens the steel, but also makes it weak. To counter that weakness, the team added a dash of manganese and a sprinkle of nickel, while modifying the way the metal crystals form at the nanometer scale. This new alloy has no flashy name just yet but is referred to as High Specific Strength Steel. It has an even better strength-to-weight ratio than the far more expensive titanium. '