LOS ANGELES, Dec. 7 (Xinhua) -- A process to produce lower-cost, renewable biofuels has been developed by researchers at the Arizona State University (ASU).

    Researchers have programmed a photosynthetic microbe to self-destruct, making the recovery of high-energy fats and their biofuel byproducts easier and potentially less costly.

    The results were published in the Dec. 7 issue of the Proceedings of the National Academy of Sciences.

    Roy Curtiss, director of the Biodesign Institute's Center for Infectious Diseases and Vaccinology and professor in the School of Life Sciences, said the real costs involved in any biofuel production are harvesting the goodies and turning them into fuel.

    "This whole system that we have developed is a means to a green recovery of materials not requiring energy-dependent physical or chemical processes," Curtiss stressed.

    Researchers at ASU have been focusing on optimizing photosynthetic microbes, called cyanobacteria, as a source of renewable biofuels.

    These microbes are easy to manipulate genetically and have a potentially higher yield than any plant crops currently being used as transportation fuels.

    However, until now, harvesting the fats from the microbes is very expensive. Cyanobacteria have a multi-layer protective set of outer membranes that help the bacteria thrive even in harsh surroundings, creating the pond scum often found in swimming pools.

    Curtiss and postdoctoral researcher Xinyao Liu placed a suite of genes into photosynthetic bacteria that were controlled by the simple addition of trace amounts of nickel to the growth media to get the cyanobacteria to more easily release their precious, high-fat cargo.

    Liu said genetics is a very powerful tool. They have created a very flexible system that they can finely control.

    According to the researchers, the genes were taken from a mortal bacterial enemy, called a bacteria phage, which infect the bacteria, eventually killing the microbes by causing them to burst like a balloon.

    Researchers swapped parts from bacteria phages that infect E. coli and salmonella, and simply added nickel to the growth media, where the inserted genes produced enzymes that slowly dissolved the cyanobacteria membranes from within.

    According to Curtiss, this is the first case of using this specialized bacterial system and placing it in cyanobacteria to cause them to self-destruct.

    Curtiss, a pioneer in developing new vaccines, has filed a patent with Liu on the technology.

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