Bacteria As Alternate Energy? Cyanobacteria Converts Sunlight Into Fuel

By @rpalmerscience on

What do you imagine when you think of fossil fuel alternatives? A broad swath of solar panels or a field of pristine white turbines, perhaps -- but probably not a bucket of bacteria.

Researchers have found a possible way for renewable energy that’s quite literally green. Instead of relying on the energy bound up in the decomposing remains of organisms millions of years old, the fuel of the future could come from blue-green algae, or cyanobacteria.

In a paper published on Monday in the Proceedings of the National Academy of Sciences, scientists from the University of California, Davis, and Asahi Kasei Corporation in Japan described how they manipulated the bacteria to make a chemical that can be converted into fuels and plastics.

"Most chemical feedstocks come from petroleum and natural gas, and we need other sources," UC Davis chemist Shota Atsumi, co-author of the study, said in a statement Monday.

Cyanobacteria, like plants, use sunlight to power chemical reactions that convert carbon dioxide into energy they can use. Atsumi and his colleagues manipulated this natural machinery by inserting genes for certain enzymes into the bacteria. Eventually, the cyanobacteria were able to convert carbon dioxide into a chemical precursor called 2,3 butanediol.

The researchers managed to produce a peak production rate about 2.3 grams of the precursor for every liter of growth medium used, according to Wired.

Using bacteria to make alternative fuels would also not impact the food supply as much as other forms of biofuel, such as ethanol, the researchers say. Making ethanol from corn or switchgrass requires massive amounts of arable land to be used for growing fuel. And cyanobacteria don’t need to be fed on much other than carbon dioxide and sunlight.

“This work demonstrates that developing strong design methods can continue to increase chemical production in cyanobacteria,” the authors wrote.

The green dream of using photosynthesis to make renewable energy is not a new one, and some companies have already met with major hurdles in trying to scale up the process. One cautionary tale involves Massachusetts-based GreenFuel Technologies, which raised $70 million in funds after opening a facility in Arizona but shut down in 2009. GreenFuel may have primarily been slain by the recession, but the company also may have found it hard to keep up with the algae’s rapid growth rate.

But GreenFuel was using algae, which is different from cyanobacteria. Some scientists think cyanobacteria are easier to handle. Bacteria could prove to be the bug of choice for renewable energy in the future.

"You don't have a nucleus," Arizona State University microbiologist Wim Vermaas told the New York Times in 2009. "You don't have mitochondria. You don't have all the infrastructure to worry about. The volume is a thousand-fold smaller. The diameter is tenfold smaller. You really have properties you like."

SOURCE: Oliver et al. “Cyanobacterial conversion of carbon dioxide to 2,3-butanediol.” Proceedings of the National Academy of Sciences published online 7 January 2013.

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