Science  02 Mar 2012:
Vol. 335, Issue 6072, pp. 1026
  1. Genetically Engineered Bacteria Could Help Fight Climate Change

    Some researchers believe that capturing atmospheric CO2 and trapping it in buried rocks could lower the risk of catastrophic climate change. Now researchers have found that bacteria can speed that process up.

    CO2 pumped into underground rocks combines with metal ions in the salty water that fills the rock pores and mineralizes into mineral carbonates such as calcium carbonate (CaCO3). That can take thousands of years. To see if they could speed things up, biochemist Jenny Cappuccio and colleagues at the Lawrence Berkeley National Laboratory's Center for Nanoscale Control of Geologic CO2 put a mix of common bacterial species in a calcium chloride solution in the lab and pumped in CO2. They found that calcium carbonate formed faster where the bacteria were living than in sterile solutions.

    Taking shape.

    Initially amorphous in sterile solutions (left), calcium carbonate quickly forms crystals (right) when bacteria are present.


    The team guessed that the surfaces of the bacteria were helping the CO2 hook up with calcium ions. They modified one of the bacterial species, Caulobacter vibrioides, inserting a sequence of DNA that reshaped the bacteria's surface to attract calcium ions.

    It worked. When the researchers pumped CO2 into the tanks where the modified bacteria were living, even more CaCO3 solidified than in tanks with unmodified bacteria. Cappuccio reported the team's results 26 February at a meeting of the Biophysical Society in San Diego, California.

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