Renewable petroleum to the rescue

THURSDAY, 31 MARCH 2011

It took hundreds of millions of years to generate the fossil fuels we now rely on so heavily, and there may be only another 50 years worth of supply left ^[1]. A renewable source of hydrocarbon fuel is therefore in great demand. Scientists funded by the U.S. Department of Energy are approaching the challenge using a combination of bacterial cultures. Firstly Synechococcus, a bacterium that is found widely in marine environments, is used to fix carbon dioxide in the presence of light and convert it to sugars, using the process of photosynthesis. The sugars can then be fed to Shewanella, a second bacterium that has been modified to transform fatty acids into ketones. This opens up the possibility of making petroleum-like hydrocarbon fuels ^[2]. Chemical engineers will then work on ‘cracking’ the thick hydrocarbon output to produce usable liquid transportation fuels.

There is considerable industrial interest in using carbon dioxide to make hydrocarbon fuels; the gas is freely available and is the major source of greenhouse gas, so removing it from the atmosphere would have beneficial environmental impacts. Furthermore, the same infrastructure for processing and transporting fossil fuels could be used for the new renewable fuel. The liquid hydrocarbons that the researcher’s propose to create will be clean-burning, so will not add carbon to the atmosphere and contribute to ozone depletion ^[3].

Written by Robert Jones

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