Turning CO2 emissions into plastic with algae? It may not be as crazy as it sounds

[Bill USA]

http://www.eenews.net/stories/1060023524

Jianping Yu, a research scientist with NREL's Photobiology Group, is leading a team of researchers who are working with these organisms. In his lab, they have been able to make ethylene directly from genetically modified algae.

The researchers were able to accomplish this by introducing a gene that coded for an ethylene-producing enzyme -- effectively altering the cyanobacteria's metabolism. This allows the organisms to convert some of the carbon dioxide normally used to make sugars and starches during photosynthesis into ethylene. Because ethylene is a gas, it can easily be collected.

Making ethylene doesn't require many inputs, either. The basic requirements for cyanobacteria are water, some minerals and light, and a carbon source. In a commercial setting, CO2 could come from a point source like a power plant, Yu said.

If this alternative production method becomes efficient enough, it could potentially replace steam cracking, the energy-intensive method currently used to break apart petrochemicals into ethylene and other compounds. Because the algae take in three times the CO2 to produce a single ton of ethylene, the process acts as a carbon sink. That would be a significant improvement over steam cracking, which generates between 1 ½ and 3 tons of carbon dioxide per ton of ethylene, according to the researchers' own analysis. The captured ethylene gas can then be transformed for use in a wide range of fuels and products.
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