[Caleb (OP)]

I was listening today on my recorder to a previous Naked Scientist show on bacteria that have been modified to extract CO2 out of coal fired power plants. The impact seems huge!

Can this possibly be the start of a world saver? Ponds of this type of bacteria extracting CO2 from the air (and perhaps being only able to live in a certain medium, etc., so it can't escape)?

Very, very impressive story -- as they pretty much all are!

Yours,

Caleb

[CliffordK]

Any "extraction" of CO₂ requires energy. 

This could be chemical energy, but that puts one back to the same place of needing a energy. 

The most common energy source for living organisms to extract CO₂ is sunlight.  Organisms can be just about any, but some of the hottest research is with either algae (small single celled eukaryote), or perhaps cyanobacteria (single celled bacteria). 

One would still need to determine what to do with the algae or cyanobacteria once produced.  The most likely things would be food, feed, or fuel.  I.E.  Something that will put it back into the energy cycle. 

As fuel, it is only effective if it replaces a significant amount of solid or liquid fuel.