This article is a couple of years old, but with the soaring cost of gas deserves a second look:
Bacteria Engineered to Turn Carbon Dioxide Into Liquid Fuel
Bacteria Engineered to Turn Carbon Dioxide Into Liquid Fuel
In a new approach, researchers from the UCLA Henry Samueli School of Engineering and Applied Science have genetically modified a cyanobacterium to consume carbon dioxide and produce the liquid fuel isobutanol, which holds great potential as a gasoline alternative.