I've read about the gas algea, very, very spiffy. There was some work done about 15 years ago with making an algae or fungus that could could be air scattered that would eat petrochem based plastics and rubbers. I'm not sure if DoD ever got anywhere with it, but that could be adapted to be used to recycle plastic garbage into fuel by the a process similiar to that of the smoke stack guys.

And it doesn't have to be ethanol. It could be methanol, which is what the pulp based process which have been mentioned would be producing. The down side is that methanol, while a better fuel, burns a little dirtier. But certainly not as bas as gasoline.