There’s a pretty good piece over on wired.com about a company that’s developed a strain of bacteria they claim can produce fuel at around $1 a gallon using non-food biomass as the source. It’s pretty interesting and one of the most promising of all the alternative schemes I’m aware of. The article fails to mention that a gallon of ethanol contains much less potential energy than a gallon of gas, but even so based on the comparisons between corn and switch grass based ethanol production this process looks really promising.