There's a fuel called Butanol that can be produced by fermenting the same feedstocks used to produce ethanol in about the same volume, except it's energy content is much closer to gasoline and you can get away with using it (Bu100) in a normal gasoline burning engine. Not much research has been done in the past because ways were found to manufacture it from petroleum, so that took it out of the market as any sort of bio-fuel until now, when we're looking for the best solution to our liquid fuel addicted lifestyle... Some infos:
http://www.greencarcongress.com/2005...ng_biomas.html