Scientists have discovered a fungus that makes what they call myco-diesel, actually a collection of medium chain hydrocarbons.  Plenty of organisms making short and long chain HC, but this is the first significant amount of burnable medium chain HC.  Some of the problems include condensing the HC vapor produced by the fungus to a liquid, and of course scalability for production, but it's a step in the right direction, and this fungus can eat the waste of pretty much every agriculture facet I can think of.   Once they find the gene that makes this possible it'll probably be on to our favorite e.coli to finish the job.  And since the process is using plants that got carbon from the atmosphere and not from something that's been locked in the ground for millions of years(coal and oil), it's carbon neutral.  I sure hope they can get THIS straightened out.  Then we can all drive around with reactors on our cars full of bacteria and fungus, and feed it whatever we can find, just like Doc.