Well, you can replace or part-replace gasoline with ethanol, and diesel with rapeseed oil (or even modified used chip oil), but would it work as a replacement for Avgas?
The Brazilians have been using gasohol (or bioethanol or whatever else you want to call it) for years to help their balance of payments - they get 4 crops per year of sugar cane, and you can ferment alcohol from anything with sugar in it. Cellulosic ethanol would come from plant waste, which you could make sugar from if you broke down the higher chain starches and cellulose into simpler sugars, presumably by heat and/or enzymes - it strikes me as a lot of messing around to produce large quantities of fuel, just that it sounds better to Richard.
Ethanol is a more efficient fuel than gasoline - it has a higer octane level, and lower emissions, and you can mix it in varying levels with gasoline or use it neat, with minimal changes to a typical gasoline engine, especially newer ones with fuel injection and good ECUs. It has the odd drawback as Steve points out, but as an organic replacement for gasoline it's very good. The problem here in the EU is that every politician and farmer thinks we'd turn the wine lake or oversubsidised sugar beet into ethanol for transport, but that would be ridiculously expensive.
I suspect that Embraer might have some answers as to whether ethanol or mixes of it with avgas may work in turbine engines! You would need an engine which could run on anything from 100% avgas to 100% ethanol depending on availability, though.