The Greenest bike ever?

Just ran across this on the interwebs: http://esr.cc/mVRJIU

Ostensibly, it's quite a simple idea: Take the waste hydrocarbons from humans (and other animals, I assume) and turn it into Biogas. Now, I'm no expert, but I'm assuming this does not happen when you are on the motorcycle and the seat is therefore just an status thing. I'd also assume it needs more than one human to fill it up. Can you imagine the scene at the local gas station? "Sir, please come piss and/or poop in my fuel tank".

Either way, this contraption, built by Toto, will be taking in a month long tour of Japan shortly because it actually does run.

Either way, I can't see it being commercially viable just yet.