Termites are proof that lignocellulose can be broken down into sugar components.  Those sugars can then be reformed into ethanol, or other biofuels.

 

The bacteria within the gut of the termite, and the symbiotic relationship that exists between the colonies of bacteria and the termite are key.

 

Humans aren't that different, the bacteria we hold within our systems is responsible for most of our digestive process.  Most of the DNA patterns we have within our bodies are non-human.

 

But if we can figure out how to breakdown the lignocellulose into sugars, like a termite, we'll flip the energy system completely.  Another huge game changer would be successfully and cheaply mimicking photosynthesis.