Go directly to Thermal Depolymerization. Take all this cellulosic waste, chop it up finely, mix it into a water slurry, and put in in a sealed retort. Heat the retort to about 600 to 900 degrees F., maintaining a pressure of between two and five atmospheres, for about two hours.
Products will include a substance called kerogen and slightly saline water. In nature, this is EXACTLY how petroleum is formed, even though it may have been trapped in a resevoir for millions of years.
Depending on the conditions of temperature and pressure, plus the organic material put into the slurry, different grades of kerogen are produced. This process can be extended to a wide variety of organic materials, including many that are considered problematic sources of pollution.
Read an article in the April Motor Trend magazine yesterday that had the bio conversion of carbon based materials in EtOH. The proprietary process heated the biomass to make producer gas (CO + H2) which the bugs turned into EtOH. BTW, coke (from coal) and steam can also make producer gas. Author said EtOH could be made this way for about $1/gal.