Cellulosic materials are treated with Supercritical Carbon Dioxide in an extruder. Machine configuration and operating parameters are strictly controlled in a manner to enhance the ability of Supercritical CO2 to enter into the cells. This results in a controlled deterioration of the cell walls, increasing the reactivity of cellulose and also enhancing the rate and the extent of cellulose hydrolysis. This precisely controlled combination of pressure, shear & temperature accelerates the penetration of carbon dioxide molecules into the crystalline structures, thus more glucose is produced from cellulosic materials after the cell is destructurized as compared to those without the pretreatment increasing glucose yield by as much as 50%. Concurrent saccharification and fermentation tests also show the increase in the available carbon source from the cellulosic materials for fermentation to produce ethanol. As the system operates at low temperature, it will not cause degradation of sugars such as those treated with the high-temperatures involved in many systems discussed.
