Scientists from the Department of Chemical Engineering and Materials Science at Michigan State University (MSU, United States) have reported the use of a biomass pretreatment process which can help reduce the cost of cellulose ethanol production. The purpose of pretreatment is usually to remove the tight lignin wrapping around the plant cellulose fibers, and to liberate the cellulose for facilitated enzymatic breakdown into simple sugars. The simple sugars are then fermented to ethanol. Conventional pretreatment methods usually involve the use of acids or steam under high temperature or pressure, and often require large amounts of process water to detoxify the liberated cellulose material by repeated washings. Nutrient supplementation of the material for ethanol fermentation is also needed. The MSU scientists found that the use of a pretreatment process called “Ammonia Fiber Expansion” (AFEX), could obtain a material (delignified cellulose) which does not require additional water for detoxification. The material also does not require nutrient supplementation during ethanol fermentation. This would result in significant reduction in production cost of cellulose ethanol. The researchers published their findings in a recent issue of the Proceedings of the National Academy of Sciences (PNAS) (URL above)..