The production of cellulose-ethanol from lignocellulosic biomass usually takes four main processing steps: (1) “Pretreatment”, where the cellulose fibers are liberated from the tough “lignin wrapping” in the plant biomass, (2) “Saccharification”, where the liberated cellulose fibers are broken into simple sugars, (3) “Fermentation”, where microorganisms (usually yeasts) convert the simple sugars into ethanol, and (4) “Distillation”, the thermal separation of high purity ethanol from the fermentation broth. A recent review paper by Bin Yang and Charles Wyman (in the journal “Biofuels, Bioproducts and Biorefining”) mentions that the pretreatment step is “projected to be the single, most expensive processing step, representing about 20% of the total cost”. The use of chemical agents is said to “offer the high yields and low costs vital to economic success”. The review paper lists the following chemical pretreatments as the “most promising”: dilute acid, sulfur dioxide, near-neutral pH control, ammonia expansion, aqueous ammonia, and lime, with significant differences among the sugar-release patterns”. There is a need to improve knowledge of pretreatment systems to “substantially reduce costs and to accelerate commercial applications”..