The industrial enzyme market approaches approximately one billion US dollars annually. Several enzymes have already become commodity chemicals for many industrial application purposes such as in the production of various com syrups and sweeteners and fuel ethanol from starch. Right now, the market for the enzymes involved in various lignocellulosic biomass conversion is limited and depends entirely on their use in the conversion of various lignocellulosic feedstocks to fermentable sugars for the subsequent production of fuel alcohols and value-added chemicals. Currently, cellulolytic enzymes are expensive and their hydrolysis rates are very slow. The development of an environmentally compatible highly efficient enzyme system free from product and substrate inhibitions for conversion of various pretreated agricultural residues to glucose is very important for use of these materials for production of fuel alcohol. The market for these enzymes will expand rapidly if certain properties of them can be improved and if these enzymes are made available for biomass conversion at a competitive price like starch degrading enzymes. On the other hand, the development of a very efficient substrate pretreatment that increases the susceptibility of crystalline cellulose to enzymatic hydrolysis significantly will lower the cost of producing ethanol from lignocellulosic biomass.