The invention relates to enzymes having xylanase, mannanase and/or glucanase activity, e.g., catalyzing hydrolysis of internal .beta.-1,4-xylosidic linkages or endo-.beta.-1,4-glucanase linkages; and/or degrading a linear polysaccharide beta-1,4-xylan into xylose. Thus, the invention provides methods and processes for breaking down hemicellulose, which is a major component of the cell wall of plants, including methods and processes for hydrolyzing hemicelluloses in any plant or wood or wood product, wood waste, paper pulp, paper product or paper waste or byproduct. In addition, methods of designing new xylanases, mannanases and/or glucanases and methods of use thereof are also provided. The xylanases, mannanases and/or glucanases have increased activity and stability at increased pH and temperature.
STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH
 This invention was made in part with Government support under Contract No. DOE 1435-04-03-CA-70224, awarded by the Department of Energy. The Government may have certain rights in the invention.