This book describes the study of xylanase enzyme chielfy about the characteristics of xylanase enzyme and effect of various substrates, temperature, pH on xylanase activity based on the standard quantitative assays, followed by an optimization of different parameters required for its industrial application, primarily in bio bleaching process of industry Kraft pulp, bio-pulping of wood; pulp bleaching for the production of eco-friendly products; processing food to increase clarification; treating animal feed to increase digestibility and many more.