Xylanases: For sustainable bioproduct production

Agricultural waste, the most abundant renewable resource, has gained importance as promising feedstock for the production of biofuels and biobased solvents (butanol, acetone) and enzymes. Enzymatic hydrolysis of hemicelluloses requires synergistic action of multiple enzymes, among them endo-1,4-xylanases (EC. 3.2.1.8) and β-xylosidases (EC 3.2.1.3), collectively known as xylanases, play a major role in the hydrolysis of xylan, the major component of hemicellulose. Though much of research in the past 10-15 years has been on developing technologies for utilization of hemicelluloses, an industrially viable process for commercial production still remains as a major challenge. Xylanases have wide applications in industry. They are used as additive in poultry field, enzyme preparation for hydrolysis of hemicelluloses for bioethanol, biobutanol production, biobleaching of wood pulp in paper industry, food additive in baking industry, and one of ingredient in detergents. This book chapter mainly discusses on recent progress in xylanase production and application with emphasis on heterologous expression, consolidated bioprocessing (CBP) for direct conversion of biopolymers to bioproducts, protein engineering approaches like site-directed mutagenesis, and metabolic engineering of host systems with significance on industrially viable xylanase production.