Pankaj Chauhan et al. 118 PRODUCTION OF XYLANASES BY ASPERGILLUS TERREUS UNDER LIQUID STATE FERMENTATION CONDITIONS Pankaj Chauhan 1 , Gaurav Kumar 2 and Aastha Jain 3 1 Department of cell Biology, 2 Department of Molecular Biology & Genetic Engineering, College of Biotechnology, S.V.P. University of Agriculture & Technology, Meerut. 3 Shobhit University, Meerut ABSTRACT Various parameters like pH, temperature, substrate concentration, incubation period and yeast extract concentration have been used in estimating the enzyme production by Aspergillus terreus. Incubation period was optimized on 8 th day of fungal inoculation at 6.0 pH, 40 0 C temperature and 2% wheat bran was used as substrate for optimum production of xylanase. Total 5 mg/ml phosphate buffer and birch wood xylan were taken as substrate at a pH of 6.5 and the temperature of 55 0 C for xylanase activity. Thus xylanase preparation by this fungus was optimum at 40 0 C and this enzyme was found to be thermophilic in nature. Lignocellulosic biomass is the most plentiful of all naturally occurring organic compounds. It includes materials like wood, herbaceous crops, agricultural and forest residues, waste paper and paper products and municipal solid wastes etc.. Some of these lignocellulosic residues were available at bagasse, rice, sunflower seed hulls and Eichhornia processing sites. Lignocellulosic material consists of cellulose (40-60%) with lesser but significant amount of hemicellulose (20-30%) and lignin (15- 30%). They constitute a renewable resource from which many useful feed and chemical products including fuels can be derived (4). For bioconversion of polysaccharides to fermentation products in lignocellulosic material, maximum utilization of polymeric sugars is desirable. Complete hemicellulolytic enzyme system is required to achieve maximum hydrolysis of complex substrates to yield monomeric sugars. In order to obtain high yield of sugars, the lignocellulosic material need to be pretreated before enzymatic hydrolysis. Sugars obtained in saccharification process can be further utilized for the production of xylitol, organic acids and other solvents by means of fermentation. Pentoses can also be used as substrate for the production of protein rich biomass (single cell protein) for microbes and various processes have been developed (5). Hemicellulose:- Hemicellulose is a renewable polysaccharide consisting of either pentoses (xylose, arabinose) or hexoses (glucose, mannose, galactose) as well as uronic acid. They function as the supporting substance in plants. Recent investigations indicate that two more types of sugar units which include xylans may exist in hemicellulose molecule and are comprised of 20-25% plant biomass on dry weight basis (5). Hemicellulose is degraded by the synergistic action of endo-1-4, β xylanase, exo 1- 4, β Xylanase and β Xylosidase. D xylose is the major product of the hydrolysis of hemicellulose from many plant materials, in which xylose can represent up to 34% (4). MATERIALS AND METHODS The present investigation was carried out in the Department of Microbiology C.C.S. University, Prog. Agric. 13(1) : 118–121 (2013) Society for Recent Development in Agriculture