Indian Journal of Chemical Technology Vol. 20, July 2013, pp. 282-289 Optimization of xylanase production from Melanocarpus albomyces using wheat straw extract and its scale up in stirred tank bioreactor Gupteshwar Gupta 1, 2 , Vikram Sahai 2 & Rajinder K Gupta 1, * 1 University School of Biotechnology, Guru Gobind Singh Indraprastha University, Dwarka, New Delhi 110 078, India 2 Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology Delhi, New Delhi 110 016, India Received 1 November 2012; accepted 8 March 2013 Production of xylanase from agro-industrial by-product such as wheat straw has been optimized. The wheat straw is subjected to heat treatment under mild alkaline conditions for the extraction of xylo-oligosaccarides, which serve as both an inducer and a carbon source for fungal growth and xylanase production under submerged fermentation. The statistical approach of response surface methodology has been employed for the optimization of different nitrogen sources. The production of xylanase is influenced by the synergic effect of nitrogen sources in the fermentation medium. Further optimization of other factors such as inoculum age, inoculum size, initial pH, growth temperature and agitation significantly enhance xylanase activity to about 425 ± 5 IU/mL in shake flask using optimized fermentation medium and conditions. The scale up of fermentation process up to 14 L bioreactor yields a maximum xylanase activity of about 520 IU/mL in 36 h of fermentation which is 1.22-fold higher than that obtained at shake flask level. Keywords: Bioreactor, Melanocarpus albomyces, Response surface methodology, Submerged fermentation, Thermophilic fungus, Wheat straw extract, Xylanase Lignocellulosics, in the form of agricultural by-product, are most abundant and renewable complex natural carbon sources available in the form of plant biomass. Xylan, a heterogeneous polysaccharide, is an integral part of lignocellulosic structure consisting of -1,4 linked D-xylosyl residues 1 . Xylanases [EC.3.2.1.8] are responsible for the hydrolysis of xylan and subsequently releasing xylo-oligosaccharides in the form of xylose and xylobiose. The hydrolysed products in the form of soluble sugars have extensive range of biotechnological relevance in many fermentation processes and functional food industry 2 . Commercial use of xylan as a carbon source is uneconomical for the large scale production of xylanase, due to its high cost. Therefore, different natural substrates rich in lignocellulosic contents were evaluated for xylanase production 3 . Agricultural by-products containing hemicelluloses are generated globally and the use of agro-industrial by-products in biotechnological bioprocesses not only provide an alternative substrate but also help in solving some of the environmental pollution problems caused by their accumulation 4 . Different agricultural by-products used as carbon sources include corn cob 5 , corn cob and soya bean bagasse 6 , wheat straw 7 and wheat bran 8 . Under the submerged fermentation process, initial pretreatment of substrate facilitates the breakdown of complex lignocellulosic material into readily available carbon moiety either in insoluble or soluble form, which can be further utilized by the microbes for productivity enhancement. The pretreatment may include alkali extraction of corn cob 5 , rice straw 9 and the mixture of wheat straw and corn cob 10 . It was observed that the cultures respond better on alkali-treated rather than on acid-treated samples for enzyme production 11 . The awareness towards xylanase opens up the extensive variety of biotechnological applications in different range of industries. Xylanase plays an important role in bakery industry while preparing dough in bread making by providing better texture, loaf volume and shelf-life ultimately improving the quality of baked products 12 . The promising application of xylanase in pulp and paper industry makes this enzyme very energetic for its usage as bio bleaching of pulp. The enzyme supports, in increasing the brightness of pulp resulting in superior quality of paper and in turn, reducing or eliminating the use of chlorine, eventually help in reducing the environmental issues 13,14 . The use _______________ *Corresponding author. E-mail: rkg67ap@yahoo.com