Xylanase Production by Isolated Fungal Strain, Aspergillus fumigatus RSP-8 (MTCC 12039): Impact of Agro-industrial Material as Substrate

In the present investigation, the imperative role of agro-industrial biomass for improved xylanase production was evaluated using isolated fungal strain. This isolate was identified as Aspergillus fumigatus RSP-8 (MTCC 12039) based on morphological and 18S rRNA ribotyping and the organism was deposited in MTCC, IMTECH Chandigarh with accession number 12039. The isolated fungal strain is mesophilic in nature and produced maximum xylanase at 30 °C, at pH 7 and agitation speed of 150 rpm. Xylanase complex production titers differed with the nature and complexity of carbon source and other physiological growth parameters including aeration, growth temperature, physiological medium pH, initial inoculum levels, etc. Highest xylanase titers (73 U/mL) noticed with hemicellulose isolated from sorghum straw and least with ground nut cake as carbon source among tested agro materials such as rice bran, green gram husk, sorghum straw, groundnut cake and wheat bran. A variation of three fold enzyme titers was observed with different tested carbon sources. Supplementation of glucose as carbon source did not produce any xylanase with this fungal strain revealing the xylanase in this isolate is induced by the carbon source. Variation of hemicellulose concentration as carbon source during the fermentation altered the production xylanase titers. The study suggested that, in xylanase production by A. fumigatus RSP-8, one of the major limiting factors is substrate chemical complexity