Xylanase production by Aspergillus awamori in solid-state fermentation andinfluence of different nitrogen sources

The use of purified xylan as a substrate for bioconversion into xylanases i ncreases the cost of enzyme production. Consequently, there have been attem pts to develop a bioprocess to produce such enzymes using different lignoce llulosic residues. Filamentous fungi have been widely used to produce hydro lytic enzymes for industrial applications, including xylanases, whose level s in fungi are generally much higher than those in yeast and bacteria. Cons idering the industrial importance of xylanases, the present study evaluated the use of milled sugarcane bagasse, without any pretreatment , as a carbo n source. Also, the effect of different nitrogen sources and the C:N ratio on xylanase production by Aspergillus awamori were investigated, in experim ents carried out in solid-state fermentation. High extracellular xylanolyti c activity was observed on cultivation of A. awamori on milled sugarcane ba gasse and organic nitrogen sources ( 45 IU /mL for endoxylanase and 3.5 IU/ mL for beta -xylosidase). Endosylanase and beta -xylosidase activities were higher when sodium nitrate was used as the nitrogen source, when compared with peptone, urea, and ammonium sulfate at the optimized C:N ratio of 10:1 . The use of yeast extract as a supplement to the these nitrogen sources re sulted in considerable improvement in the production of xylanases, showing the importance of this organic nitrogen source on A. awamori metabolism.