Abstract

ISOLATION OF XYLANASE FROM ASPERGILLUS NIGER USING SOLID STATE FERMENTATION

P. V. Kamala Kumari*, Y. Srinivasa Rao and V. Bhavana

ABSTRACT

There exists a variety of xylanolytic enzymes and many micro-organisms produce multiple xylanases. [1, 2, 3] The prerequisites for efficient production of xylanolytic enzymes are the choice of an appropriate inducing substrate and an optimum medium composition. The importance of cellulase-free xylanase systems in the paper and pulp industry has initiated research into the correlation between the production of xylanases and cellulases by microorganisms. Filamentous fungi are particularly interesting producers of xylanases since they excrete the enzymes into the medium and their enzyme levels are much higher than those of yeast and bacteria. However, fungal xylanases are generally associated with cellulases. Selective production of xylanase is possible in the case of Trichoderma and Aspergillus species using only xylan as the carbon source. On cellulose these strains produce both cellulase and xylanase which may be due to traces of hemicellulose present in the cellulosic substrates. Cheaper hemi cellulosic substrates like corn cob, wheat bran, rice bran, rice straw, corn stalk and bagasse have also been found to be most suitable for the production of xylanases in the case of certain microorganisms such as Aspergillus, Penicillium and alkalophilic thermophilic Bacillus species.

Keywords: Xylanases, fungi, xylan, solid state fermentation.