Journal of Biological Sciences

Year: 2004 | Volume: 4 | Issue: 1 | Page No.: 27-33
DOI: 10.3923/jbs.2004.27.33

Isolation and Some Properties of New Xylanase from the Intestine of a Herbivorous Insect (Samia Cynthia Pryeri)

Narayan Roy, Md. Masud Rana and A.T.M. Salah Uddin

Abstract: Xylan the major portion of the hemicellulose of plant cell walls are heterogeneous polysaccharides. Xylanases are enzymes obtained from different species of microorganisms that degrade the xylosidic linkages of xylans backbone producing xylose with other monoresidues. In this study, xylanase producing strains were isolated from intestine of a herbivorous insect at Rajshahi University Campus. The strains were isolated on xylan agar media and screened by &946; -xylanolysis method. Zymogram analysis was confirmed the xylanolytic activity. The strains was identified to be Aeromonas sp. and xylanase enzyme was detected in the culture supernatant of the strain. Xylanase enzyme was purified from culture supernatant of Aeromonas sp. by ammonium sulfate precipitation, gel filtration on Sephadex G-100 followed by ion exchange chromotography on DEAE-cellulose. In DEAE cellulose column chromatography, three protein peaks F-1a, F-1b and F-1c were appeared. Among these peaks, only F-1b showed xylanase activity and the degree of purification attained 64.54 fold. The purified enzyme gave single band on SDS-polyacrylamide gel electrophoresis indicating its homogeneity. The enzyme gave maximum activity against xylan as substrate at pH 7.0 and temperature at 55 ° C. The Km value of xylanase was found to be 0.91% using the oat spelt xylan as substrate. The xylanase hydrolyzed strongly oat spelt xylan and birch wood xylan but didnot hydrolyze cellulose, carboxymethyl cellulose and starch. Xylose was detected as the hydrolysis products of oat spelt xylan by the xylanase.

Keywords: aeromonas sp, xylanase, zyumogram and km

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