par Luhahi-Lumba, F.;Penninckx, Michel
Référence Applied microbiology and biotechnology, 36, 6, page (733-738)
Publication Publié, 1992
Article révisé par les pairs
Résumé : Streptomyces sp. strain EC10 degraded efficiently the hemicellulose fraction of wheat straw. Three forms of β-xylanases detected in the culture filtrate were purified by precipipation with ammonium sulphate, chromatography on DEAE-Sephadex A-50 and gel filtration on Sephadex G-100. The three purified enzymes (Xia, Xib and X′ii) were homogeneous by polyacrylamide gel electrophoresis. The enzymes were typical non-debranching endo-β-xylanases (1,4-β-d-xyla xylanohydrolases; E.C. with respective relative molecular weights of 32,000, 22,000 and 21,000 and isoelectric points of 6.8, 8.9 and 5.2. The enzymes were highly specific for xylans and showed optimal activity at pH 7.0-8.0 and 60°C. The preparations were completely free from cellulolytic activity (endoglucanase) and showed high thermal stability. No synergy between the three enzymes was detected for complete xylan hydrolysis of deacetylated arabino- and glucuronoxylans.