title: Production in Trichoderma reesei of three xylanases from Chaetomium thermophilum: a recombinant thermoxylanase for biobleaching of kraft pulp.
abstract: Three endoxylanase genes were cloned from the thermophilic fungus Chaetomium thermophilum CBS 730.95. All genes contained the typical consensus sequence of family 11 glycoside hydrolases. Genomic copies of Ct xyn11A, Ct xyn11B, and Ct xyn11C were expressed in the filamentous fungus T. reesei under the control of the strong T. reesei cel7A (cellobiohydrolase 1, cbh1) promoter. The molecular masses of the Ct Xyn11A, Ct Xyn11B, and Ct Xyn11C proteins on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) were 27, 23, and 22 kDa, respectively. Ct Xyn11A was produced almost as efficiently as the homologous xylanase II from a corresponding single-copy transformant strain. Ct Xyn11B production level was approximately half of that of Ct Xyn11A. The amount of Ct Xyn11C was remarkably lower. Ct Xyn11A had the highest temperature optimum and stability of the recombinant xylanases and the highest activity at acid-neutral pH (pH 5-7). It was the most suitable for industrial bleaching of kraft pulp at high temperature.
authors.affiliation: Roal Oy, 05201, Rajamäki, Finland. arja.mantyla@borenius.fi
authors.forename: Arja
authors.initials: A
authors.lastname: Mäntylä
authors.forename: Marja
authors.initials: M
authors.lastname: Paloheimo
authors.forename: Satu
authors.initials: S
authors.lastname: Hakola
authors.forename: Emilia
authors.initials: E
authors.lastname: Lindberg
authors.forename: Sanna
authors.initials: S
authors.lastname: Leskinen
authors.forename: Jarno
authors.initials: J
authors.lastname: Kallio
authors.forename: Jari
authors.initials: J
authors.lastname: Vehmaanperä
authors.forename: Raija
authors.initials: R
authors.lastname: Lantto
authors.forename: Pirkko
authors.initials: P
authors.lastname: Suominen
mesh_terms: D000143:Acids; D001709:Biotechnology / Q000379:methods; D002597:Chaetomium / Q000201:enzymology* / Q000235:genetics; D043364:Endo-1,4-beta Xylanases / Q000235:genetics* / Q000378:metabolism*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology / Q000379:methods; D007220:Industrial Waste; D010209:Paper; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000378:metabolism*; D014242:Trichoderma / Q000201:enzymology / Q000235:genetics*
chemical_list: D000143:Acids; D007220:Industrial Waste; D011993:Recombinant Fusion Proteins; D043364:Endo-1,4-beta Xylanases