Bocchini, Daniela A. [UNESP]Damiano, Valquiria B. [UNESP]Gomes, Eleni [UNESP]Da Silva, Roberto [UNESP]2014-05-272014-05-272003-03-01Applied Biochemistry and Biotechnology - Part A Enzyme Engineering and Biotechnology, v. 106, n. 1-3, p. 393-402, 2003.0273-2289http://hdl.handle.net/11449/67208The alkalophilic Bacillus circulans D1 was isolated from decayed wood. It produced high levels of extracellular cellulase-free xylanase. The enzyme was thermally stable up to 60°C, with an optimal hydrolysis temperature of 70°C. It was stable over a wide pH range (5.5-10.5), with an optimum pH at 5.5 and 80% of its activity at pH 9.0. This cellulase-free xylanase preparation was used to biobleach kraft pulp. Enzymatic treatment of kraft pulp decreased chlorine dioxide use by 23 and 37% to obtain the same kappa number (κ number) and brightness, respectively. Separation on Sephadex G-50 isolated three fractions with xylanase activity with distinct molecular weights.393-402engBacillus circulansBiobleachingKraft pulpThermophilicXylanasecellulasechlorine dioxideenzymesephadexxylan endo 1,3 beta xylosidasebleachingbrightnessconference paperenzyme activityenzyme isolationenzyme stabilityEucalyptusextracellular spacehydrolysisisolation proceduremolecular weightnonhumanpHpulp processingseparation techniquetemperaturethermostabilitywoodBacillusBiotechnologyCellulaseEndo-1,4-beta XylanasesEnzyme StabilityHydrogen-Ion ConcentrationHydrolysisKineticsThermodynamicsXylansXylosidasesTrabalho apresentado em evento10.1385/ABAB:106:1-3:393WOS:000182725000036Acesso aberto2-s2.0-003807173070912417428519209424175688206545