title: Laccase/HBT and laccase-CBM/HBT treatment of softwood kraft pulp: impact on pulp bleachability and physical properties.
abstract: Pycnoporus cinnabarinus laccase and a chimeric laccase-CBM were applied in softwood kraft pulp biobleaching in the presence of 1-hydroxybenzotriazole (HBT). The presence of CBM could enhance the laccase biobleaching potential as a decrease in the enzymatic charge and chlorine dioxide consumption, as well as an increase in pulp brightness were observed. Laccase/HBT treatment could be improved by increasing oxygen pressure from 1 to 3bar and pulp consistency from 5% to 10%. Conversely, under the same conditions, no improvement of laccase-CBM/HBT treatment was observed, indicating a different behavior of both systems. However, laccase-CBM/HBT treatment led to a better preservation of pulp properties. This effect was probably due to fiber surface modifications involving the action of the CBM. Transmission electron microscopy examination of pulp fibers indicated a retention of laccase-CBM inside the pulp fibers due to CBM binding and an increased external microfibrillation of the fibers due to enzymatic treatments.
authors.affiliation: INRA, UMR 1163 BCF, 13288 Marseille, France. holy.ravalason@gmail.com
authors.forename: Holy
authors.initials: H
authors.lastname: Ravalason
authors.forename: Frédérique
authors.initials: F
authors.lastname: Bertaud
authors.forename: Isabelle
authors.initials: I
authors.lastname: Herpoël-Gimbert
authors.forename: Valérie
authors.initials: V
authors.lastname: Meyer
authors.forename: Katia
authors.initials: K
authors.lastname: Ruel
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Joseleau
authors.forename: Sacha
authors.initials: S
authors.lastname: Grisel
authors.forename: Caroline
authors.initials: C
authors.lastname: Olivé
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Sigoillot
authors.forename: Michel
authors.initials: M
authors.lastname: Petit-Conil
mesh_terms: D001234:Aspergillus niger / Q000201:enzymology; D001709:Biotechnology / Q000379:methods*; D043366:Cellulose 1,4-beta-Cellobiosidase / Q000378:metabolism*; D007218:Industrial Microbiology / Q000379:methods; D042845:Laccase / Q000378:metabolism*; D008031:Lignin / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D010209:Paper; D055494:Pycnoporus / Q000201:enzymology; D014230:Triazoles / Q000378:metabolism*
chemical_list: D014230:Triazoles; C076151:Kraft lignin; D008031:Lignin; C011852:1-hydroxybenzotriazole; D042845:Laccase; D043366:Cellulose 1,4-beta-Cellobiosidase