title: Biobleaching of eucalypt kraft pulp with a two laccase-mediator stages sequence.
abstract: A new biobleaching sequence, with two enzymatic stages based on the application of laccase-mediator systems, was tested (L(1)EL(2)QPo) in order to increase the effectiveness of enzyme delignification on eucalypt kraft pulp. Different synthetic -1-hydroxybenzotriazole (HBT) and violuric acid (VA) - and natural - syringaldehyde (SyAl) - mediators were used in the laccase stages and the biobleached pulp were compared in terms of chemical, optical and physico-mechanical properties. The pulp bleached with HBT or VA showed similar delignification (64.1% and 65.9% respectively) and optical properties (86.4% and 86.1% ISO brightness respectively) than an industrial TCF pulp (68.3% delignification and 84.8% ISO brightness). SyAl improved these properties in a lower extent (56.71% delignification and 80.52% ISO brightness). Regarding physico-mechanical properties of pulp, the biobleaching sequence had no a negative effect, even some slight improvements were observed in very specific cases.
authors.affiliation: Department of Textile and Paper Engineering, Universitat Politècnica de Catalunya, Colom 11, E-08222 Terrassa, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Moldes
authors.forename: E M
authors.initials: EM
authors.lastname: Cadena
authors.forename: T
authors.initials: T
authors.lastname: Vidal
mesh_terms: D001673:Biodegradation, Environmental; D005052:Eucalyptus / Q000737:chemistry*; D042845:Laccase / Q000737:chemistry*; D010209:Paper; D012037:Refuse Disposal / Q000379:methods*
chemical_list: D042845:Laccase