title: Can the laccase mediator system affect the chemical and refining properties of the eucalyptus pulp?
abstract: Application of a laccase mediator system (an L stage) to TCF and ECF bleached pulp from Eucalyptus globulus with low residual lignin content (KN(lig)1.0) provides useful information about its effects on hexenuronic acids, functional groups (carboxyl and carbonyl) and electrokinetic properties such as zeta potential and surface charge. The use of laccase from Trametes villosa in combination with the mediator 1-hydroxybenzotriazole (HBT) was found to oxidize cellulose to carbonyl groups and reduce the amount of carboxyl groups present in TCF pulp by effect of its partially removing hexenuronic acids from it. This result may open up new prospects for improving brightness stability in pulp. In addition, the laccase mediator system modifies the surface charge and zeta potential in the fibre suspension for the removal of ionizables groups in TCF pulp. This result has no adverse effect on the pulp refining efficiency. L treatment requires less mechanical energy than conventionally refined pulp to obtain an optimal tensile and tear index in handsheets. This behavior may be attributable to the modification of the electrokinetic properties.
authors.affiliation: Textile and Paper Engineering Department, ETSEIAT, Universitat Politècnica de Catalunya, Colom 11, E-08222 Terrassa, Spain.
authors.forename: Edith M
authors.initials: EM
authors.lastname: Cadena
authors.forename: Teresa
authors.initials: T
authors.lastname: Vidal
authors.forename: Antonio L
authors.initials: AL
authors.lastname: Torres
mesh_terms: D050260:Carbohydrate Metabolism; D002482:Cellulose / Q000378:metabolism; D005052:Eucalyptus / Q000737:chemistry* / Q000378:metabolism*; D006603:Hexuronic Acids / Q000032:analysis; D007700:Kinetics; D042845:Laccase / Q000378:metabolism*; D010084:Oxidation-Reduction; D010209:Paper; D013718:Tensile Strength; D014783:Viscosity
chemical_list: D006603:Hexuronic Acids; C095263:hexenuronic acid; D002482:Cellulose; D042845:Laccase