Treatment of Douglas‐Fir Heartwood Thermomechanical Pulp with Laccases: Effect of Treatment Conditions on Peroxide Bleaching

Abstract

Douglas-fir heartwood thermomechanical pulp was treated with laccase enzymes at 25 and 508C with and without added oxygen. The treated pulps were bleached with hydrogen peroxide at increasing alkali charges. Laccase treatments without added oxygen increased bleached brightness by 1.5 -2.5 pts ISO, and decreased hydrogen peroxide consumption by 15-20%. The enzyme treatments were not enhanced when supplemented with oxygen. When the effectiveness of four different laccase enzymes was compared for the treatment of Douglas-fir heartwood thermomechanical pulp, there were no significant differences found in the performance among the enzymes. Possible explanations for the observed results are given.

Fusarium concolorX4 Pretreatment Suppresses Light-Induced Yellowing of High-Yield Pulp

“…[16,17]. ese enzymes can degrade chromophores of pulp and its precursors, which are well beneficial to inhibit pulp yellowing [15,18,19]. Besides, the biotreatment could make pulps easier to be bleached and refined, thus decrease the consumption of bleaching agents and save considerable electrical energy, and the pulp strengths of burst, tear, and tensile were also improved [18].…”

Fungitoxic Potential of Extracts of Four Pinus spp. Bark to Inhibit Fungus Trametes versicolor (L. ex. Fr.) Pilát

“…On the other hand, bioactive fungi components that degrade wood have been studied as potential control agents for preserving wood (Teoh et al 2011), and the fungi´s ability to biodegrade xenobiotics soil contaminants has been investigated (Baldrian 2008). Enzymes generated by fungi can be used as wood biopulped agents (Villalba et al 2006), textile plant agents (Mohiuddin et al 2005), cellulosic pulp bio-bleaching agents (Chandra et al 2007), and also can be used on polymer synthesis, for antibiotics production and flavonoids functionalize (Mikolasch and Schauer 2009). Such enzymes have also been an object study on hydrolysis and oxidationreduction reaction mechanisms (Hamel et al 2002;Hofrichter 2002).…”