Biobleaching of Eucalyptus globulus kraft pulps: Comparison between pulps obtained from exploded and non-exploded chips

The aim of this work was to evaluate the response to biobleaching of steam exploded kraft pulps and to compare the results with the controls. For this end, a laccase-mediator treatment using commercial laccase (Novozyme 51003) and a natural mediator (acetosyringone) were assayed, followed by alkaline extraction and hydrogen peroxide stages. Our approach resulted in exploded biobleached pulps with lower kappa number and improved optical properties compared to controls, even after subjecting pulps to accelerated ageing. Additionally, use of hydrogen peroxide was reduced. The LMS (laccase-mediator system) had a smaller impact on the properties of the bleached pulps and on hydrogen peroxide consumption than the steam explosion process did. (C) 2010 Elsevier Ltd. All rights reserved.