Modern environmentally sound trends in manufacturing of bleached paper pulp involve development of totally chlorine free (TCF) bleaching and zero liquid effluent (ZLE)processes. Lipophilic extractives are among the most problematic wood constituents for both TCF and ZLE processes, since they tend to accumulate in circuits resulting in new manufacturing (“pitch” deposits) and environmental troubles. The extractive-degrading fungi Bjerkandera adusta, Phlebia radiata, Pleurotus pulmonarius and Poria subvermispora were assayed to remove these compounds from Eucalyptus globulus wood using solid-state fermentation conditions. The pretreated chips were subjected to laboratory kraft pulping to assess the effectiveness of the treatment. Evaluation of extractive removal was carried out by gas chromatography-mass spectrometry of extracts from the pretreated wood and the pulps and black liquors after cooking. As a result of the fungal pretreatment, up to 75% decreased levels of problematic compounds (including free and esterified sitosterol) were found in pulps and liquors. Moreover, a significant reduction of potential acute toxicity was found in black liquors from wood pretreated with three of the fungi. The biopulps were TCF-bleached, refined and handsheet properties evaluated to select the most advantageous fungi from the point of view of their industrial applicability in environmentally sound pulp manufacturing processes.

Instituto de Recursos Naturales y Agrobiología, CSIC, Reina Mercedes 10, P.O. Box 1052, E-41080 Seville, Spain, Centro de Investigaciones Biológicas, CSIC, Velázquez 144, E-28006 Madrid, Spain, ENCE, Centro de Investigación y Tecnología, Ctra. Campañó s/n, E-36157 Pontevedra, Spain, and Centre Technique du Papier, Domaine Universitaire, P.O. Box 251, Cedex 9, F-38044 Grenoble, France

This study has been partially supported by the European Union (contract FAIR-CT95-0560, “Wood extractives in pulp and paper manufacture: Technical and environmental implications and biological removal”) and by the Spanish Biotechnology Program.

Peer reviewed