REDUCTION OF RESIN CONTENT IN WOOD CHIPS DURING EXPERIMENTAL BIOLOGICAL PULPING PROCESSES

This research examined the ability of two biopulping fungi, Ceriporiop sis subvermispora and Phanerochaete chrysosporium, to lower the resin content of wood chips, and the ability of a commercial depitching fung us, Ophiostoma piliferum, to biopulp. Biopulping is defined as the pre treatment of wood chips with lignin-degrading fungi for mechanical pul ping. The study also examined the effect on sulfite pulping of the fun gal pretreatments. Ceriporiopsis and Ophiostoma lowered the resin cont ent of loblolly pine (2.55-2.64%) by 18-27% in 2 weeks and 33-35% in 4 weeks (Phanerochaete was not studied), and all three fungi lowered th e resin content of spruce wood from 1.2% to 0.8-0.9% in 2 weeks. In a biopulping study, pretreatment of pine wood chips for 4 weeks with Cer iporiopsis lowered the refining energy requirement by 30%, improved ce rtain strength properties, and lowered brightness and light scattering coefficient, in comparison to sterile control chips. By contrast, Oph iostoma had no effect on energy requirements, or on strength and optic al properties. Pretreatment of spruce chips with the two biopulping fu ngi, but not with Ophiostoma, led to lower kappa numbers on sulfite co oking. Tensile index of paper from the sulfite-pulped chips was increa sed slightly by Ophiostoma and unchanged by the biopulping fungi. Tear index was increased slightly by Ceriporiopsis, decreased slightly by Phanerochaete, and not changed by Ophiostoma.