Biological processing of pine logs for pulp and paper production with Phlebiopsis gigantea

Phlebiopsis gigantea (=Phanerochaete gigantea) is a white rot fungus that rapidly colonizes cut stumps, stems, and branches of pine. Two laboratory and several field studies showed that inoculation of red pine logs, Pinus resinosa, with P. gigantea reduced the pitch content of wood, facilitated bark removal, modified wood cells, and controlled detrimental sapstain. Isolations from inoculated logs revealed up to 100 and 80% colonization of the sapwood by P. gigantea after 8 weeks in the field and 32 days in the laboratory, respectively. Logs colonized by P. gigantea in both the laboratory and field showed a 9 to 71% reduction in pitch content, as well as a significant enhancement of bark removal. Examination with Simons' stain of refined wood fibers from inoculated logs revealed an increase in cell wall porosity. Blue stain fungi that cause dark discoloration of the sapwood were inhibited by inoculation with P. gigantea. These studies demonstrate that biological processing of logs with P. gigantea can result in substantial benefits to the pulp and papermaking process.