EVALUATING ISOLATES OF PHANEROCHAETE-CHRYSOSPORIUM AND CERIPORIOPSIS-SUBVERMISPORA FOR USE IN BIOLOGICAL PULPING PROCESSES

Decay of birch (Betula papyrifera), aspen (Populus tremuloides) and loblolly pine (Pinus taeda) wood by 19 isolates of Phanerochaete chrysosporium showed considerable variation in percent weight loss and loss of lignin and wood sugars. Birch and aspen woods were degraded to a greater extent than loblolly pine wood. Among the isolates tested, a great deal of variation was observed in their ability to preferentially degrade lignin. Isolate BKM-F-1767 resulted in the greatest loss of lignin on the deciduous woods tested. Many isolates of P. chrysosporium removed all cell wall components causing a nonselective type of white rot. In contrast, nine isolates of Ceriporiopsis subvermispora caused moderate weight losses and preferential degradation of lignin in aspen, birch and loblolly pine wood. Less variation among isolates was observed in the cell wall components removed from all woods tested. Lignin losses ranged from 19 to 38% in loblolly pine and 50-80% in aspen and birch wood. Polyacrylamide gel electrophoresis (SDS-PAGE) showed a wide variety of band patterns for extracellular enzymes among isolates of P chrysosporium, but relatively uniform protein bands among isolates of C. subvermispora. Only a few isolates of P chrysosporium appear to be strains that preferentially remove large amounts of lignin from wood, whereas all isolates of C. subvermispora tested are selective lignin degraders on deciduous as well as coniferous wood.