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Biopulping of Eucalyptus grandis wood chips with Phanerochaete chrysosporium RP-78 was evaluated under non-aseptic conditions in laboratory and mill wood-yard. The ability of P. chrysosporium to compete with indigenous fungi present in fresh wood chips was notorious under controlled laboratory experiments. A subsequent step involved an industrial test performed with 10-ton of fresh wood chips inoculated and maintained at 37"38C for 39 days in a biopulping pilot plant. Biotreated wood chips were pulped in a chemithermomechanical pulping mill. Net energy consumption during refining was 745 kWh ton -1 and 610 kWh ton -1 of processed pulp for control and biotreated wood chips, respectively. Accordingly, 18.5% net energy saving could be achieved. Biopulps contained lower shive content and had improved strength properties compared to control pulps. Tensile index improved from 25"1 N m g -1 to 33.6"0.5 N m g -1 and delamination strength from 217"19 kPa to 295"30 kPa.

In the present study, it was evaluated how two different culture conditions for the biotreatment ofEucalyptus grandisbyCeriporiopsis subvermisporaaffect a subsequent high-yield kraft pulping process. Under the varied culture conditions investigated, different extracellular enzyme activities were observed. Manganese-peroxidase (MnP) secretion was 3.7 times higher in cultures supplemented with glucose plus corn-steep liquor (glucose/CSL) as compared to non-supplemented (NS) cultures. The biotreated samples underwent diverse levels of wood component degradation as losses of weight and lignin were increased in glucose/CSL cultures. Mass balances for lignin removal during kraft pulping showed that delignification was facilitated when both biotreated wood samples were cooked. Delignification efficiency did not correlate positively with MnP levels in the cultures. On the other hand, biopulps from NS and glucose/CSL cultures saved 27% and 38% beating time to achieve 28° Schopper-Riegler freeness during refining, respectively. Biopulps disposed of decreased tensile and tear resistances, thus easier refining of the biokraft pulps seems to be a consequence of less resistant fiber walls. Improved beatability of biopulps was tentatively related to short fibers and fines formation during refining. We suggest that to some extent polysaccharide depolymerization occurred during the biotreatment, which also resulted in diminished pulp yields in the case of glucose/CSL cultures.