A white-rot fungus Antrodiella sp. RK1 was evaluated for its use in bi
omechanical pulping process. After 4 weeks of pretreatment of aspen wo
od chips, electrical energy needed for fiberizing chips during mechani
cal pulping was reduced by about 26%. The burst, tear, tensile indices
and fiber length were improved, whereas brightness, density and light
scattering coefficient were reduced. Scanning electron micrographs sh
owed that the fungus grew well, both on the chip surface as well as in
its interiors. Localized thinning and fragmentation of the wood cell
walls were clearly visible. Calcium crystals were found in association
with hyphae in the eroded areas. Laccase was found to be the dominant
enzyme in the extracts of the culture grown on mechanical pulp of asp
en wood.