1. Swedish University of Agricultural Sciences, Department of Forest Products, S—750 07 Uppsala, Sweden
2. Current address until Nov. 20th, 1997: Department of Mycology, Institute of Biochemical Technology & Microbiology, University of Technology Vienna, Getreidemarkt 9/172, A—1060 Vienna, Austria
3. Swedish Pulp and Paper Research Institute, STF1, Box 5604, S—11486 Stockholm, Sweden