Strains suitable for pulp and paper mill waste water treatment were screened from more than 10 white-rot fungi from nature by culture continuously in a series waste water-contained mediums in which amount of waste water increased gradually. Several strains were obtained which were waste water toxicity-resistance and could decrease COD (chemical oxygen demand) content of waste water effectively. In which, three strains, i. e. fungus Z-1, fungus Z-2 and fungus Z-3, were selected for treating medium-stage ...