Selection of Pleurotus pulmonarius from domestic basidiomycetous fungi for biodegradation of chlorinated dioxins as environmentally persistent organopollutants
2007
Yamaguchi, M.(Forestry and Forest Products Research Inst., Tsukuba, Ibaraki (Japan)) | Kamei, I. | Nakamura, M. | Takano, M. | Sekiya, A.
Screening of 174 strains of 20 native Japanese white-rot basidiomycetous fungi was carried out based on the decolorization rate of Remazol brilliant blue R, a persistent aromatic dye compound. A strain of Pleurotus pulmonarius was chosen on the basis of its decolorization rate. Since P. pulmonarius is cultivated in a scale of domestic outputs 250 tons in 2005 as an edible mushroom, the mushroom bed wastes appear to have the possibility of practical application of biologically treating dioxins on farmland in Japan. It was ascertained that the mycelium of P. pulmonarius spreads easily from the industrial culture bed wastes into unsterilized soils. Therefore, we assayed the fungal degradability of the following chlorinated dibenzo-p-dioxins: 2-monochloro-; 2,7-dichloro-; 1,2,4-trichloro-; 2,3,7,8-tetrachloro-; 1,2,3,7,8-pentachloro-; 1,2,3,4,7,8-hexachloro-; 1,2,3,4,6,7,8-heptachloro-; and octachloro-dibenzo-p-dioxins. Pleurotus pulmonarius degraded mono-, di-, and trichloro-dibenzo-p-dioxins to some extent (25%) and tetra-, penta-, hexa-, and hepta-dibenzo-p-dioxins to moderate extent (10%), whereas octachloro-dibenzo-p-dioxin was not degraded at all. The fungal metabolism of 2-monochloro-dibenzo-p-dioxin appeared to be initiated by biotransformation to hydroxylated monochloro-dibenzo-p-dioxin. These results suggest that the degradation of polychlorinated dibenzo-p-dioxins by P. pulmonarius is influenced by the chlorination pattern of the dibenzo-p-dioxins.
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