The ability of brown-rot fungus Daedalea dickinsii to decolorize and transform methylene blue dye

Abstract: The ability of Daedalea dickinsii to decolorize and transform methylene blue (MB) dye was investigated. MB was decolorized in potato dextrose agar medium after adding MB at concentrations of 50, 75, and 100 mg L⁻¹. D. dickinsii decolorized MB with decolorization index values of 0.92, 0.90, and 0.88 at MB concentrations of 50, 75, and 100 mg L⁻¹, respectively. The 100 mg L¹ MB concentration was selected for biotransformation in liquid potato dextrose broth medium. D. dickinsii transformed approximately 54% of the MB after a 14-day incubation. 3-(Dimethylamino)-7-(methylamino) phenothiazine (C₁₅H₁₆N₃S), 3,7-bis(dimethylamino)-4aH-phenothiazin-5-one (C₁₆H₁₉N₃SO), and 4-(dimethylamino)-2-[m(dimethylamino) phenylsulfinyl] benzenamine (C₁₆H₂₁N₃SO) were detected as MB metabolic products. This is the first report of MB transformation by the brown-rot fungi D. dickinsii. These results indicate that D. dickinsii can be used to decolorize and biotransform MB dye. Graphical Abstract: [Figure not available: see fulltext.]