Decolourisation and Degradation of Methylene Blue Dye by Brown-rot Fungus Gloeophyllum trabeum

The methylene blue (MB) dye is a compound that is widely applied for textile dyes, which has a negative effect on the environment. MB can cause several effects such as irritation of the skin if touched, gastrointestinal irritation if swallowed and cyanosis if inhaled. Due to the negative effects of MB, the residue of MB in the environment must be removed. One of the effective methods are bioremediation using microorganisms. In this study, the ability of brown-rot fungus Gloeophyllum trabeum to decolourise and degrade MB was investigated. G. trabeum cultures were added to potato dextrose agar (PDA) medium which contains MB at concentrations of 50, 75, and 100 mg L−1. The result shows that MB was decolourised by G. trabeum in PDA medium with decolourisation index (DI) of 0.874, 0.879, and 0.878 at MB concentrations of 50, 75, and 100 mg L−1, respectively. G. trabeum degraded MB approximately 47, 62 and 76% of 100 mg L−1 after incubated for 0, 7, and 14 days, respectively. Five metabolites were identified by LC-TOF/MS analysis. Based on data from m/z and references, the metabolite products were 2-nitro-5-(N,N-dimethyl)amino-benzene sulfonate (C8H10N2SO5), 2,5-diaminobenzene sulfonic acid (C6H8N2SO3), 4-(dimethylamino)-2-[m-(dimethylamino) phenylsulfinyl] benzenamine (C16H20N3SO), 2-amino-benzenesulfonic acid (C6H7NSO3), and thionine (C12H10N3S). This study indicated that G. trabeum can be used to decolourise and degrade MB dye.