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Metabolites characterisation of laccase mediated Reactive Black 5 biodegradation by fast growing ascomycete fungus Trichoderma atroviride F03

2015; Elsevier BV; Volume: 104; Linguagem: Inglês

10.1016/j.ibiod.2015.05.019

1879-0208

Liyana Amalina Adnan, Palanivel Sathishkumar, Abdull Rahim Mohd Yusoff, Tony Hadibarata,

Biochemical and biochemical processes

In this study, fast growing ascomycete fungus Trichoderma atroviride F03 was explored to biodegrade bis-azo dye, Reactive Black 5 (RB5). The maximum RB5 biodegradation (91.1%) was achieved in the culture medium supplemented with an appropriate carbon source (glucose, 20 g l−1), and nitrogen source (yeast extract, 20 g l−1) at pH 5 and 27 °C. The laccase produced by T. atroviride F03 was involved in the RB5 biodegradation processes. The metabolites such as (I) 1,2,4-trimethylbenzene, (II) 2,4-ditertbutylphenol, and (III) benzoic acid-TMS) were identified as the biodegradation products of RB5 using gas chromatography-mass spectrometry (GC–MS). The presence of these metabolites suggested that RB5 biodegradation was initiated by the cleavage of azo bond forming naphthalene-1,2,8-triol and sulphuric acid mono-[2-(toluene-4-sulfonyl)-ethyl] ester. The sulphuric acid mono-[2-(toluene-4-sulfonyl)-ethyl] ester was further desulphonated to 1,2,4-trimethylbenzene. Then, the oxygenated ring of C1 and C2 naphthalene-1,2,8-triol was cleaved to 2-(2-carboxy-ethyl)-6-hydroxy-benzoic acid. The degradation of 2-(2-carboxy-ethyl)-6-hydroxy-benzoic acid could be proceeded with two pathways: (i) decarboxylation and methylation to form 2,4-ditertbutylphenol and (ii) decarboxylation mechanism that induced the formation of benzoic acid-TMS. Finally, this study proved that T. atroviride F03 might be a good candidate in treating textile effluent containing azo dye as this treatment does not generating aromatic amines.