Decolorization of methanil yellow G by a halophilic bacterial consortium

Abstract:

[Objective] In order to obtain highly efficient bacterial consortium that can rapidly decolorize azo dyes in high salinity environment. [Methods] A halophilic bacterial consortium was obtained by enrichment, and its community structure was determined by Illumina HiSeq2500 sequencing platform. The degradation characteristics were determined by spectrophotometry. The degradation mechanism was analyzed by GC-MS and Fourier Transform infrared spectroscopy. The toxicity of azo dye and degradation product were compared by micronuclear test. [Results] At 10% salinity, the bacterial consortium decolorizes methanil yellow G completely in 8 h. The bacterial consortium was composed of Zobellella, Rheinheimera, Exiguobacterium and Marinobacterium. At pH 6.0, with yeast powder as carbon sources, peptone or potassium nitrate as nitrogen sources and 1% NaCl were the optimal decolorization conditions. Decolorization metabolites of methanil yellow G were less toxic than original dye. The main degradation products of methanil yellow G were p-aminodiphenylamine and diphenylamine. In addition, the bacterial consortium also decolorized various azo dyes, such as acid magenta GR and direct lake blue 5B. [Conclusion] A halophilic bacterial consortium for fast degradation of azo dyes was obtained, with the application potential to treat high-salt printing and dyeing wastewater.