Increased temperature, salinity and alkalinity restrict the biodecolorization rate of textile wastewater. In the present study, the halophilic alkalithermophilic bacterial consortium ZSY, which can decolorize azo dyes under 10% salinity, pH 10 and 50 °C, was enriched. It can decolorize Metanil Yellow G (MYG) under a wide range of pH values (8-10), temperatures (40-50 °C), dye concentrations (100-400 mg/L) and salinity levels (1%-10%). Laccase (Lac), lignin peroxidase (Lip), nicotinamide adenine dinucleotide-dichlorophenol indophenol reductase (NADH-DCIP) and azoreductase are involved in the decolorization process. A decolorization pathway of MYG was proposed via gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FTIR). The toxicity of MYG decreased after decolorization by ZSY consortium. A metagenomic sequencing approach was subsequently applied to identify the functional genes involved in decolorization. Overall, this halophilic alkalithermophilic bacterial consortium could be a promising candidate for the treatment of textile wastewater in environments with increased temperature, salinity and alkalinity.
Keywords: Alkalithermophilic; Azo dye; Decolorization; Halophilic bacteria.
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