Enhanced azo dye biodegradation at high salinity by a halophilic bacterial consortium

Abstract

The aim of this work was to study the bioaugmentation of hydrolysis acidification (HA) by a halophilic bacterial consortium. A bacterial consortium was enriched at 5% salinity, and it decolorized metanil yellow G (MYG) at salinities of 1%-15% and dye concentrations of 100-400 mg/L under static conditions. A HA system was constructed to assess the effectiveness of bioaugmentation by the halophilic bacterial consortium. The HA system showed obviously better performance for decolorization and COD_Mn removal and presented higher the 5-day biological oxygen demand (BOD₅)/COD_Mn (B/C) ratio after bioaugmentation. MiSeq sequencing results indicated that the bacterial communities remarkably shifted and that the bacterial diversity was increased after bioaugmentation. Marinobacterium invaded the native microbe community and became the dominant bacterial genus in the bioaugmented HA, and it played a key role in azo dye decolorization. Therefore, bioaugmentation with a halophilic bacterial consortium improved the HA system for decolorization of azo compounds.

Keywords: Azo dye; Decolorization; Halophilic bacterial consortium; Microbial community; Salinity.