Bacterial Degradation of Synthetic Dye by Pseudomonas sp. Obtained from Dyeing Mill Effluent

Abstract

Environmental pollution is one of the major concerns of today’s world. Due to rapid industrialization and urbanization, a large number of wastes are generated and discharged into the environment and causing major pollution problems. For obtaining reactive dye decolorizing bacterial isolates, effluent samples were collected from a dyeing mill. From bacterial pure culture, 10 isolates were selected for screening. Screening of these isolates for the capability to decolorize and degrade reactive dye was performed in a nutrient broth medium containing reactive dye. 6 isolates among these bacterial isolates showed dye decolorizing ability within 120 hours of incubation. These isolates were further identified based on cultural, morphological, and biochemical characteristics. These characteristics indicated that these six bacterial isolates were distributed to the bacterial genus of Bacillus (2 isolates), Pseudomonas (2 isolates), Aeromonas (1 isolate), and Alcaligenes (1 isolate). For the study of dye decolorization and degradation, Reactive Dark Blue dye used in jute and textile industries was chosen. Pseudomonas, a prominent dye decolorizing isolate during screening, was taken for the optimization of different physicochemical parameters. This bacterium decolorized and grew well up to 500 mgL-1 of Reactive Blue dye. Pseudomonas sp. showed noteworthy decolorization of approximately 84% at 200 mgL-1 of dye concentration after 96 h of incubation. The optimum temperature for dye degradation was at 37 °C. The maximum level of decolorization for Pseudomonas sp. was observed at pH 8.0. This isolate showed better decolorization extent under static conditions rather than shaking conditions. This result indicated that the dye had been utilized by this bacterial isolate. It can be concluded that Pseudomonas is a prospective candidate in the biodegradation of Reactive Blue dye and might be useful in bioprocess technology used for the bioremediation of dyeing mill effluents.