Industrial effluent containing textile dyes is regarded as a major environmental concern in the present world. Crystal Violet is one of the vital textile dyes of the triphenylmethane group; it is widely used in textile industry and known for its mutagenic and mitotic poisoning nature. Bioremediation, especially through bacteria, is becoming an emerging and important sector in effluent treatment. This study aimed to isolate and identify Crystal Violet degrading bacteria from industrial effluents with potential use in bioremediation. The decolorizing activity of the bacteria was measured using a photo electric colorimeter after aerobic incubation in different time intervals of the isolates. Environmental parameters such as pH, temperature, initial dye concentration and inoculum size were optimized using mineral salt medium containing different concentration of Crystal Violet dye. Complete decolorizing efficiency was observed in a mineral salt medium containing up to 150 mg/l of Crystal Violet dye by 10% (v/v) inoculums of Enterobacter sp. CV–S1 tested under 72 h of shaking incubation at temperature 35 °C and pH 6.5. Newly identified bacteria Enterobacter sp. CV–S1, confirmed by 16S ribosomal RNA sequencing, was found as a potential bioremediation biocatalyst in the aerobic degradation/de-colorization of Crystal Violet dye. The efficiency of degrading triphenylmethane dye by this isolate, minus the supply of extra carbon or nitrogen sources in the media, highlights the significance of larger-scale treatment of textile effluent.

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Water pollution from textile effluent is now one of the major issues all over the world. Malachite Green dye of the triphenylmethane group is a key component of textile effluents. This study aimed to isolate and identify potential Malachite Green dye degrading bacteria from textile effluents. Different growth and culture parameters such as temperature, pH, inoculum-size and dye concentration were optimized to perform the dye-degradation assay using different concentrations of Malachite Green dye in mineral salt medium. A photoelectric-colorimeter was used to measure the decolorizing activity of bacteria at different time intervals after aerobic incubation. Two competent bacterial strains of Enterobacter spp. (CV-S1 and CM-S1) were isolated from textile effluents showing potential degradation efficiency against Malachite Green dye. The RAPD analysis and 16S rRNA sequencing confirmed the genetical difference of the isolated strains Enterobacter sp. CV-S1 and Enterobacter sp. CM-S1. The two bacterial strains CV-S1 and CM-S1 showed complete Malachite Green dye degradation up to 15 mg/l under shaking condition with 5% (v/v) inoculums at pH 6.50 and temperature 35°C within 72 and 144 hours respectively. These findings indicate that the two potential bacterial strains can be used in large scale treatment of textile effluents in the future.