Globally, water pollution from the textile industries is an alarming issue. Malachite Green dye of the triphenylmethane group is an extensively used dye in the fabric industries that is emitted through textile wastewater. This study aimed to isolate and characterize potential Malachite Green (MG) dye degrading bacteria from textile effluents. Different growth and culture parameters such as temperature, pH and dye concentration were optimized to perform the dye-degradation assay using different concentrations of MG dye in the mineral salt medium. A photo-electric-colorimeter was used to measure the decolorizing activity of bacteria at different time intervals after aerobic incubation. Two potential bacterial strains of Enterobacter spp. CV-S1 (accession no: MH450229) and Enterobacter spp. CM-S1 (accession no: MH447289) were isolated from textile effluents exhibiting potential MG dye decoloring efficiency. Further, the RAPD analysis and 16S rRNA sequencing confirmed the genetic differences of the isolated strains. Enterobacter sp CV-S1 and Enterobacter sp CM-S1 can completely decolor MG dye up to 15 mg/L under shaking condition without any requirement of sole carbon source. Thus, these two bacteria have the potency to be utilized in the textile wastewater treatment plant.
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.