Isolation and identification of dye degrading bacteria from textile sludge to eradicate environmental hazards and maintain a sustainable environment

Abstract

Bangladesh's textile industries contribute to the country's enormous wealth and prosperity, but they are also silently destroying the country's water bodies and surrounding areas. Textile dye wastewater is brightly colored and contains a wide range of chemicals, toxins, and heavy metals. Under the Bangladesh Environment Conservation Act, 1995, and the Environment Conservation Rules, 1997, the government designated textile dyeing industries as "red industries" (the most polluting) and made Effluent Treatment Plants (ETPs) mandatory for the factories. However, the majority of them lack ETP because chemical and physical methods require constant monitoring and are extremely costly to operate. Industry is budding, and so is pollution. Microbial bioremediation offers an easy and affordable solution to this problem and helps to maintain a sustainable environment. Keeping the above situation in mind, research on isolating a dye degrading bacterium is preferred. In this study, one decolorizing bacterial isolate has been isolated from industrial textile sludge with the ability to decolorize 1% of commercially available Reactive Violet 5R (RV5R) dye. About 91.16% of RV5R dye was decolorized after 48 hours of incubation at 370C and 80 rpm. The absorbance was measured at 510 nm for the supernatant with the help of a spectrophotometer. The whole cell culture and the supernatant of the culture as an inoculate showed the same result. The study was also conducted under aerobic conditions without using any co-substrate and using the Reactive Violet 5R (RV5R) dye as the only carbon and energy source for the bacterial isolate. The cultural, morphological, and physiological characteristics of that bacteria isolate have been detected. Through analyzation with ABIS Microbiology software, the isolate is identified as either Actinobacillus rossi (85.9% similarity) or Acromonas salmonicida subsp. smithia (82.2% similarity). For further molecular identification, the DNA was extracted, and PCR amplification of the 16S rRNA gene was conducted. The gel electrophoresis was performed to check whether the band was present or not. The future goal is to identify the bacterium isolate at the genomic level and identify the gene or genes that synthesize enzymes capable of decolorizing textile dyes. If everything goes as planned, this bacterium will undoubtedly contribute to the creation of a sustainable environment for our country.