Azo dyes are often known to be carcinogenic mutagenic and recalcitrant. Dyeing effluents have emerged as a significant cause of water contamination. Dyes influence all living forms, included humans, due to their xenobiotic characteristics and toxicity, as a result, hazardous dyes from coloured wastewater must be treated and removed before they are released into the ecosystem. Bioremediation is an innovative, cost-effective, and eco-friendly achievement of biotechnological novelty. Thirty dye-decolorizing indigenous strains were isolated from industrial wastewater in the present investigation from the Kashipur paper industry and SIDCUL industrial area Haridwar using NB medium amended with 100mg/l methyl red. Isolation of methyl red decolorizing bacteria was done by the serial dilution method followed by the spread plate method. A total of 30 isolates were isolated and subjected to primary screening which was done through the tube method. Following a primary screening of 30 isolates, ten potent strains were retained for further evaluation of the efficacy of color removal, designated as MRD2, MRD3, MRD4, MRD15, MRD17, MRD18, MRD19, MRD20, MRD22, and MRD28, which were presumably grouped into 10 genera according to morphology and biochemical assay. The bacterial strain MRD17 outperformed other tested strains via a decolorization assay with 74.28% degradation and decolorization of methyl red in 72 h, which was further identified as Entrobacter asburiae strain JCM6051 by 16S rRNA sequencing and submitted to the NCBI GenBank with accession number MT539179. In addition, the thermodynamic stability of the strain's 16S rRNA sequence was investigated using bioinformatics tools such as mfold and NEB cutter. These findings suggest that bacterial isolates might be useful in the development of an alternative and environmentally acceptable approach for decolorizing and degrading azo dyes from industrial waste.
Key words: Bioremediation, Decolorization, recalcitrant, Entrobacter asburiae, methyl red.
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