Isolation and characterization of textile dye degrading native bacterial strains from textile effluent contaminated sites
S.Barathi, P.Indra Arulselvi
Synthetic dyes constitute the largest and most versatile class of synthetic dyes used in the textile, pharmaceutical, food and cosmetics industries and represent major components in wastewater from these industrial dying processes. Biological decolorization of azo dyes is an alternative and efficient tool for environmental management. Hence, in this study totally 40 bacterial isolates were screened from textile effluent contaminated soil samples. Out of 40 bacterial isolates, six potential bacterial strains were chosen based on their decolorization efficiency. Among the six bacterial strains, T11 strain was found to decolorize maximum number of dyes followed by T1, T4, T9, T7 and T10. The strain T11 decolorized reactive red 94%, reactive blue 95%, reactive grey 94% and reactive violet 100% after 120 h incubation at 300ppm concentration. Moreover, the selected bacterial strains were showed resistance to various heavy metals like Cr, Mn, Pb, Zn and Fe. The Phytotoxicity effect of degraded product was evaluated after 5 days of degradation. Phytotoxicity test revealed the nontoxic nature of the degraded metabolites. Based on the biochemical characterization and 16s rDNA gene sequencing analysis, the selected bacterial strain T11 was identified as Bacillus firmus.