Isolation, characterization and phylogenetic analysis of dye decolorizing bacteria from textile sludge

Abstract

Textile industries use various dyes which have become one of the key sources of environment pollution. As a result, it is necessary to remove these undesirable dyes from the effluent that is released to the environment. This study was envisaged to obtain potential bacterium that can degrade the reactive dyes present in soil/sludge samples collected from the textile disposal sites. Samples were collected aseptically from Narsingdi, Bangladesh. On the basis of the degradation rate, three bacterial strains were isolated using salt media (SM) for two dyes named Setazol Blue BB and Black B. Isolated bacterial strains were identified as Bacillus sp. (SSR_S4_19, SSR_B-3_19), Pseudomonas sp. (SSR_S-5_19) by 16srRNA gene sequencing analysis. For the decolorization experiment, SM broth containing specific dyes (1%) were inoculated with each of the strains. All the three strains could decolorize the soil sample within 24h which was estimated using spectrophotometry. The decolorization rate for Setazol Blue BB was 87.7% and 86.5% in 24hr for the strains SSR_S-4_19 and SSR_S-5_19 respectively. On the other hand, for Black B it was 92.6% and 85.22% in 24hr for the strains SSR_B-3_19 and SSR_S-4_19 respectively. Since these strains have been efficient in decolorizing the dyes, in future it may be a promising strain for industrial use.