Bacillus amyloliquefaciens AD 20 and Bacillus altitudinis AD 14 Isolated from a Dye Pond Decolorize Synthetic Textile Reactive Dyes

A screen of textile effluents, receiving waterbodies, and waste sites near a textile factory was undertaken to isolate new bacteria strains capable of dye degradation. Out of the 45 isolates, two dye decolorizers, Bacillus altitudinis AD14 and B. amyloliquefaciens AD20, obtained from the sediment samples were identified by cultivation and 16S rRNA gene sequencing. Decolorization testing was performed under static aerobic conditions in the laboratory. The two Bacillus species showed dye decolorization capabilities on media containing each of these four commercial textile azo dyes- Reactive Blue 4 Red (RBFR), Cibacron Brilliant Orange 4 Red (COFR), Cibacron Brilliant Yellow 6 Percent Green (CYPGS), and Turquoise Cibacron Green (TCG). At the end of a ten-day incubation period, B. amyloliquefaciens AD20 was more efficient in dye reduction than B. altitudinis AD14 on CYPGS and COFR at a magnitude of four-fold and two-fold, respectively, while B. altitudinis AD14 only outperformed it in the TCG dye media. The isolates performed best on medium containing RBFR; the principal dye used by the textile factory. Genome annotation revealed the absence of plasmids and the presence of putative genes associated with dye decolorization, such as laccase and azoreductases