Biodegradation of textile dye by indigenously isolated bacteria BACILLUS and PSEUDOMONAS Sp. and their discard after bio-treatment

Abstract

Indigenous bacterial isolates of Bacillus and Pseudomonas sp. were used to biodegrade the textile dye (light green) in the laboratory. The 50, 100 and 150 ppm of textile dye light green were completely decolorized after 24 h, while 200 ppm after 30 h of incubation. Both the isolates decolorized 76 to 79 % of dye after 24 h at pH 7 to 7.5 and temperature 37 °C. The crude enzyme extract of these isolates was also employed for decolorization of textile dye. Crude enzyme extract 0.5, 1 and 1.5 mL of Bacillus sp. showed 10, 45 and 74 % of decolorization, while 2 and 2.5 mL showed 100 % decolorization. Bacterial elimination was also done by inducing acetic acid stress. The results indicated that both the indigenous bacteria showed colony forming ability (CFA) after 36 h only when the concentration of acetic acid was 20 mM and further higher concentration did not favored colony forming ability. Even the incubation of 60 mM of acetic acid for 24 h was not favorable for colony forming ability which indicates the elimination of bacteria due to acetic acid stress. The relative sensitivity of Sorghum vulgare Pers. CV SSG5000 towards the textile dye and its biodegraded products were studied. Thus, phytotoxicity studies revealed that the biodegradation of the textile dye by the Bacillus and Pseudomonas sp. led to detoxification of the textile dye light green. In conclusion, the use of indigenous bacterial isolates had great potential for the biodegradation of textile dyes.