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Textile industry is the largely employed sector of synthetic dyes which creates various
environmental problems through their untreated or partially treated effluents. Most of those
synthetic textile dyes are highly recalcitrant to natural degradation processes. The general
approach o f the study was to determine bioremediation potential of native bacteria for textile
dye Cl Direct Blue 201. The effect of physiochemical parameters were optimized for five
bacterial isolates (Pseudomonas sp.l, Pseudomonas sp.2, Bacillus sp.l, Bacillus sp.2,
Micrococcus sp.) on decolorization of Cl Direct Blue 201. Decolorization potential was studied
by introducing overnight starved equalized bacteria suspensions into filter sterilized dye
solutions at different concentrations of dye, temperature and pH. 3 ml sample aliquots were
removed at 2 days interval for a period of 14 days and decolorization percentage was
determined by spectrophotometric analysis. After 14 days of incubation at 50 ppm
concentration, decolorization percentage by Pseudomonas sp.2, Pseudomonas sp.l, Bacillus
sp.l, Micrococcus sp., Bacillus sp.2 were recorded as 67.93±1.23% , 65.20±2.94%,
58.81±0.81%, 53.60±2.51%, 50.30±1.24% respectively. The decolorization of dye by each
bacterium was studied at 24°C, 28°C and 32°C temperatures respectively for 14 days of
incubation. The highest decolorization was detected when the samples were incubated at 32°C
than at the other two temperatures. At 14 days of incubation at pH 7.0, Pseudomonas sp. 1 and
Micrococcus sp. were showed the highest decolorization percentages as 55.91± 1.45% and
55.54±1.17% respectively. None o f bacteria isolates showed remarkable decolorization when
the medium was acidic pH. In-vitro photolysis experiment revealed that decolorization of Cl
Direct Blue 201 dye was not occurred by natural sunlight. Hence, optimized bacterial isolates
can be used as a green solution for textile dye pollution.
