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Decolorization of Congo Red dye by bacterial isolates |
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PP: 41-48 |
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Author(s) |
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M. A. M. Abo-State,
Y. E. Saleh,
H. A. Hazaa,
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Abstract |
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| Congo Red (CR) is one of the azo dyes which is widely used in textile industries and has carcinogenic properties. Large amount of wastewater containing these dyes is discharged from the printing units causing an environmental pollution. So, it is very important to degrade these dyes before discharging it. Several bacterial strains isolated from textile wastewater were tested to study its potential to decolorize CR dye. The decolorization of Congo Red dye by the bacterial strains was observed in various concentrations (25 to 400 mg/L) of CR dye. The most potent bacterial strains were B. cereus MAM-B22, Ochrobactrum sp. MAM-C9, Achromobacter xylosoxidans MAM-29 and B. cereus MAM-B11. The maximum decolorization was observed by B. cereus MAM-B22 which removed 96.92%, 93.34%, 89.28%, 82.51%, 75.57%, 69.18% and 66.73% of 25, 50, 100, 150, 200, 300 and 400 mg/L respectively after 3 days of incubation at 37°C. When different pH values were used, the maximum decolorization was observed at pH 7.0 which was 90.21%, 90.03%, 89.62% and 85.84% by Ochrobacterum sp. MAM-C9, B. cereus MAM-B22, A. xylosoxidans MAM-29 and B. cereus MAM-B11 respectively. The effect of temperature was studied at a range of 25-60°C and the optimum temperature was 37°C. The percentage of decolorization of CR was 92.56%, 91.37%, 89.29% and 88.69% by B. cereus MAM-B22, Ochrobacterum sp. MAM-C9, A. xylosoxidans MAM-29 and B. cereus MAM-B11 respectively. The decolorization percentage was bacterial strain, concentration and time dependent. |
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