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The Scientific World Journal
Volume 2012, Article ID 512454, 9 pages
Research Article

Removal of Triphenylmethane Dyes by Bacterial Consortium

1Laboratory of Analysis, Treatment, Valorisation and Environmental Pollution and Products “LR01ES16”, Faculty of Pharmacy, University of Monastir, Monastir Avicenne Street, Monastir 5000, Tunisia
2Groupe de Recherche en Ecologie Buccale, Faculté de Médecine Dentaire, Université Laval 2420 rue de la Terrasse, QC, Canada G1V 0A6

Received 30 December 2011; Accepted 16 January 2012

Academic Editors: F. Kawai, A. Scozzafava, and D. Zhou

Copyright © 2012 Jihane Cheriaa et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A new consortium of four bacterial isolates (Agrobacterium radiobacter; Bacillus spp.; Sphingomonas paucimobilis, and Aeromonas hydrophila)-(CM-4) was used to degrade and to decolorize triphenylmethane dyes. All bacteria were isolated from activated sludge extracted from a wastewater treatment station of a dyeing industry plant. Individual bacterial isolates exhibited a remarkable color-removal capability against crystal violet (50 mg/L) and malachite green (50 mg/L) dyes within 24 h. Interestingly, the microbial consortium CM-4 shows a high decolorizing percentage for crystal violet and malachite green, respectively, 91% and 99% within 2 h. The rate of chemical oxygen demand (COD) removal increases after 24 h, reaching 61.5% and 84.2% for crystal violet and malachite green, respectively. UV-Visible absorption spectra, FTIR analysis and the inspection of bacterial cells growth indicated that color removal by the CM-4 was due to biodegradation. Evaluation of mutagenicity by using Salmonella typhimurium test strains, TA98 and TA100 studies revealed that the degradation of crystal violet and malachite green by CM-4 did not lead to mutagenic products. Altogether, these results demonstrated the usefulness of the bacterial consortium in the treatment of the textile dyes.