Optimization of significant factors on the microbial decolorization of azo dye in an aqueous medium by Design of Experiments

Document Type : Original Research Paper


1 Department of Microbiology, Periyar University, Salem - 636 011, Tamil nadu, India.

2 Department of Microbiology, DKM College for Women, Vellore – 632 001, Tamil nadu, India.


Currently, the reduction of reactive dyes present in the textile effluent is a big challenge due to the threat to the environment. Existing physical and chemical methods contains many drawbacks. In the present scenario microbial reduction pays much attention and current focus of research. Therefore, the present study isolated dye decolorizing bacterium Exiguiobacterium aurantiacum (TSL7) from activated sludge and identified by molecular techniques and 16S rDNA sequences. Decolorization was not established in Bushnell hass broth composition in accordance with absence of carbon and nitrogen source. The three environmental factors pH, starch and beef extract were selected from Plackett-Burman design experiments. The central composite design was employed to optimize the maximum removal of remazol golden yellow (91.83%) with pH, 6.89, starch, 0.49% (w/v) and beef extract 0.67% (w/v) respectively, These key factors playing a major role in the bacterial dye removal and the interactions were evaluated statistically. The optimal value of significant factors supports to maximize the dye removal competency of isolated bacterium. Thus results exhibited that local salt tolerant bacterium Exiguiobacterium aurantiacum (TSL7) could be a potential candidate for an in situ-bioremediation of inorganic salts abundant textile effluents in the textile industry.


Amoozegar, M. A., Hajighasemi, M., Hamedi, J., Asad, S. and Ventosa, A. (2011). Azo dye decolorization by halophilic and halotolerant microorganisms. Ann. Microbiol., 61(2); 217-230.
Arun Prasad, A. S. and Bhaskara Rao, K. V. (2013). Aerobic biodegradation of Azo dye by Bacillus cohnii MTCC 3616; an obligately alkaliphilic bacterium and toxicity evaluation of metabolites by different bioassay systems. Appl. Microbiol. Biotechnol., 97(16); 7469-7481.

Babu, B. R., Parande, A. K., Raghu, S. and Kumar, T. P. (2007). Cotton textile processing: waste generation and effluent treatment. J. Cotton. Sci., 11; 141-53.

Chen, B. Y., Hsueh, C. C., Chen, W. M. and Li, W. D. (2011). Exploring decolorization and halotolerance characteristics by indigenous acclimatized bacteria: Chemical structure of azo dyes and dose-response assessment. J. Taiwan Inst. Chem. Eng., 42(5); 816-825.

Dos Santos, A. B., Cervantes, F. J. and Van Lier, J. B. (2007). Azo dye reduction by thermophilic anaerobic granular sludge, and the impact of the redox mediator anthraquinone-2, 6-disulfonate (AQDS) on the reductive biochemical transformation. Appl. Microbiol. Biotechnol., 64(1); 62-69.

Du, L. N., Yang, Y. Y., Li, G., Wang, S., Jia, X. M. and Zhao, Y. H.  (2010). Optimization of heavy metal-containing dye acid black 172 decolorization by Pseudomonas sp. DY1 using statistical designs. Int. Biodeterior. Biodegrad., 64(7); 566-573.
Dubrow, S. F., Boardman, G. D. and Michelsen, D. L. (1996). Chemical pretreatment and aerobic–anaerobic degradation of textile dye wastewater. (In A. Reife & H.S. Freeman (Eds.), Environmental Chemistry of Dyes and Pigments (pp. 75-102). New York: Wiley.)
El Bouraie, M. and El Din, W. S. (2016). Biodegradation of Reactive Black 5 by Aeromonas hydrophila strain isolated from dye-contaminated textile wastewater. Sustainable Environment Research., 26(5); 209-216.
Feng, C., Fang-yan, C. and Yu-bin, T. (2014). Isolation, Identification of a Halotolerant Acid Red B Degrading Strain and Its Decolorization Performance. APCBEE Procedia., 9; 131-139.
Georgiou, D., Hatiras, J. and Aivasidis, A. (2005). Microbial immobilization in a two stage fixed-bed-reactor pilot plant for on-site anaerobic decolorization of textile wastewater. Enzyme and Microbial Technol., 37(6); 597-605.
Ghodake, G. S., Telke, A. A., Jadhav, J. P. and Govindwar, S. P. (2009). Potential of Brssic juncea in order to treat textile effluent contaminated sites. Int. J. Phytoreme., 11(4); 297-312.
Gopinath, K. P., Kathiravan, M. N., Srinivasan, R. and Sankaranarayanan, S. (2011). Evaluation and elimination of inhibitory effects of salts and heavy metal ions on biodegradation  of congo red by Pseudomonas sp. mutant. Bioresour. Technol., 102(4); 3687-3693.
Guadie, A., Tizazu, S., Melese, M., Guo, W., Ngo, H. H. and Xia, S. (2017). Biodecolorization of textile azo dye using Bacillus sp. strain CH12 isolated from alkaline lake. Biotechnol Rep., 15(6); 92-100.
Jadhav, S. U., Jadhav, M. U., Kagalkar, A. N. and Govindwar, S. P. (2008). Decolorization of Brilliant Blue G Dye Mediated by Degradation of the Microbial Consortium of Galactomyces geotrichum and Bacillus sp. J. Chin. Inst. Chem. Engrs., 39; 563-570.
Jadhav, U. U., Dawkar, V. V., Ghodake, G. S. and Govindwar, S. P. (2008). Biodegradation of direct red 5B, a textile dye by newly isolated Comamonas sp. UVS. J. Hazard. Mater., 158(2-3); 507-516.
Kalpana, D., Velmurugan, N., Shim, J. H., Oh, B. T., Kalaiselvi, S. and Lee, Y. S. (2012). Biodecolorization and biodegradation of reactive Levafix Blue E-RA granulate dye by the white rot fungus Irpex lacteus. J. Environ. Manage., 111; 142-149.
Khalid, A., Arshad, M. and Crowley, D. E. (2008). Decolorization of azo dyes by Shewanella sp. under saline conditions. Appl Microbiol Biotechnol., 79(6); 1053-1059.
Khan, R., Bhawana, P. and Fulekar, M. H. (2012). Microbial decolorization and degradation of synthetic dyes: a review. Rev Environ Sci Biotechnol., 12(1); 75-97.
Khelifi, E., Touhami, Y., Dhia Thabet, O. B., Ayed, L., Bouallagui, H., Fardeau, M. L. and Hamdi, M. (2012). Exploring bioaugmentation strategies for the decolourization of textile wastewater using a two species consortium (Bacillus cereus and Bacillus pumilus) and characterization of produced metabolites. Desalin. Water Treat., 45(1-3); 48-54.
Kaur, B., Kumar, B., Garg, N. and Kaur, N. (2015). Statistical Optimization of Conditions for Decolorization of Synthetic Dyes by Cordyceps militaris MTCC 3936 Using RSM. Biomed Res Int., 536745; 1-17.
Kim, T. Y., Min, B. J., Choi, S. Y., Park, S. S., Cho, S. Y. and Kim, S. J. (2008). Separation characteristics of reactive orange dye from aqueous solution using biosorbent. Proceeding of the World Congress on Engineering and Computer Science, Sanfrancisco, USA.
Kuhad, R. C., Sood, N., Tripathi, K. K., Singh, A. and Ward, O. P. (2004). Development in microbial methods for the treatment of dye effluents. Adv. Appl. Microbiol., 56: 185-213.
Lalnunhlimi, S. and Krishnaswamy, V. (2016). Decolorization of azo dyes (Direct Blue 151 and Direct Red 31) by moderately alkaliphilic bacterial consortium. Braz J Microbiol., 47(1); 39-46.
Nigam, P., Banat, I. M. and Marchant, R. (1996). Decolorization of effluent from the textile industry by a microbial consortium. Biotechnol. Lett., 18(3); 117-20.
Okeke, B. C. (2008). Bioremoval of hexavalent chromium from water by a salt tolerant bacterium, Exiguobacterium sp. GS1. J. Ind. Microbiol. Biotechnol., 35(12); 1571-1579.
Pearce, C. I., Lloyd, J. R. and Guthrie, J. T. (2003). The removal of colour from textile wastewater using whole bacterial cells: a review. Dyes. Pigm., 58(3); 179-196.
Solis, M., Solis, A., Perez, H. I., Manjarrez, N. and Flores, M. (2012) Microbial decolouration of azo dyes: a review. Process. Biochem., 47(12); 1723-1748.
Van der Zee, F. P. and Villaverde, S. (2005). Combined anaerobic - aerobic treatment of azo dyes-a short review of bioreactor studies. Water Res., 39(8); 1425-1440.
Vandevivere, P. C., Bianchi, R. and Verstraete, W. (1998). Treatment and Reuse of Wastewater from the Textile Wet-processing Industry: Review of Emerging Technologies. J. Chem. Technol. Biotechnol., 72(4); 289-302.
Yan, B., Du, C., Xu, M. and Liao, W. (2012). Decolorization of azo dyes by a salt-tolerant Staphylococcus cohnii strain isolated from textile wastewater. Front. Environ. Sci. Eng., 6(6); 806-814.
Zhuang, X., Han, Z., Bai, Z., Zhuang, G. and Shim, H. (2010). Progress in decontamination by halophilic microorganisms in saline wastewater and soil. Environ. Pollut., 158(5); 1119-1126.