Studies On Immobilized Yeast For Decolorization Of Azo Dyes
Dastagir, Sindhu Sameera, P. Naga Padma
Key words: Azo dyes, Mono-azo dye, yeasts, immobilization, dye decolorization.
Abstract: Azo dyes that are extensively used in textile industries are recalcitrant xenobiotic compounds causing a serious damage to the environment. Degradation of azo dyes being a necessity diverse dye dumped soils were screened for dye degrading yeasts. One efficient yeast isolate capable of decolorizing both mono-azo dyes and di-azo dyes was selected, immobilized by entrapment method and studied for decolorization efficiency. The isolate was morphologically, culturally and biochemically identified as Saccharomyces sp. Sodium alginate entrapped yeast cells were studied for decolorization of commercially available textile dyes having azo groups. The extent of colour removal in the culture medium was assessed through the decrease in dye absorbance of the supernatants. The immobilized yeast’s decolorization abilities were different and varied with inoculum size, incubation time and nutrients like carbon and nitrogen sources. The fermentation conditions like pH, temperature and aeration had no profound effect. The decolorization ranged from 70-100%. Complete decolorization was seen within 12 and 18 hrs depending on inoculum size. The immobilized beads with yeasts could be reused efficiently for three cycles. The dye degrading immobilized Saccharomyces isolate could be commercially significant as it is efficiently degrading both mono-azo and di-azo dyes, different dye waste waters in a semi-continuous manner and so could also be used for detoxification of industrial effluents.
. H.J .Knackmuss,”Basic Knowledge and Perspectives of Bioelimination of Xenobiotic Compounds”, Journal of biotechnology, 51, 287-295, 1996.
. C.I. Pearce, J.R. Lloyd & J.T. Guthrie, “The Removal of Color from Textile Waste Water Using Whole Bacterial Cells : A Review”, Dyes and pigments, 58, 179-196, 2003.
. I.M. Banat, P. Nigam, D. Singh & R. Marchant,” Microbial Decolorization of Textile Dye- Containing Effluents: A Review”, Bioresour Technol, 58, 217-227, 1996.
. T. Robinson, G. McMullan, R. Marchant & P. Nigam , ”Remediation of Dyes in Textile Effluent: A Critical Review on Current Treatment Technologies with a Proposed Alternative”, Bioresour. Technol. 77, 247-255, 2001.
. A. Stolz, “Basic and Applied Aspects in the Microbial Degradation of Azo Dyes”, Appl. Microbiol. Biotechnol, 56, 69-80, 2001.
. T. Zimmermann, F. Gasser, H.G. Kulla & T. Leisinger, “Comparison of Two Bacterial Azo-Reductases Accquired During Adaptation to Growth on Azo Dyes”, Arch Microbiol. 138, 37-43, 1984.
. M.A.M. Martins, M.H. Cardoso, M.J. Queiroz & M.T. Ramalho, “Biodegradation of Azo Dyes by the Yeast Candida zeylanoides in Batch Aerated Cultures, Chemosphere”, 38, 2455–2460, 1999.
. C. O’Neill, A. Lopez, S. Esteves, F.R. Hawkes, D.L. Hawkes & S. Wilcox, “Azo-Dye Degradation in an Anaerobic Treatment System Operating on Simulated Textile Effluent”, Appl. Microbiol. Biotechnol, 53, 249-254, 2000.
. Z. Aksu, “Application of Biosorption for the Removal of Organic Pollutants: A Review, Process Biochemistry, 40, 997-1026, 2005.
. A. Fernandes, A. Morao, M. Magrinho, A. Lopes & I. Goncalves, “Electrochemical Degradation of C.I.Acid Orange 7”, Dyes and Pigments 61, 287-296, 2004.
. F. Rafi, W. Franklin & C.E. Cerniglia, “ Azo-reductase Activity of Anaerobic Bacteria Isolated from Human Intestinal Microflora”, Appl Environ Microbiol, 2146-2151, 1990.
. K. Saraswathi & S. Balakumar,“Bio-Decolourization of n of Azodye (pigmented red 208) using Bacillus firmus and Bacillus laterosporus”, J Biosci Tech, 1, 1-7, 2009
. M.A.M. Martins, M.H. Cardoso, M.J. Queiroz & M.T. Ramalho, ”Biodegradation of Azo Dyes by the Yeast Candida zeylanoides in Batch Aerated Cultures, Chemosphere, 38, 2455–2460, 1999.
. D. Wesenberg, I. Kyriakides & S.N. Agathos, “White- Rot Fungi and their Enzymes for the Treatment of Industrial Dye Effluents”, Biotechnol Adv. 22, 161-187, 2003.
. T. Zimmermann, F. Gasser, H.G. Kulla & T. Leisinger, “Comparison of Two Bacterial Azo-Reductases Accquired during Adaptation to Growth on Azo Dyes”, Arch Microbiol. 138, 37-43, 1984.
. C.I. Pearce, J.R. Lloyd & J.T. Guthrie, “The Removal of Colour from Textile Wastewater Using Whole Bacterial Cells: A Review”, Dyes Pigments 58, 179-196, 2003.
. C. Kuo-Cheng, W. Jane-Yii, H. Chang-Cheng , L. Yu-Min & H. Sz-Chwun John, “Decolorization of Azo Dye Using PVA-Immobilized Microorganisms”, Journal of Biotechnology 101, 241-/252, 2003.
. S. Steffan, L. Bardi & M. Marzona, “Azo Dye Degradation by Microbial Cultures Immobilized in Alginate Beads”, Environ Int. 31, 201-205, 2005.