Decolourization of Azo Dyes and Dye Industry Effluents by Lignin Degrading Fungus Trametes versicolor

Lignin degrading white rot fungus, Trametes versicolor isolated from the logs of Acacia nilotica L.Del.sp. indica in the Western Ghats region of Tamil Nadu, India. The fungus was used for the decolourization of azo dyes such as orange G, congo red and amido Black 10 B and also for colour removal from the dye industry effluents. Batch studies were conducted in a defined medium with pH-4.5. The results revealed that the fungus could remove only 34.60% of orange G in the synthetic solution whereas 98.27% and 78.05% removed congo red and amido black 10B respectively. An enzymatic dye decolourization study showed that a maximum of 21% orange G was removed by lignin Peroxidase (LiP) at 15 U/ml whereas manganese dependant peroxidase (MnP) and laccase at the same concentration decolorized at 13.5% and 8.10%. A maximum decolourization of 13.5% and and 12.5% for Congo red and amide Black 10B, respectively, was recorded by laccase. Maximum decolourization of the effluent by this fungus was evidenced on fouth day treatment .On the fourth day the colour removal was up to 98.43%. From the results, it was interpreted that the colour removal by the basidiomycetes fungi was mainly due to adsorption of the dyes to the mycelial surface and also due to metabolic breakdown. The results suggested that the batch mode treatment of Trametes versicolor is one of the most efficient ways for colour removal in dye industry effluents.