Research - MS (Thesis)

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Title: An Approach to Biological Treatment of Tannery Effluent in Bangladesh: Microorganisms of Tannery Dye

Author: Sumon Chandra Nath

Supervisor: Md. Abul Manchur and Md. Maruf Hossain

Research Field: Environmental Microbiology

Batch: 10th

Session: 2009-2010


Abstract

Dyes are the most important group of synthetic colorants. They are generally considered as xenobiotic compounds which are very recalcitrant to biodegradation. About 10% - 15% of the total dyes used in the leather industry are released into the environment during the manufacturing and usage. Some dyes and some of their N-substituted aromatic bio-transformation products are toxic and/or carcinogenic and therefore these dyes are considered to be environmental pollutants and health hazards. These dyes can be degraded by physico-chemical and biological methods. Of these, biological methods are considered to be the most economical and efficient. In this work, attempts were made to degrade these dyes aerobically and anaerobically. The organisms which were efficient in degrading the dyes are isolated from different sections of tannery wastewater treatment plant. They are identified and characterized by following the “Bergey’s Manual of Bacteriology”, by Buchanan and Gibbons (8th edition) for bacteria and “A Manual of Soil Fungi”, by Joseph C. Gilman (2nd edition) for fungi. Then the efficiency of dye degradation by individual microorganism and by consortium was analyzed in presence of various co-substrates, such as glucose, dextrose and starch as carbon source; and peptone and yeast extract as nitrogen sources. The environmental factors, such as, aeration, temperature and pH; and their effects on dye degradation have also been studied. It was found that mixed cultures of bacteria from tannery treatment plant worked efficiently in degrading the dyes.