Thesis (Ph.D.) - Cairo University - Faculty of Pharmacy - Department of Microbiology and Immunology

Biological decolorization of dyeeffluent is receiving much consideration due to cost effective and its safety use. A total of 35 isolates (8 bacteria and 17 fungi) were recovered from waste waters by the enrichment culture technique, using Reactive black 5 (RB5) as a sole carbon source. A bacterial isolate (identified as Micrococcus luteus) showed the highest biodegradation activity. This isolate was able to remove up to 66% of the dye within 3 days of incubation. Comparatively, 53 % of the dye was decolourized by a yeast isolate (identified as Candida albicans) after 3 days of incubation. Addition of yeast extract at a concentration of 10 g l-1 enhanced the biodegradation, where complete disappearance of the dye was observed within 3 days of incubation. Interestingly, the bacterium was able to decolorize the dye up to a concentration of 40 mg l-1. The residual of the dye after degradation, was traced, where a metabolite was detected by TLC, UV absorbance as well as HPLC after 5 days of incubation by Micrococcus luteus. The metabolite was detected by TLC with Rf= 0.8 and a wavelength of 597 nm

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