ACCELERATED DEGRADATION OF SELECTED AZO DYES BY SOME MICROBIAL STRAINS

Abstract

This study involves aerobic decolorization of three reactive azo dyes: REACTIVE ORANGE 16, REACTIVE BRILLIANT RED K2BP AND REACTIVE BLACK B by newly isolated microbial strains. After optimization of reaction conditions bacterial strain B1 gave 73%, 74% and 84% decolorization, Bacterial strain B2 gave 85%, 77% and 78% decolorization while fungal strain gave 90.5%, 94% and 90.4% decolorization of REACTIVE BLACK B, REACTIVE ORANGE 16 and REACTIVE BRILLIANT RED K2BP respectively. No cometabolic role of any organic substrate was found. Color removal rates went on decreasing by addition of heavy metals. Cobalt and Nickel showed greater inhibitions on % decoloristion than zinc copper and iron there was about 50% color reduction by adding 6mg ml -1 of all heavy metals. Hydroquinone was proved to be a good redox mediator enhancing decolorization rate but only at lower concentrations. Biodegradation analysis was monitored by UV-VIS SPECTROSCOPY, HPTLC and GC/MS. None of the formed dye metabolite was from carcinogenic, toxic banned amines.