Effects of Co-substrates on Biodegradation of Azo Dyes: A case study of Marine Bacteria

Presence of colour in water will make it unsuitable for human consumption. Textile industries have the major role in imparting colour in natural water bodies as their outlets are opened to them. These industries rely upon azo dyes as it impart brilliant colour to fabrics. But its presence in water bodies creates serious problems. Structure of an azo compound is a very important factor to be considered during the treatment of colored wastewater as it seriously affects the decolorization performance of microbial cultures. Since azo compounds have less carbon content, co-substrates can make good the deficiency. This study was carried out to find the efficacy of marine bacterial strains to degrade two selected azo dyes (congo red and methyl red) on giving three co-substrates (starch, glucose and mannitol). For decolourization of congo red, starch was found to be the best co-substrate (79.2% to 93% decolourization) and of methyl red, mannitol (50% strains shows >90% decolourization) was found to achieve best results. The decolourisation potential and growth of majority of the strains in methyl red was found to get reduced in the presence of starch. Next to mannitol strains utilise glucose (>50 % decolorisation).