American Journal of Microbiological Research. 2014, 2(1), 16-23DOI:
Abstract: A bacterial strain ETL-1979, identified as Bacillus spp. was isolated from activated sludge of textile wastewater treatment plant in Ankleshwar, Gujarat, India. Azo dyes constitute the largest and most versatile class of synthetic dyes. Biological decolorization of azo dyes occurs efficiently under low oxygen to anaerobic conditions. However, this process results in the formation of toxic and carcinogenic amines that are resistant to further detoxification under low oxygen conditions. Moreover, the ability to detoxify these amines under aerobic conditions is not a wide spread metabolic activity. In this study we describe the use of Bacillus spp. ETL-1979, isolated from an activated sludge process of a textile company, for the sequential decolorization and detoxification of the azo dyes Reactive Yellow 107, Reactive Black 5, Reactive Red 198 and Direct Blue 71. Tyrosinase activity was observed during the biotreatment process suggesting the role of this enzyme in the decolorization and degradation process, but no-activity was observed for laccase and peroxidase. Toxicity, measured using Daphnia magna, was completely eliminated.