Isolation and screening of bacteria capable of decolorizing Azo dyes

Faisalabad is known as a city of textile not only in Pakistan but also all over the world. Several textile processing units are in operation in the surroundings of the city, which are releasing a substantial amount of azo dyes into the wastewater streams in the surroundings of these textile units.The discharge of these contaminants is considered to be a potential threat to the environment because of their hazardous nature. Thus, this study was undertaken to isolate the bacteria possessing high potential to degrade azo dyes from the wastewater discharged by the textile units. A total of 150 bacterial strains were isolated from these wastewater samples using minimal salt medium spiked with Reactive Blue ZBLN azo dye. Results revealed that some bacterial strains were able to decolorize 8 different dyes almost within 6 hours. Thus, the isolated bacterial strains have the potential to remove a variety of dyes from the liquid culture, which could be used to develop a biotreatment strategy for cleanup of the industrial wastewater prior to their discharge into wastewater streams of the surrounding area.