Decolorization of Malachite Green Dye Solution by Bacterial Biodegradation

Malachite green dye is widely used in food and textile industries for various purposes and also used as biocide in the aquaculture industry to control fungal attacks and protozoan infections. Surface and ground water is contaminated by dyes due to discharge of untreated wastewater from industries. The presence of malachite green in water causes serious health effects such as mutagenesis, respiratory toxicity and carcinogenesis. Therefore, removal of malachite green from water by using various techniques is an essential concern for living beings as well as environment. In this study, the ability of isolated bacteria (from oil contaminated soil) for biodegradation of MG dye was investigated. The bacterium was able to grow in temperature range of 25 to 45°C and pH range of 5 to 9. Optimum temperature and pH for bacterial growth were determined as 37 °C and 7, respectively. Effect of temperature, initial concentration of dye and shaking condition on decolorization of dye solution was also tested. 20 ppm MG dye was efficiently degraded by bacteria in less than 2 h, and biodegradation of MB dye followed first-order kinetics model. These properties make the bacteria suitable for industrial wastewater treatment.