Decolourization and Detoxification of Malachite Green by Enterobacter cloacae NAM-۹۴۱۵ Isolated from Flower Vase Water

Introduction: The appalling environmental hazards associated with the use of a triphenylmethane dye i.e., Malachite Green (MG) was unveiled by the National Institute of Health in ۲۰۰۴. However, in spite of the successful ban of MG in the US, UK, and several European countries, it continues to be the most commonly used dye in microbiological laboratories and a few textile industries. In the present study, the bio-remediation potential of a bacterium isolated from a flower vase filled with traces of MG dye solution was investigated.Materials and Methods: The physicochemical parameter for degradation of MG was optimized. Also, considering the fact that the dyes are complex molecules and their breakdown products may be unsafe for environmental disposal, toxicity tests were carried out using an aquatic invertebrate (Daphnia magna) as a model organism.Results: The bacterium was identified as Enterobacter cloacae NAM-۹۴۱۵ by ۱۶S rRNA analysis. It showed ۹۶% decolourization of MG at ۵۰۰ ppm dye concentration when cultured at optimum conditions of incubation i.e., ۱۵ h at ۴۵ °C under shaker (۱۲۰ rpm) conditions using nutrient broth medium (pH ۷). In addition, it also showed tolerance to high salt concentrations of up to ۶g%. Moreover, the breakdown products supported the growth of daphnids in our study.Conclusions: The above observations indicate the suitability of E. cloacae NAM-۹۴۱۵ for biodecolorization of textile effluents. 

کلیدواژه ها:

Decolourization ، Detoxification ، Malachite Green ، Enterobacter cloacae NAM-۹۴۱۵ ، Toxicity tests