Biodegradation of malachite green by a novel copper-tolerant Ochrobactrum pseudogrignonense strain GGUPV1 isolated from copper mine waste water

摘要

Background: Malachite green (MG) is a triphenyl methane cationic dye which is used to color fabrics and is employed as food additive, food coloring agent and medical disinfectant. MG is found to be toxic to aquatic organisms, animals including humans. Copper is a commonly found metal in environment due to anthropogenic activities. Most of the microorganisms show sensitivity toward it. This adversely affects their growth and activity. In the present study, biodegradation of MG by a copper-tolerant bacterium has been investigated. Biodegradation was confirmed by UV-Vis and FTIR spectroscopy. The metabolites generated after degradation of MG were identified by LC/MS and a plausible pathway of MG degradation has been elucidated. Microbial and phyto toxicity of generated metabolites were also evaluated. Results: A strain belonging to Ochrobactrum pseudogrignonense strain GGUPV1 was discovered from copper mine waste water. This bacterium could tolerate as high as 50 mM copper sulfate in minimal medium. It was observed that this bacterium could degrade 400 mg/L of MG in minimal medium. Decolorization of MG was also observed in presence of copper sulfate in the medium. Degradation of MG was confirmed by UV-Vis and FTIR spectroscopy. GC/MS study indicated that metabolites generated after degradation of MG were nontoxic to Staphylococcus aureus. Conclusions: This is the first report showing degradation of MG by Ochrobactrum pseudogrignonense. This strain can be successfully employed for degradation of MG.