Optimization Study of Nickel and Copper Bioremediation by Microbacterium oxydans Strain CM3 and CM7

Bioremediation as a low-cost technique can reduce the toxicity of metal ions from the contaminated site including soil and water. In this study, the copper (Cu) and nickel (Ni) bioremediation potential of Microbacterium oxydans strains CM3 and CM7 was investigated under different ranges of environmental factors including pH, temperature, and initial metal concentration by response surface methodology. The coefficients of the regression equation were calculated based on the removal of Cu and Ni by isolated strains. Analysis of variance illustrated a high value of R-2 for the removal of Cu and Ni by strains CM3 and CM7. The results showed that the percentage of Cu and Ni removal increased with increasing temperature and decreasing pH at low concentration of metal ions. In addition, Cu and Ni were highly removed at pH 5-6 and temperature 36-40 degrees C. Under optimal ranges of the used parameters, the maximum removal percentages of Cu and Ni by strains CM3 and CM7 were 94.15%, 91.11%, 86.32%, and 83.24%, respectively. This study indicates that M. oxydans strains CM3 and CM7 could be used as a powerful alternative to other expensive methods that are used to remove metal ions.