Evaluation of parameters effective in nickel uptake by Pseudomonas and Bacillus

The heavy metal pollution has turned out to be one of the most important environmental problems. Due to their high stability in the presence of large amounts of wastewater factory، water treatment is necessary. In this study، Pseudomonas bacteria were isolated Ilam Town industrial waste water used as an example of Gram-negative bacteria. And Bacillus was isolated from desert dust Maranjab Kashan، as representative of Gram-positive bacteria Then، they were investigated in the biological uptake of nickel from aqueous solution in batch reactors. In this research، factors such as the rate of absorption of nickel، the effect of pH solution، metal reproducibility، metal uptake by Pseudomonas and Bacillus، were studied. Adsorption equilibrium time was approximately 10 minutes by Bacillus and the maximum metal uptake by the bacteria was 0. 71 mmol/g dry weight of cells. Discussion and Nickel uptake by Pseudomonas was about 0. 12 mmol/g dry weight cell mass and the equilibrium time was about 5 minutes. Best nickel release factors were Bacillus and Pseudomonas، respectively، of EDTA and nitric acid. The results showed that gram-positive bacterium Bacillus was a better choice for the removal of nickel from contaminated solutions.