Study of the Optimal Conditions for 〖Zn〗^(+2) Removal Using the Biomass of Isolated Bacteria from Ravang Mine

Environmental pollution consist of heavy metals is the most important environmental problems and leads to serious damage for human health. In order to reduce the harmful effects of heavy metals, their treatment methods should be developed, of which the use of biological absorbers are particularly important. The objective of this study was to isolate the -resistant bacteria from Ravanj lead- and zinc-Mine in Markazi Province and to find the most efficient strains for zinc adsorption. For this purpose, samples were collected from the mine sediments and the  resistant bacteria were enriched in the medium and isolated. After determining the resistance of isolated bacteria to , the most effective strain (MS3, Delftia lacustris) were detected by 16S rDNA sequencing. Then after the dried strains biomass was prepared and the effect of main operational variables such as, Zinc to Bacteria Biomass concentration ratio (), and the retention time of bacteria biomass in the Zinc medium on Zinc removal has been evaluated and analyzed using the response surface method and Box-Behnken model. A numerical optimization model was performed to obtain the maximum amount of Zinc removal from aqueous solution. Among the isolated strains, the MS3 (Delftia lacustris) was the most tolerance strain to the Zinc (1200 mg/l). The maximum percentage of Zinc removal based on the quadratic model was obtained at (means), (means Zinc to Bacteria Biomass concentration ratio of), and  (means). The maximum amount of Zinc removal percentages based on the experimental design and the simulated model were 9.86% and 9.49% respectively, indicating the high accuracy of the model. Therefore, the MS3 strains can be used as a bio-absorbent for Zinc removal.