Evaluation of lead metal biosorption by Rhodococcus erythropolisPTCC۱۷۶۷

BACKGROUND AND OBJECTIVESRemoval of heavy metals from the environment due to industrial activities is of grave concern due to the toxicity of these metals in humans and other forms of life. Among the toxic heavy metals, lead is in the limelight due to its major environmental impact. Microbial biomass has been identified and documented as an effective factor in metal removal. This work is to determine the biological uptake of lead by Rhodococcus erythroplis.MATERIALS AND METHODSA strain of Rhodococcus erythropolis was prepared by the Microbial Bank of Iran Scientific-Industrial Research Organization number ۱۷۶۷. The Minimum inhibitory concentration(MIC) for lead metal is measured. Made of stock lead metal. Cells are collected at the end of the exponential phase and then centrifuged. The culture medium discharged and the cell mass was washed three times with saline solution. The biomass was autoclaved at ۱۲۱ ◦C for ۲۰ min and dried in an oven at ۱۰۵ ◦C for ۱۲ h. Specific concentrations of lead metal were prepared. ۰.۰۱ g of dead bacteria sediment was added to the culture medium and metal and placed in an incubator shaker. After ۲۴, ۴۸, and ۷۲ hours, ۱۰ cc of the medium was centrifuged using a refrigerated centrifuge. A supernatant was used to read spectrophotometric and atomic absorption spectrometers.RESULTS AND DISCUSSIONThe MIC value for lead metal is۲۵۰μg/ml. For the lead element, it happened in ۲۴ hours and at a concentration of ۲۰۰ ppm with ۹۹.۷% by the bacterium Rhodococcus erythropolis. The presence of organic compounds, such as carboxylic acids, amides, and ketones, is available for capturing lead ions.CONCLUSIONIn this study, Rhodococcus erythropolis showed the ability of bioremediation of lead metal, considering that ecosystem pollution caused by heavy metals poses many risks to human health and other living organisms, as a result, using bioremediation to remove metals can To solve the limitations and problems related to physical and chemical methods.

کلیدواژه ها:

Biosorption ، Lead metal ، Rhodococcus erythropolis PTCC۱۷۶۷