Microbiological Perspective on the Interaction of Microorganisms with Uranium

BACKGROUND AND OBJECTIVESToday, the safe removal and recovery of radionuclides and heavy metals from the contaminated sources and ores has become a valuable issue in the environmental field. Normally, there are different methods for their removing and recovery, which are divided into two Techniques: biological methods and non-biological methods. Bioremediation and biorecovery are the growing methods with an increasing trend in studies and practical uses for the recovery and removal of radionuclides and metals. They are mentioned as the green methods (an energy-efficient, eco-friendly and efficient method). Microorganisms are known to have an important effect on the environmental fate of metals and uranium through physicochemical and biological mechanisms and can affect their toxicity and solubility. Understanding the interaction of microorganisms with uranium will be useful for the efficient treatment of radioactive waste, etc. The biological methods depend on the presence of suitable microorganisms and their appropriate performance in environmental conditions. Therefore, the use of microorganisms adapted to each environment is the most important practical approach to achieve the optimizing the processes. Microorganisms that grow in extreme environments have been shown to be remarkably resistant to a wide range of extreme conditions in many cases.MATERIALS AND METHODSOxidation, bioaccumulation, biosorption, bioreduction and bioprecipitation can be mentioned among the interactions between microorganisms and uranium that have role in mobility and immobility of this radionuclide in the environment. Understanding the optimal conditions of uranium-microorganism interactions, including environmental conditions affecting the process, is needed to develop knowledge of the biological technique. Also, the process of targeted screening and isolation of new microorganisms with unique characteristics from the environments contaminated with radionuclides is useful in these studies.RESULTS AND DISCUSSIONToday, it has been proven that these microbial interactions have a good potential to replace the conventional methods of removing and separating metals and radionuclides from the environments. Several reports showed that indigenous microbes in the places contaminated with toxic metals can be more tolerant to toxic metals. Today, a wide range of microorganisms ۲۴have been identified from mines and contaminated places that can remove or immobilize uranium. It has been determined that the interactions of these biological agents with uranium can lead to uranium removal and recovery from the environments. So according to the reports, it is possible to isolate the new microbial isolates from the specific environments, which are very useful for removing and recovery of uranium.CONCLUSIONThe abundance and diversity of microorganisms in environments contaminated with uranium and radionuclides and their resistance to the pollutants and their superior removal and recovery capacities have led to the high importance of identifying metal-resistant microbial populations and determining their metal removal/recovery potential.

کلیدواژه ها:

Bacteria ، Biomining ، Bioremediation ، Radionuclides ، Uranium