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Abstract

Halophilic microorganisms have important roles in bioremediation and transformation of the toxic metal compounds in polluted environments. Identification of toxic metal tolerant strains is the first step in applying them in bioremediation processes. In these investigations 90 strains of bacteria were isolated from various salty environments (soil, water and waste water) in Iran. Among them, moderately halophiles and halotolerants were 49 and 41 strains respectively. The resistance patterns, expressed as MIC, to the toxic oxyanion of K-tellurite at 34°C and 168 incubation period were determined( 0.1 up to 16mM), by using agar dilution method. Minimum Inhibitory Concentrations (MIC) of the CHW1 (salt tolerant) and the QW5, QW6 (halophilic), showed maximum resistance to K-tellurite (16, 10 and 12mM respectively). The impacts of salinity (1,5,10,15%w/v NaCl) and various concentrations of the selenooxyanions(5,10,20 ,25,50,75,100 mM) on the toxicity of the K-tellurite were determined. Tellurite MICs in QW5 and QW6 were highered but in the CHW1 was lowered when the NaCl concentrations were increased from 1% to 10%.When K-tellurite was used plus Na-Selenite, the results obtained showed that the MIC in the halophilic strains were increased significantly, whereas, it was decreased considerably in the salt tolerant strain.

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