University of Tehran/Springer International Journal of Environmental Research 1735-6865 9 2 2015 04 01 Isolation of Extremely Heavy Metal Resistant Strains of Rare Actinomycetes fromHighMetalContent Soils in Iran 475 480 920 10.22059/ijer.2015.920 EN Journal Article 2015 04 24 Using of microorganisms to remove industrial pollutions of environment is an efficient method<br />that mimics natural process and decrease remediation cost. In this study, 450 actinomycete strains were<br />isolated from high metal content soils in Iran. Heavy metal salt solutions in different concentrations were used<br />to isolate the resistant strains. 40 resistant actinomycetes which they showed highly resistance to the most<br />applied heavy metals were selected. After examination of these strains in broth media with high levels of<br />metals, 13 resistant isolates were selected as high resistant actinomycetes. Some strains showed resistance to<br />140 mM ZnCl2, 7 mM CuSO4, 9.2 mM CdCl2, and 60 mM NiCl2. Molecular identification revealed that<br />resistant strains belonged to different actinomycetes genera including Streptomyces,Nonomuraea, Saccharothrix,<br />Streptosporangium and Promicromonospora which was the first report on occurrence of highly metal resistant<br />strains in Nonomuraea, Streptosporangium and Promicromonospora genera. Cadmium removal studies by<br />Promicromonospora sp. UTMC 2243 indicated 96.5% reduction in cadmium residual concentration, reflecting<br />cadmium removal capacity in Promicromonospora sp. UTMC 2243. https://ijer.ut.ac.ir/article_920_aef08becf144d74d75ca6c3f08d1ef68.pdf