RESUMO
Various isolates of streptomycetes spp. obtained from different localities of Baghdad soils were tested for their antimicrobial activities. Five isolates showed the highest antimicrobial potentialities in the culture broth. The isolate AR1 was the most active one and thus was selected for identification. Morphological, cultural, physiological, biochemical characteristics and biological properties as well as enzymatic activities and cell wall composition suggested that the isolate is belonging to the genus Streptomyces. The 16S ribosomal DNA amplification for phylogenetic study revealed that the isolate was highly related to Streptomyces tendae [99%], so it is designated as Streptomyces tendae AR1. This new strain is capable of producing antimicrobial agent[s], which is active in vitro against Gram+ve and Gram-ve bacteria [Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus. Escherichia coli and Pseudomonas aeruginosa], yeasts [Candida albicans, Candida pseudotropicalis and Rhodotorula minuta] and fungi [Aspergillus flavus, Aspergillus niger, Aspergillus terreus, Botrytis allii, Diplodia oryzae, Fusarium oxysporum, Helmenthosporum turcicum, Machrophomina phaseoli and Trichoderma viride]