ماندانا زارعی

Introduction:. The aim of this study was screening and isolation of sponge associated actinomycetes with potential antibiotics production in Persian Gulf. Methods: Marine sponge Haliclonia simulans was collected from coastal waters of Kharko Island in Persian Gulf. To avoid cross contamination, only unbroken samples were used for microbiological analysis. 1 cm3 of sponge tissue was excised and homogenized with phosphate buffered saline. The resultant was serially diluted and pours plated in three isolation media that formulated in this reasearch. The plates were kept for incubation at 25 to 30 ?C for one week. Then the Actinomycetes isolates were purified by pure culture techniques. Preliminary screening of Actinomycetes for antibacterial activity was done by modified cross-streak method. Eleven isolated strains were inoculated on modified Emerson agar plates by single streak in the center. The plates were incubated at 30 ?C for 3 days. Seven bacteria consist of Proteus mirabilis, Micrococcus luteus, Escherichia coli, Staphylococcus aureus, Enterococcus faecialis, Streptococcus salivaris and pseudomonas aeruginosa were used as test organism. The results of the present investigation reveal that modified Emerson agar was the best culture medium and all those eleven isolates were active against at least three of the test bacteria. Conclusion: the Actinomycetes that isolate in this study have the potential for more investigation to obtain novel antibiotics.