RESUMO
Forty bacterial isolates belonging to Actinomycetes were obtained out from 6 soil samples. These Samples were collected from Al-Muray'iyah Al-Thaleth and Hawijat Sageur sites both located within the lands of the Agricultural Research Center in Dair Al-Zour. A process of primary screening was applied on these isolates by studying their bioactivity against some harmful bacterial species both gram-positive [S. aureus] and gram-negative [V. fluvialis], K. pneumoniae, E. coli, and P. aeruginosa]. Results showed that there are 15 bacterial isolates [37.5% of the whole isolates] able to produce antibiotics, they caused an inhibition to tested bacteria. The isolates where clustered according of their effectiveness as following: 4 isolates were effective against gram-positive bacteria, 4 isolates were effective against gram-negative bacteria, whereas, 7 isolates showed bioactivity against both gram-positive and gram-negative bacteria at the same time. 4 isolates was distinct by their high yield of antibiotics out of all the isolates. The potentiality of these 4 isolates were tested in order to recognize the most efficient one production of antibiotics, and to conduct further studies on it. The isolate MH11 preceded other isolates by their ability to produce antibiotics. Various morphological and biochemical essays showed, that this isolate belongs to the genus Streptomyces