Abstract
In this study, 150 soil samples were collected from several locations of Riyadh desert areas in Saudi Arabia. Samples were prepared for isolation using the standard serial dilution method on tap water agar (TWA) medium. 150 isolates of actinomycetes, isolated from the samples were tentatively identified as streptomycetes based on their phenotypic and biochemical characteristics. All purified isolates exhibited a range of about 15 streptomycetes like color groups on yeast extract-starch soluble (YS) agar medium including grey series, white series, brown series and yellow series. Further, scanning electron microscopic studies of the strains showed the different morphology of the aerial mycelium on YS agar medium. These morphological structures and cell wall diaminopimelic acid test have tentatively proved that almost all the selected isolates were under the genus Streptomyces in the family Streptomycetaceae. This is the first intensive study and we confirmed that the desert soil of Saudi Arabia is good sources for the isolation of diverse streptomycetes. More intensive study will be conducted on the isolated streptomycetes strains to utilize as biocontrol agents and there is a probability of finding new streptomycetes species in unexplored soil samples in Saudi Arabia as indicated by its unique diversity.