Filamentous bacterial belonged to Streptomyces species were novel drug source for medical and industrial applications. However, the detailed identification of Streptomyces species from Saudi Arabian extreme environment for the identification novel drug source for medical and industrial applications were rarely studied. The Streptomyces strain Al-Dhabi-2 obtained from the thermophilic region kingdom of Saudi Arabia, exhibited antimicrobial potentials against the pathogenic microorganism were characterized. Biochemical and phylogenetic analysis confirmed that the strain was closely associated to the Streptomyces species. The chromatogram of GC-MS analysis of this ethyl acetate extract (EA) had diverse of chemical compounds namely benzene acetic acid (7.81%), acetic acid, methoxy-, 2-phenylethyl ester (6.01%) were the major compounds. EA of Al-Dhabi-2 showed inhibition zone ranged from 14 to 25 mm at 5 mg/well concentration against the tested microbial pathogens. Results revealed that the significant MIC values were observed against B. cereus, and E. faecalis by (less than 39 μg/ml) and against S. agalactiae with (78 μg/ml). Minimum inhibitory concentrations (MIC) for fungi: were also reported against Cryptococcus neoformans and Trichophyton mentagrophytes by (156 μg/ml), whilst Candida albicans and Aspergillus niger by (312 μg/ml). Results of this study showed that thermophilic actinobacteria could be promise source in the context of searching for unique antimicrobial agents with novel properties.
Keywords: 16S rRNA gene; Antimicrobial activity; GC-MS; Hot spring; Thermophilic Streptomyces.