Abstract:
Streptomycetes from the semi arid rhizospheric soils are a rich resource of novel secondary metabolites
with various biological activities.
The aims of the present study are to identify culturable streptomycetes from the rhizospheric soil by
16S rRNA gene, evaluate the antimicrobial activities of isolates and detect the bioactive secondary
metabolites from selected streptomycetes, extraction and identification of the bioactive compounds.
A total of 65 strains were isolated from rhizospheric soil sample. Two of themes (SFKH10 and
SFKH4) were analyzed by 16S rRNA gene sequencing. The crude cell extracts out of the two strains
showed antibacterial and antifungal activities. Ethyl acetate crude extract of cultured SFKH10 strain
was subjected to online high-performance liquid chromatography (HPLC)-electrospray mass
spectrometry (ESI-MS) for metabolite profile analyses as well as molecular weight determination. The
extract was dissolved in methanol (1 mg/ ml) and then analysed by a Hewlett–Packard HP1100 HPLC
UV Diode Array detector (DAD), online coupled to an Esquire-Bruker–Daltonics ion trap mass
spectrometer using a reversed-phase column on the analytical scal. Finally, a compound dinactine
was isolated from Streptomyces coeruleorubidus SFKH10 strain by using chromatography techniques,
UV, HR-ESI-MS and NMR, and their antimicrobial activities against the test bacteria and fungus were
also evaluated. In addition, the partial characterization of the molecules secreted by S. spororaveus
SFKH4 strain has shown its capacity to produce a large variety of complexes compounds having high
molecular weight.
In conclusion, the present study has revealed the potential of semi-arid Algerian ecosystems as a good
source for bioactives molecules-producing actinobacteria
