Bioactive compounds from a haloalkalitolerant Streptomyces sp. EMSM31 isolated from Um-Risha Lake in Egypt | ||||
| Egyptian Journal of Aquatic Biology and Fisheries | ||||
| Article 20, Volume 26, Issue 2, March and April 2022, Page 307-330 PDF (1.26 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/ejabf.2022.229723 | ||||
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| Author | ||||
| Mervat A. Arayes et al. | ||||
| Abstract | ||||
| Wadi Al-Natrun, Egypt is considered an extreme environment, where, salinity and alkalinity are high. It was aimed in this work to explore such an environment for novel actinobacteria producing bioactive compounds. A total of 31 actinobacteria isolated from sediment of Um-Risha Lake at Wadi Al-Natrun were screened for antimicrobial activity against some Gram-positive and Gram-negative bacteria. The most potent isolate was identified based on the phenotypic and phylogenetic analyses using the 16S rRNA gene sequence and compared to those in the publicly available databases. It showed 99% similarity to Streptomyces violaceoruber strain EA169 and was identified as Streptomyces sp. EMSM31. The antimicrobial activity of this strain was assessed and was highly dependent upon the nutrients and conditions used for cultivation. Strain EMSM31 showed a broad spectrum antagonistic activity against both Gram-positive (Bacillus subtilis, Staphylococcus aureus) and Gram-negative (Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis) bacteria recording inhibition zones of 22, 18, 19, 19, and 18 mm, respectively. The maximal activity of secondary metabolite (23mm) was achieved in an optimized production medium containing fructose and yeast extract at pH7 on the fifth day of fermentation at 30°C. Moreover, gas chromatography-mass spectrometry (GC–MS) profiles of produced metabolites revealed apparent differences when compared to the public database of existing natural products. Analysis showed the presence of 3- hydroxy dodecanoic acid (19.49%) as a major compound. This study establishes that streptomycetes from extreme environments may be a rich reservoir for the production of biologically active compounds with pharmaceutical potentials. | ||||
| Keywords | ||||
| Streptomyces; Um-Risha Lake; Wadi Al-Natrun; antimicrobial activity; GC–MS analysis; bioactive compounds | ||||
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