Exploring the Antimicrobial Potential of Streptomyces Isolates from Padina pavonica: A Marine Bioprospecting Study
Ahmed A. Moubarak ,Mervat G. Hassan, Ahmed A. Hamed,Mostafa A. Lamada
This study focuses on the exploration of bioactive compounds from the brown macroalgae Padina pavonica collected from the deep-sea waters of Hurghada, Red Sea, Egypt. The distinct morphological features of Padina pavonica, including slender, foliate, and planar fronds in the young stage, and increased thickness with a concave form in mature fronds, were characterized. Delicate hairs on external surfaces, slime-coated internal surfaces, and sparse calcification with inward-curving edges further define this alga.
Endophytes, specifically twelve streptomyces strains, were isolated from the sterilized surfaces of sponge and algae fragments collected from the Red Sea. Isolation techniques involved immediate tagging and transportation to the laboratory, followed by storage in sterile polyethylene bags at 4°C. Actinomycetes were isolated within 24 hours using a serial dilution method based on distinct colony morphology and color variations. Purification was achieved through repeated streaking on ISP-2 medium subculture plates, leading to the isolation of strains coded as 36X, 37X, 38X, and 39X.
The subsequent fermentation of isolated actinomycetes on rice medium in Erlenmeyer flasks yielded bioactive components. Ethyl acetate was employed for the extraction of crude extracts, which were then subjected to antimicrobial screening using the agar disc diffusion method. Isolate 36X exhibited significant antimicrobial activity, particularly against Staphylococcus aureus and Pseudomonas aeruginosa. Isolate 37X displayed moderate activity against both bacteria and fungi (Candida albicans and Aspergillus niger). Conversely, Isolates 38X and 39X did not exhibit significant antimicrobial activity. These findings highlight the diverse antimicrobial capabilities of the isolated compounds, emphasizing the potential applications of Isolates 36X and 37X in combating infections caused by specific microorganisms. Further research, including concentration variations and additional assay methods, is essential to elucidate the specific bioactive components and unlock the therapeutic potential of these isolates in medical and related fields.