*Correspondence: saharwefy@yahoo.com (Received: November 12, 2020; accepted: December 28, 2020) Citaton: Hamed MM, Abdrabo MAA, Fahmy NM, et al. Distributon and Characterizaton of Actnomycetes in Mangrove Habitats (Red Sea, Egypt) with Special Emphasis on Streptomyces mutabilis M3MT483919. J Pure Appl Microbiol. 2021;15(1):246-261. doi: 10.22207/JPAM.15.1.19 © The Author(s) 2021. Open Access. This artcle is distributed under the terms of the Creatve Commons Atributon 4.0 Internatonal License which permits unrestricted use, sharing, distributon, and reproducton in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creatve Commons license, and indicate if changes were made. Hamed et al. | J Pure Appl Microbiol | 15(1):246-261 | March 2021 Artcle 6766 | htps://doi.org/10.22207/JPAM.15.1.19 Print ISSN: 0973-7510; E-ISSN: 2581-690X ReseARCh ARtiCle OPeN ACCess www.microbiologyjournal.org 246 Journal of Pure and Applied Microbiology Distributon and Characterizaton of Actnomycetes in Mangrove Habitats (Red Sea, Egypt) with Special Emphasis on Streptomyces mutabilis M3Mt483919 Moaz M. Hamed, Mohamed A.A. Abdrabo, Nayer M. Fahmy, Lamis S. Abdelfatah, Mahmoud S. Kelany, Hala H. Abd-El latf, Gehan M. Abou El ela, Hanan M Abd-Elnaby and Sahar W.M. Hassan* Marine Microbiology Laboratory, Marine Environmental Division, Natonal Insttute of Oceanography and Fisheries, Egypt. Abstract Ten sediment samples were gathered from several geographical locatons around mangrove habitat, Red Sea coast, Egypt, during summer 2019. Actnobacteria are widespread in most mangrove soil samples. The average actnomycetes counts in sediment samples were ranged from 4 to 15 CFUg -1 , also physico-chemical characters for soil samples were determined. Statstcal analysis was applied to assess if the geographical locaton and physico-chemical characters infuenced the communites of actnomycetes. A total of 10 actnomycetes were isolated and characterized physiologically and biochemically. The antmicrobial actvites of diferent actnomycetes isolates were assessed. Isolate M3 was chosen as the most promising isolate with broad antagonistc actvity against Bacillus subtlis AtCC 6633, Escherichia coli ATCC 19404, Staphylococcus aureus ATCC6538, Pseudomonas aeruginosa AtCC 9027, and Candida albicans ATCC 10231 with inhibiton zones ranged from 12.0 ± 0.9 to 20.0 ± 1.9 mm. Genotypic characterizaton of isolate M3 was made using 16S rDNA sequence analysis and identfed as Streptomyces mutabilis M3 with accession number MT483919. This strain exhibited antcancer actvity against breast cancer cell line (Mcf7), liver cancer cell line (HepG2) and colon cancer cell line (HCT116) and the IC50 values were 324.77, 333.71 and 354.46, respectvely. Streptomyces mutabilis M3 Mt483919 had high bio-focculatng actvity for seawater treatment, and the recovery of the samples ranged between 71.97 and 76.05%. The crude extract of Streptomyces mutabilis MT483919 M3 was analyzed by Fourier transform infrared spectrum (FT-IR) and Gas chromatography-mass spectrometry (GC-MS). Keywords: Mangrove Habitats, Streptomyces mutabilis, M3