The Philippines is known for its astounding biodiversity. Numerous species of flora and fauna are known to inhabit the Philippine marine and terrestrial domains. True to its highly diverse nature, the country hosts more than 50 percent of the total mangrove species around the world. Mangrove extracts are known sources of antifungal, antiviral, anti-cancer and anti-diabetic compounds. Furthermore, they may pose a great potential in hosting a multitude of microorganisms with promising therapeutic capabilities. Prior studies have shown that the plethora of benefits mangrove possess can be attributed to the microorgranisms of its microbiome, or known as the endophytes. This study isolated bacterial endophytes from a mangrove tree, which was later on identified as Rhizophoramucronata, from a mangrove forest in Combado, Maasin City, Southern Leyte. A total of 15 colonies were primarily selected and isolated, which were narrowed down to 10 morphologically distinct isolates. These isolates were characterized through polyphasic identification which included the morphological characterization and molecular techniques. For the morphology, the isolates were characterized through colony morphology and microscopic observation of the Gram’s stain. For the molecular techniques, the DNA of the isolates were isolated and the 16s rRNA gene was amplified. Each of the morphospecies was sent to Macrogen in South Korea for DNA sequencing. The sequences received were then analyzed and made into phylogenetic trees to show the relationship between these bacterial species and other species of bacteria. A total of eight bacterial endophytes were identified. Of the eight, three belonged to the genus Bacillus, three to the genus Staphylococcus, and two to the genus Lysinibacillus. Results show that the bacterial endophytes isolated from Rhizophoramucronata were Lysinibacillus fusiformis, Staphylococcus haemolyticus, Staphylococcus epidermidis, Bacillus aryabhattai, Bacillus licheniformis, Bacillus amyloliquefaciens and Lysinibacillusboronitolerans.

Keywords : 16s rRNA gene, bacterial endophyte, DNA barcoding, mangrove, molecular identification, phylogenetic tree, polyphasicidentification, Rhizophoramucronata