Vienna Ai Marie V. Dela Cerna, Paul John L. Geraldino
Negros Oriental in the Philippines provides a rich diversity of geothermal habitats. Despite the abundance, there are only a few published thermophile studies in the area. This study aimed to isolate thermophilic cyanobacteria from a hot spring in Negros Oriental and use morphological and molecular features for characterization and identification. Six filamentous, homocystous cyanobacteria designated as CV1, CV2, CV3, CV4, CV5, and CV6 were successfully isolated and cultured. Morphological characterization showed light green to blue-green sheathed trichomes that form an interwoven pattern similar to the recently identified cyanobacterium, Alkalinema. Partial 16S rRNA gene sequences revealed 98.58% identity of the strains with Alkalinema pantanalense DCHY213, and phylogenetic analysis placed them under the family Leptolyngbyaceae – hence forming a separate cluster from other A. pantanalense strains. The differences in ecotype and morphotype, as well as the distinct clustering in the phylogenetic tree of the Negros Oriental strains, imply the possibility of belonging to a different species. Amylase activity was detected in all strains except CV4, hence implying their potential for bioactive metabolite studies. These results highlight the importance of untapped extreme environments in the country for the discovery of novel or recently identified microorganisms that have taxonomical, ecological, and biotechnological applications. © 2024, Department of Science and Technology. All rights reserved.
Institute of Biology, College of Science, University of the Philippines Diliman, Quezon City, 1101, Philippines; Department of Biology, School of Arts and Sciences, University of San Carlos, Cebu City, 6000, Philippines
