Abstract

This study examines the production of polyunsaturated fatty acids (PUFAs) and carotenoids in Labyrinthulomycetes isolated along a thermal gradient on the Chilean coast. Phylogenetic analysis revealed clades corresponding to Oblongichytrium, Schizochytrium, and Thraustochytrium aggregatum. Strains of Oblongichytrium sp. from colder, higher pH sites (9°C, pH 8.64) produced up to 34 times more DHA in laboratory conditions than those from warmer, lower pH areas (13°C, pH 7.30), suggesting an influence of native environmental conditions on biosynthetic capacity. In contrast, DHA production by Schizochytrium sp. and T. aggregatum was limited to specific isolates, without a clear latitudinal pattern. Polyunsaturated fatty acids were detected in all strains, although no relationship with environmental variables was found. All strains produced astaxanthin, while ?-carotene was detected in some, with no consistent pattern; canthaxanthin was absent. The results highlight the high biotechnological potential of Oblongichytrium strains from colder, alkaline coastal environments, emphasizing the importance of exploring diverse natural habitats for organisms with valuable lipid production profiles. This study supports the value of targeted bioprospecting to identify strains with promising applications in lipid-based industries. © 2025 International Society of Protistologists.