English
This study aimed to isolate fungi from various freshwater environments in Korea and to explore new or unrecorded species, while also evaluating their potential industrial applications. Freshwater samples were collected from rivers, lakes, and associated soils, as well as from the surfaces of aquatic organisms. From these samples, hundreds of fungal isolates were obtained, and through morphological characterization combined with molecular analyses, a total of 100 representative strains were selected for further study. These strains were subsequently subjected to functional screening, focusing on enzymatic activities, metabolite production, and antagonistic effects against microorganisms with an emphasis on traits of industrial importance.
Enzymatic activity assays targeted five groups of enzymes: amylase, cellulase, protease, xylanase, and glycosidase. Several isolates exhibited multiple enzyme activities, suggesting strong potential for industrial application. In particular, strains showing notable amylase and protease activities are promising for use in food, feed, and pharmaceutical industries. Furthermore, strains with high cellulase and xylanase activities were identified, highlighting their applicability in bioenergy production and eco-friendly material processing.
Phosphate solubilization assays revealed that certain strains were capable of effectively dissolving insoluble phosphate compounds, suggesting possible application in the development of biofertilizers. In addition, siderophore production was observed in multiple isolates, with some strains displaying robust secretion under iron-limited conditions. These properties indicate potential applications as plant growth-promoting microorganisms (PGPMs) as well as in environmental biotechnology, such as metal absorption and bioremediation.
Antagonistic activity assays demonstrated that several strains inhibited pathogenic bacteria, while others exhibited strong antifungal activity against phytopathogenic fungi. These results imply potential uses in the development of antibiotic alternatives, plant protectants, and functional biomaterials. Strains with multifunctional properties were identified as promising candidates for further in-depth studies.
Molecular phylogenetic analyses were performed to confirm the taxonomic positions of the selected isolates. Among them, strains F3799, F3814, and F3778 were identified as unrecorded species in Korea. Their unique morphological features and ITS rDNA sequence divergence distinguished them from known species, confirming their novelty and scientific value. Importantly, these newly reported species also exhibited significant industrially relevant traits.
In summary, this study successfully isolated and characterized fungal strains from Korean freshwater ecosystems, an environment that has been relatively underexplored in mycological research. By performing a comprehensive functional evaluation of 100 strains, we identified multiple isolates with high industrial potential. The discovery of the unrecorded species F3799, F3814, and F3778 not only expands the known fungal biodiversity of Korea but also provides valuable starting points for industrial biotechnology. Future work will focus on the purification and optimization of useful enzymes, discovery of novel metabolites, and validation of plant growth promotion and pathogen suppression activities. These findings underscore the richness of freshwater ecosystems as reservoirs of microbial resources and offer essential baseline data for the exploration and sustainable utilization of fungal biodiversity in Korea.
