Screening of multifunctional enzyme activity of fungi derived freshwater environment

Fungi, functioning as primary decomposers in freshwater ecosystems, possess complex metabolic mechanisms for organic matter, making them highly valuable as industrial enzyme resources. This study aimed to systematically screen 127 fungal strains isolated from freshwater environments in Korea for five highly demanded hydrolytic enzyme activities to identify superior strains with multi-substrate degradation capabilities. The enzymatic activity of each strain was quantitatively evaluated by measuring the diameter of the clear zone formed on agar plates supplemented with specific substrates. The screening results revealed that glycosidase activity had the highest prevalence, observed in 96.1% of the total isolates. This was followed by xylanase at 36.2%, protease at 33.1%, amylase at 29.1%, and cellulase at 18.9%. Strains exhibiting multifunctional activity across all five enzyme categories were extremely rare. Ultimately, three strains, FBCC-F4856, FBCC-F5657, FBCC-F5903 demonstrating all five enzymatic activities were selected. Among them, FBCC-F4856 exhibited robust glycosidase activity, while FBCC-F5657 recorded excellent degradation capabilities in xylanase and glycosidase. FBCC-F5903 also displayed comprehensive activity across all five enzymes, confirming its potential as a promising resource for establishing multi-enzyme systems. These findings demonstrate that freshwater-derived fungi are versatile biomaterials with complex enzymatic metabolic capabilities. With further research, the selected strains are expected to be utilized as valuable biological resources for various industrial applications.