Lake-based aquatic ecosystems provide irreplaceable water resources for humans. Microbiomes of lake ecosystems are adequate resources for agriculture, industry and related sectors. Completing the CNMN with new strains of biotechnological interest is one of the tasks of the National Collection of Non-Pathogenic Microorganisms (CNMN). Numerous scientific papers have shown that aquatic microorganisms possess antimicrobial properties against a wide range of phytopathogens. Aquatic microorganisms (bacteria, fungi, actinobacteria, etc.) also produce hydrolytic enzymes, which degrade many compounds, thus contributing to the purification of aquatic environments. Based on the above, the purpose of the research was to study the activity of catalase and amylase in isolated strains from the Lake La Izvor and to supplement the CNMN with new strains potentially producing bioactive substances. The bacteria and mycelial fungi isolated from Lake La Izvor served as the object of study. Catalase activity and amylase activity were determined in 65 strains of bacteria and 95 strains of mycelial fungi isolated from the Lake La Izvor. Enzymatic activity was determined by express methods (amylase on starch agar media; catalase - application of H2O2 on the surface of colonies). Thus, in the testing of bacterial strains, from 65 strains at 30, a significant catalase activity was identified, and 22 strains showed a high amylase activity. Another 15 bacterial cultures showed significant amylase and catalase activity. Of 95 strains of mycelial fungi catalase activity was identified in 70 strains, more significant being recorded in 50 strains. Amylolytic activity showed 50 strains of mycelial fungi, of which in 20 strains this activity was significant. Thus, we can conclude that aquatic microorganisms represent a very high biotechnological potential.