Antioxidant and Antimicrobial Activity of Microalgae of the Filinskaya Bay (Baltic Sea)

Microalgae are rich in proteins, carbohydrates, lipids, polyunsaturated fatty acids, vitamins, pigments, enzymes, and other biologically active substances. This research aimed to study the composition and antioxidant and antimicrobial activity of proteins, lipids, and carbohydrates of microalgae found in the Filinskaya Bay of the Kaliningrad region. The chemical composition of <i>Scenedesmus intermedius</i> and <i>Scenedesmus obliquus</i> microalgae biomass was studied. Ultrasound was used to isolate valuable components of microalgae. It was found that microalgae are rich in protein and contain lipids and reducing sugars. To confirm the accuracy of the determination, the protein content was measured using two methods (Kjeldahl and Bradford). Protein content in <i>S. intermedius</i> and <i>S. obliquus</i> microalgae samples did not differ significantly when measured using different methods. Protein extraction by the Kjeldahl method was found to be 63.27% for <i>S. intermedius</i> microalgae samples and 60.11% for <i>S. obliquus</i> microalgae samples. Protein content in <i>S. intermedius</i> samples was 63.46%, compared to 60.07% in <i>S. obliquus</i> samples, as determined by the Bradford method. Lipids were 8.0–8.2 times less abundant than protein in both types of microalgae samples. It was determined that the content of reducing sugars in the samples of the studied microalgae was 5.9 times less than the protein content. The presence of biological activity (antioxidant) in proteins and lipids obtained from biomass samples of the studied microscopic algae was established, which opens up some possibilities for their application in the food, chemical, and pharmaceutical industries (as enzymes, hormones, vitamins, growth substances, antibiotics, and other biologically active compounds).