Biochemical Screening of the New Strain Dolichospermum solitarium (Cyanobacteria) for Phytoremediation and Biotechnology

This work described a novel freshwater strain of Cyanobacteria, Dolichospermum solitarium MAC–C17 from the Zaporozhye region in the south of European Russia and characterised its growth and biochemical parameters. The strain demonstrated high biomass, lipid, and protein productivity, comparable to the best-known data for high-productivity cyanobacteria. The highest protein content (383.76 mg g−1 dry weight) was in the exponential growth phase. In contrast, the highest content of lipids, vitamin E (α-tocopherol) and vitamin A (retinol) was in the stationary phase (150.05 mg g−1, 45.58 µg g−1 and 31.61 µg g−1). The productivity of Dolichospermum solitarium MAC–C17 was 19.26 mg L−1 d−1 for lipids, 42.54 mg L−1 d−1 for protein, 4.06 µg L−1 d−1 for retinol, and 5.85 µg L−1 d−1 for α-tocopherol. A distinctive feature of the new strain was its high chlorophyll a content (4.87–6.12 mg g−1). The antioxidant defence system of Dolichospermum solitarium differed between the exponential and stationary growth phases. During the exponential growth phase, strain MAC–C17 exhibited high catalase activity. In contrast, the stationary phase was characterised by a distinct shift in its antioxidant profile, marked by a substantial increase in superoxide dismutase and glutathione peroxidase activities, a significant rise in retinol and α-tocopherol levels. These findings suggest that strain Dolichospermum solitarium MAC–C17 possessed considerable biotechnological potential. It demonstrated strong potential as a producer of high-value commercial compounds, a promising candidate for developing antioxidant formulations, and a valuable asset for applications that boost agricultural yields and advance phytoremediation technologies.