Waste and Biomass Valorization, 2025 (SCI-Expanded, Scopus)
Microalgae are photosynthetic organisms capable of producing a wide range of bio-products enriched with valuable bioactive compounds, including pigments, proteins, lipids, and fatty acid methyl esters (FAMEs). Among the various environmental factors influencing microalgal metabolism, salinity is a key stressor that can significantly affect both growth and biochemical composition. In this study, the effects of varying salinity levels on Chlorella vulgaris were investigated by culturing the strain in BG11 medium supplemented with NaCl at concentrations of 0 M, 0.03 M, 0.1 M, and 0.3 M. Growth, pigment content, total protein and lipid concentrations, and fatty acid profiles were evaluated. Results indicated that moderate salinity levels (0.03 M and 0.1 M NaCl) promoted increased cell growth and pigment accumulation, while higher salinity (0.3 M NaCl) enhanced lipid and FAME yields. A notable shift from saturated fatty acids (SFAs) to polyunsaturated fatty acids (PUFAs) was observed at elevated salinity, improving the nutritional value of C. vulgaris as a human food source. Furthermore, the reduction in cold filter plugging point (CFPP), observed especially in the 0.1 M and 0.3 M salinity groups, indicates an improvement in the low-temperature flow properties of biodiesel, which is a desirable trait for fuel performance compared to the control group. These findings offer valuable insights for developing sustainable and cost-effective microalgal cultivation strategies for applications in both the food and biofuel industries.