Marine and freshwater Nannochloropsis for the bioremediation of brewery wastewater, CO2 capture, and CO-production of omega-3 lipids

This study explores Nannochloropsis for brewery wastewater (BWW) bioremediation, highlighting mixotrophic maltose assimilation and hyposaline adaptation. N. oceanica , N. gaditana , and N. limnetica grew successfully in filtered, undiluted BWW without salinity , nutrient, or pH adjustments, achieving a competitive final biomass concentrations (0.95 ± 0.03–1.04 ± 0.02 g L −1 ) to T. obliquus and C. vulgaris and complete removal of phosphate, nitrate, and ammonium (95–100 %). Salinity adjustment enhanced maltose assimilation (84 %), while nitrogen supplementation corrected N:P imbalance and increased biomass production to 1.40 ± 0.10 g L −1 . Nannochloropsis displayed mixotrophic pathways for simultaneous carbon sequestration (0.7–1.3 g CO₂ L −1 BWW) and organic‑carbon utilisation and removed >79 % COD through maltose assimilation. Semi-continuous cultivation reduced treatment time from 10 days (batch) to 2 days and improved COD reduction (up to 84 %). Nannochloropsis exhibited high fatty acid (34.4–36.3 % dw), ω-3 PUFAs (22.9 wt% of TFA), and chlorophyll (2.4 % dw) content, supporting food and fuel applications in line with net-zero goals.