Aquaponics promotes sustainable Limnospira platensis cultivation via enhanced nutrient stability, antioxidant enrichment, and phytohormonal adaptation

This study compared the growth of Limnospira platensis in a conventional fertilizer-based system and an integrated aquaponics system over 30 days. The conventional system produced more biomass (2.12 g L⁻1) but showed nutrient instability and salt buildup. The aquaponics system yielded slightly less biomass (1.62 g L⁻1) but maintained more stable conditions, with near-neutral pH, steady conductivity, and higher dissolved oxygen (7.6–8.7 mg L⁻1). It also removed nutrients more effectively, reducing ammonium by 54–61% and nitrate by 32–55%. Biochemically, aquaponic biomass had slightly less protein (53.6% vs. 60.3%) and similar lipid content (9.85% vs. 10.0%), but was richer in antioxidants, with 33% more total phenolics and a 19-fold increase in auxin. These results show that aquaponics can sustainably produce L. platensis with improved functional and antioxidant properties, even if the overall biomass yield is lower.