Cultivation of a native microalgae–bacterial consortium in seafood processing wastewater primarily from skipjack tuna

Seafood processing wastewater, rich in organic carbon and nutrients, represents a potential low-cost medium for algal biomass cultivation. Here, we evaluated the growth performance of a naturally adapted microalgae-bacterial consortium isolated from a seafood processing facility primarily handling skipjack tuna. The consortium was cultured directly in raw wastewater without nutrient supplementation. Within 9 days, chlorophyll concentration increased fivefold and total suspended solids nearly doubled, indicating substantial biomass accumulation. Dissolved organic carbon and phosphate declined by 85% and 68%, respectively, indicating nutrient assimilation by the microbial community. The culture also showed a pH increase, consistent with active photosynthetic carbon uptake. Ammonium transiently accumulated before declining during algal growth, while nitrate remained low and nitrite undetectable, indicating a nitrogen cycle dominated by ammonium with minimal oxidation. These results demonstrate the feasibility of valorizing seafood wastewater for microalgal biomass production and provide a basis for sustainable, resource-oriented applications of industrial effluents.