Bioremediation of seafood processing wastewater by microalgae: Nutrient removal, and biomass, lipid and protein enhancement

Demand for surimi-based products has surged due to their convenience, and high protein content. However, the production process generates a large amount of nutrient-rich wastewater (SWW), which is beneficial to microalgae. Hence, the purpose of this study was to examine how six marine microalgae species grew at varying concentrations of SWW and extra nutrients (molasses-M, sodium nitrate-SN, ferric chloride-FC). The cultivation was conducted for ten days in a controlled environment, including aeration, light exposure, and temperature (22-27°C). Results showed that a 10% SWW promoted maximum biomass and nutrient removal, with Nannochloropsis oculata achieving 5.15 ± 1.27 g/L biomass, 80% NO3-, 100% PO43-, and 48% COD reduction. Under additional nutrient supplementations, microalgae achieved higher biomass, reaching 5.79 ± 0.24 g/L, with complete PO43- and NO3- removal, and COD reduction (71.54% − M : FC and 80.32% − M : SN). Additionally, the protein content was considerably raised by both SN and FC (32.41 ± 2.21% and 27.15 ± 0.88%), whereas the lipid content was decreased by SN (20.05 ± 1.36%) and increased by FC (27.38 ± 1.17%). This research highlights the potential of SWW for marine microalgae growth and the impact of nutrient supplementation, offering valuable insights in the field of bioresource technology.