The saline wastewater (brine) generated by the tuna canning industry was used as a culture medium to grow non-photosynthetic marine microalgae. The bioprocess yielded 8.5 g/L of a nitrogen-enriched biomass (7.5% total N) in only three days. Microorganisms was able to remove more than 90% of organic nitrogen (amino acids and proteins) present in the brine.

The brine generated in the fish processing industry contains high concentrations of organic matter. To meet environmental legislation, brines require to be treated prior to disposal. High salinity and suspended solids are the major challenge for their management. Biological treatment of these brines using salt-tolerant microalgae is considered a sustainable and costeffective option compared to other currently available technologies. The major advantages of this approach are:
• Effective removal of organic matter and improved quality of effluent (Bioremediation)
• Nutrient capture and recycling in algal biomass with commercial interest (Circular Bioeconomy). The microorganism used is naturally present in coastal ecosystems and has a well-recognized market value as DHA source with a wide range of emerging applications.
• Enhanced productivity of algal culture (in terms of protein production) and costreduction of the culture process: saving water and nutrients (Advantage for the algal industry)
• Potential value of algal biomass as novel bio-based fertilizer which would drive nutrients to crop production (Emergent use of microalgal biomass)

Fig 1: Diagram that show the biological treatment of brines from fish canning industry using microalgae with potential value for agriculture use.
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Authors: Mirian Pinto Tobalina, Iratxe Urreta, Sonia Suarez, Susana Virgel, Itziar Orozco- Neiker
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