Manipulating antioxidant content in macroalgae in intensive land-based cultivation systems for functional food applications

The recently domesticated marine macroalga Derbesia tenuissima is suitable for intensive land-based production and is a promising species for functional food applications and bioproducts as it is rich in bioactive components and has high biomass productivity. For the first time, we quantified the effects of inducing different degrees of light stress by managing culture conditions (as biomass density) in land-based 2000 L cultures, on the total phenolic content, antioxidant capacity (DPPH, FRAP, ABTS), and biomass and antioxidant productivity of Derbesia. We demonstrate that it is possible to manipulate the antioxidant content of Derbesia by managing culture conditions, with up to 88% higher antioxidant capacity in biomass stocked at 0.5 g L−1 than when stocked and maintained at 2 g L−1 , or stocked at 2 g L−1 and harvested weekly. Antioxidant productivity of tank-cultured D. tenuissima is high – up to 680 μmol gallic acid equivalents m−2 day−1 – and can be maximised by selecting low initial stocking densities without compromising productivity per unit land area