Manipulation of fatty acid and antioxidant profiles of the microalgae Schizochytrium sp. through flaxseed oil supplementation

Due largely to their unique and diverse metabolic profile, microalgae have embedded themselves in a plethora of commercial applications encompassing nutrition, cosmetics and biofuel production. The present research demonstrates the ability to improve the nutritional properties of Schizochytrium sp. through direct medium supplementation with flaxseed oil. Increasing supplemental concentrations, to a maximum of 1% v/v, reflected a 2.8-fold improvement in dry cell weight, yielding a maximum 17.1 ± 1.3 g/L. Cultures with higher biomass yields also demonstrated increased glucose utilisation, which may have influenced the final fatty acid profiles of each culture. At inclusion levels above 0.05%, total fatty acid amounts reduced in a near linear fashion, potentially in response to a glucose deficient environment. Supplementation of just 0.05% flaxseed oil resulted in the incorporation of exogenous C18 fatty acids into the algal biomass, as well as significantly increasing docosahexaenoic acid (DHA) titres to 100.3 ± 4 mg/g algae (p ≤ 0.05). At the same inclusion rate, the antioxidant capacity and phenolic content of algal biomass were significantly enhanced, particularly in the methanolic faction (p ≤ 0.001). The inclusion of essential linoleic and α-linolenic fatty acids with improved levels of DHA and enhanced antioxidant status demonstrate the suitability of medium supplementation to improve the nutritional value of microalgae.