Biomass, Lipid and Fatty Acid Production in Large-Scale Cultures of the Marine Macroalga Derbesia tenuissima (Chlorophyta)

Biomass productivity was quantified for the marine macroalga Derbesia tenuissima cultivated outdoors at seven stocking densities from 0.25 to 8 g L−1 for 5 weeks. Total lipids and fatty acid quantity and quality was measured from samples that were freeze-dried, dried by oven (75 °C), food dehydrator (60 °C), or outdoor in the sun (40 °C) or shade (38 °C). Stocking densities of 0.25 to 2 g L−1 yielded the highest biomass productivities (>20 g dry weight m−2 day−1) with no effect on total lipid quantity (11 %), or fatty acid quantity (5.3 %) or quality at any density tested. However, there was an interactive effect of stocking density and drying technique, with a decrease of up to 40 % in polyunsaturated fatty acids in sun-dried compared to freeze-dried biomass. Notably, while fatty acid and biomass productivity may be inseparable in macroalgae, cultivation conditions have a sig- nificant carryover effect in the post-harvest delivery of high- quality bio-oils.