Effective fucoxanthin production in the flagellate alga Poterioochromonas malhamensis by coupling heterotrophic high-cell-density fermentation with illumination.

The unicellular flagellate algae is a potential fucoxanthin-rich resource for sustainable and cost-effective fucoxanthin production. Light and nutrients are critical regulators for the accumulation of fucoxanthin in . In this study, the maximum fucoxanthin yield of 50.5 mg L and productivity of 6.31 mg L d were achieved by coupling high-cell-density fermentation with illumination. It was found that the combined use of organic and inorganic nitrogen (N) nutrition could improve the fucoxanthin yield as single inorganic or organic N had limitation to enhance cell growth and fucoxanthin accumulation. White light was the optimal light quality for fucoxanthin accumulation. Under white light and a moderate light intensity of 150 μmol m s, the highest biomass concentration and fucoxanthin content reached 32.9 g L and 1.56 mg g of dry cell weight (DCW), respectively. This is the first study on effective fucoxanthin production in by integrating illumination with high-cell-density fermentation, which paved the way for further development of as a potential source for commercial fucoxanthin production.