Abstract:Fucoxanthin is a kind of carotenoids that participates in the photosynthesis of marine algae and has multiple functions such as anti-oxidation, anti-cancer, anti-obesity and anti-diabetes, showing important applications value as the biological medicine and functional food. Marine diatom Phaeodactylum tricornutum has high content of fucoxanthin, which is considered as a new source of algae-based fucoxanthin besides brown seaweed. Aiming to improve the fucoxanthin production, P. tricornutum CCMP2561 was applied in this study to systematically evaluate the effects of organic carbon, nitrogen sources and their concentrations on the cell growth and fucoxanthin production under mixotrophic (photo fermentation) conditions. The optimal combination of carbon and nitrogen source was 0.10 mol/L of glycerol, 0.02 mol/L of total nitrogen mixed by tryptone and urea (1∶1). Under this optimal combination, the maximum biomass concentration, fucoxanthin content and yield were achieved at 3.94 g/L, 20.83 mg/g and 81.97 mg/L in P. tricornutum respectively, which were 3.15, 11.64, and 36.59 times to those before optimization under 2 000 lx of light intensity, 20 ℃ of culture temperature and 150 r/min of shaking speed. The optimal medium and approach for mixotrophic cultivation developed in this study could provide a newly practical technology for significant enhancement of fucoxanthin production in P. tricornutum.
