Effects of iron on the growth, chlorophyll a , total lipids, and fatty acids of Chaetoceros lorenzianus

Polyunsaturated fatty acid (PUFA) and eicosapentaenoic acid (EPA) are essential for the health of aquatic organisms and human beings. In order to optimize the culture conditions of the diatom Chaetoceros lorenzianus , effects of different iron sources (FeC 6 H 5 O 7 , FeCl 3 , FeSO 4 ) and different iron concentrations (0.10, 0.25, 0.50, 0.75, 1.00, 1.25 mg L −1 ) on C. lorenzianus were studied. The results showed that different iron sources and different iron concentrations had significant effects on the growth, chlorophyll a , total lipid and fatty acids of C. lorenzianus . The growth rate (0.47 day −1 ), chlorophyll a (510.57 μg L −1 ), total lipids (11.82%), and n-3 PUFA (EPA and DHA) (21.20%) contents were significantly higher in the FeCl 3 group when compared to FeSO 4 and FeC 6 H 5 O 7 groups. The optimum concentration of FeCl 3 for the growth and synthesis of chlorophyll a was 0.75–1.00 mg L −1 and the optimum concentration for lipid accumulation was 0.25 mg L −1 . The secondary culture method can be used in large-scale culture, that is, the initial culture is performed under the optimal iron concentration (0.75 mg L −1 FeCl 3 ) for obtaining higher biomass. Then, the secondary culture would be performed under a low iron concentration (0.25 mg L −1 FeCl 3 ), obtaining high total lipids in algal cells. These findings make tangible contributions to culture C. lorenzianus for potential commercial production of PUFA and EPA.