Influences of Ferric Concentration on Growth and Fatty Acid Composition in Phaeodactylum tricornutum (Bacillariophyceae)

In order to study the effects of Fe concentration on growth and fatty acid composition in microalgae, a marine diatom, 3+ Phaeodactylum tricornutum, was cultured in batch with varied Fe concentrations. Its growth and fatty acid composition were 3+ examined. The results showed that P. tricornutum showed poor growth and the specific growth rate was 0.40/d in the medium with 0.5μmol/L Fe3+. However, the fatty acids of C and C18:3(n-6) accounted for highest percentages of total fatty acids, and 18:2(n-6) C20:5(n-3)(eicosapentaenoic acid, EPA) occupied lowest proportion. Fe 3+ overdose (24.5μmol/L) inhibited the algal growth, but the proportions of EPA and polyunsaturated fatty acids (PUFAs) in total fatty acids achieved the highest maximum. Lower EPA and PUFAs contents based on dry mass of P. tricornutum were associated with higher Fe3+ levels.