Table of Contents

ABSTRACT

Long-chain polyunsaturated fatty acids (LC-PUFAs), such as the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) provide significant health benefits. LC-PUFAs can be recovered from many marine organisms, transgenic plants, fungi and many microorganisms but the largest amount is currently extracted from fish. However, global fish stocks are declining and more sustainable sources of LC-PUFAs have to be established. As primary producers of the aquatic food chain, many marine microalgae produce considerable amounts of PUFAs, in particular EPA and DHA that could form the basis for sustainable industrial production of LC-PUFAs. Heterotrophic microalgae are already being used commercially, in particular for DHA production as a food supplement, however production has high setup and operational costs. Hence, autotrophic production systems may allow further expansion of the use of microalgae as LC-PUFA biofactories. Direct comparison of different microalgal strains have shown promising candidates for future commercial production. Here, we analyse various cultivation conditions for EPA production in four subtropical microalgal species. The results of others and our own data reported here, demonstrate that microalgal omega-3 production can be stimulated under certain conditions and optimised to achieve higher yields. We discuss how LC-PUFA production in autotrophically-grown microalgae could be best optimised and possibly explored under conditions of large-scale outdoor cultivation.

Keywords: cultivation, microalgae, omega-3 fatty acid, salinity