Microalgal biofactories: a promising approach towards sustainable omega-3 fatty acid production

Microalgae offer potential for numerous commercial applications, including the production of w-3 polyunsaturated fatty acids (w-3 PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These valuable fatty acids are important for a variety of nutraceutical and pharmaceutical purposes, and this has led to increased consumption as food supplements. Currently, the main source of EPA and DHA is marine fish oil, which is inadequate and unattractive mostly because of taste, odor and stability problems, and unsustainable because it contributes to overfishing global fish stocks. There is a variety of alternative EPA and DHA sources such as bacteria, fungi, and plants that are currently being explored for commercial production.Fungi require organic carbon sources, plants need arable land, have longer growth times and have no enzymatic activity for producing long chain PUFA, unless genetically modified. Several microalgal species that are the primary EPA and DHA producers in the marine food chain, contain high level of specific PUFAs and can grow under a variety of autotrophic, mixotrophic and heterotrophic conditions, offer a valuable and sustainable alternative source of PUFAs that may help to meet the increasing demand for fish oil. This presentation outlines an introductory overview of PUFA-related health benefits in humans, describes PUFA occurrence in different microalgal species together with the most important growth parameters affecting fatty acid content and profile and depicts the major pathways of their biosynthesis in selected species of microalgae. Furthermore, the recent improvements in cultivation systems utilised for large-scale microalgae mass production are illustrated and the feasibility of cultivating selected microalgal strains as a potential source of EPA evaluated. The opportunities and bottlenecks of microalgal production and refinery are also discussed.