Fatty acid composition of several wild microalgae and cyanobacteria, with a focus on eicosapentaenoic, docosahexaenoic and α-linolenic acids for eventual dietary uses A. Catarina Guedes a, b , Helena M. Amaro b , Catarina R. Barbosa a , Ricardo D. Pereira a , F. Xavier Malcata b, c, ⁎ a CBQF/Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, P-4200-072 Porto, Portugal b CIIMAR — Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas no. 289, P-4050-123 Porto, Portugal c ISMAI — Instituto Superior da Maia, Avenida Carlos Oliveira Campos, Castelo da Maia, P-4475-690 Avioso S. Pedro, Portugal abstract article info Article history: Received 19 February 2011 Accepted 25 May 2011 Keywords: Lipid profile EPA DHA ALA PUFA Microorganism A total of 13 species of microalgae and 14 strains of cyanobacteria, collected directly in the Portuguese coast and lagoons, were characterized for their fatty acid contents, focusing on two with a market potential — i.e. eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); and another already with alternative (yet somehow more expensive) natural sources — i.e. α-linolenic (ALA) acid. The purpose of this work was their eventual inclusion as additives in food or feed. ALA was the most abundant PUFA in Nannochloropsis sp. (0.616 ± 0.081 mg FA .L culture -1 .d -1 ), and EPA in Phaeodactylum tricornutum (0.148± 0.013 mg FA .L culture -1 .d -1 ); Pavlova lutheri was particularly rich in EPA (0.290± 0.005 mg FA .L culture -1 .d -1 ) and DHA (0.140±0.037 mg FA .L culture -1 .d -1 ). Despite several previous reports on similar topics and encompassing some of our microalgal species, the wild nature of our strains accounts for the novelty of this work — in addition to the characterization of a few wild cyanobacteria. Eustigmatophyceae class was the best producer of ALA, while Prymnesiophyceae was the best for EPA and ALA. Nodularia harveyana exhibited the highest ALA level (0.611±0.022 mg FA .L culture -1 .d -1 ) and Gloeothece sp. was highest in EPA (0.030±0.004 mg FA .L culture -1 .d -1 ). © 2011 Elsevier Ltd. All rights reserved. 1. Introduction Microalgae and cyanobacteria encompass microorganisms that obtain energy from light — yet they represent extremes in lipid chemistry, as eukaryotic and prokaryotic models, respectively. Both can produce valuable metabolites, e.g. antimicrobials, antioxidants and polyunsaturated fatty acids (PUFAs), and have often been considered as vectors for commercial manufacture of oils and fats as alternative to higher plant and animal sources; advantages over fish oils include lack of unpleasant odor, reduced risk of chemical contamination and ease of refining. PUFAs are found in animals, plants, fungi, microalgae and bacteria — in which they are a part (as such, or included as moieties in more complex compounds) of membranes or storage organelles, typically in the form of glycolipids, phospholipids, sphingolipids and lipoproteins (Thelen & Ohlrogge, 2002). Interest therein has emerged in recent years, owing to their potential therapeutic uses, in addition to their nutritional applications derived from physiological roles in actual cells; the importance of a balanced PUFA intake has accordingly been recognized by the various health organizations throughout the world, and several food manufacturers have built processing facilities and labeled claims following their recommendations. Current food sources of omega-3 (ω3) and omega-6 (ω6) PUFAs are fish and shellfish, flaxseed (linseed), hemp oil, soya oil, canola (rapeseed) oil, chia seeds, pumpkin seeds, sunflower seeds, leafy vegetables and walnuts; however, the major sources of EPA and DHA, on a worldwide basis, are still marine fish. Microalgae and cyanobacteria exhibit competitive advantages as sources of PUFAs, because fish have typically lower contents (on a mass basis), are subject to seasonal variations in fatty acid profile, and may be significantly contaminated with heavy metals owing to pollution throughout the feed chain (Guil-Guerrero, Belarbi, & Rebolloso-Fuentes, 2001); furthermore, they have a limited capacity for synthesis of PUFA — so most of them are simply accumulated from their microalgal diet. This latter realization has turned microalgae into one of the most important feed items in aquaculture, as they are de novo producers of PUFAs and can accumulate them to relatively high levels (Tonon, Harvey, Qing, Larson, & Graham, 2002) — which have, in turn, been shown to trigger particularly high rates of growth of aquacultured fish. Food Research International 44 (2011) 2721–2729 Abbreviations: AA, arachidonic acid C20:4(n-6) Δ5,8,11,14 ; ALA, α-linolenic acid C18:3 (n-3) Δ9,12,15 ; DGLA, dihomo-γ-linolenic acid C20:3(n-6) Δ8,11,14 ; DHA, docosahexaenoic acid C22:6(n-3) Δ4,7,10,13,16,19 ; DPA, docosapentaenoic acid C22:5(n-3) Δ7,10,13,16,19 or C22:5(n-6) Δ4,7,10,13,16 ; EDA, eicosadienoic acid C20:2(n-6) Δ11,14 ; EPA, eicosapentaenoic acid C20:5(n-3) Δ5,8,11,14,17 ; ETA, eicosatetraenoic acid C20:4(n-3) Δ8,11,14,17 ; ETrA, eicosatrienoic acid C20:3(n-3) Δ11,14,17 ; GLA, γ-linolenic acid C18:3(n-6) Δ6,9,12 ; LA, linoleic acid C18:2(n-6) Δ9,12 ; LC-PUFA, long-chain (with at least 20 carbon atoms) polyunsaturated fatty acid; PUFA, polyunsaturated fatty acid; SDA, stearidonic acid C18:4(n-3) Δ6,9,12,15 . ⁎ Corresponding author at: ISMAI – Instituto Superior da Maia, Avenida Carlos Oliveira Campos, Castelo da Maia, P-4475-690 Avioso S. Pedro, Portugal. Tel.: + 351 968 017 411; fax: +351 229 825 331. E-mail address: fmalcata@ismai.pt (F.X. Malcata). 0963-9969/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodres.2011.05.020 Contents lists available at ScienceDirect Food Research International journal homepage: www.elsevier.com/locate/foodres