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Omega-3 poly-unsaturated fatty acids from microalgae

Identification

Key words omega-3 poly-unsaturated fatty acid, microalgae, health benefit, supplementation, fish oil, extraction
Latest version 2011/10/05
Completed by KU Leuven LFT

How does it work?

Primary objective Production of long-chain poly-unsaturated omega-3 fatty acids (eicosapentaenoic and docosahexaenoic acid) through autotrophic cultivation and harvesting of microalgae, followed by lipid extraction and processing with the aim of supplement preparation.
Working principle Microalgal biomass is a rich source of omega-3 poly-unsaturated fatty acids (omega-3-PUFA), of major interest to the food industry, as well as for the nutraceutical and pharmaceutical sector, because of their health benefits (1,2). After all, in many Western countries, the current average intake of omega-3-PUFA is below the recommended level, which raises interest in food enrichment or dietary supplementation with omega-3-PUFA.

Currently, the main commercial source of omega-3-PUFA is fish oil. However, several problems are associated with these oils: unpleasant odor, contamination with heavy metals, as well as increasingly stringent regulation of fisheries. The use of selected microalgae as a source of omega-3-PUFA can help to overcome these limitations.

Autotrophic omega-3-PUFA-rich microalgae (e.g. Phaeodactylum sp., Nannochloropsis sp., Isochrysis sp., Porphyridium sp., ...) can be grown in open ponds, but are usually cultured in closed photobioreactors. Species are selected based on their omega-3-PUFA synthesis potential and the ease and reproducibility with which they can be cultured at a high productivity. Culturing conditions, including air and light, can be fine-tuned in order to optimize the omega-3-PUFA formation during photosynthesis (depending on the type of omega-3-PUFA aimed at and the organism worked with). Microalgae are typically harvested through centrifugation, although other techniques can be used as well (e.g. membrane filtration, flocculation, ...). Today, the oil is mostly extracted with hexane or other solvents in combination with mechanical cell disruption, such as bead milling. Alternatively, pulsed electric field processing, ultrasonic energy, microwaves, enzymes or supercritical fluid extraction can be applied, although not yet at an industrial scale (6). Omega-3-PUFA are further concentrated (e.g. using urea fractionation) and purified (e.g. HPLC) from this extract (3).

Images
Additional effects In addition to use of single-cell oil, whole biomass can be used as a source of omega-3-PUFA in food or feed.
Important process parameters culture conditions (light/dark, temperature, oxygen concentration, nutrients present, batch/continuous, renewal of organisms, ...) and extraction technique. Low temperatures and high CO2 concentration tend to augment the Omega-3-PUFA production.
Important product parameters

What can it be used for?

Products Functional foods, infant nutrition, neutraceuticals, ...

Application of microalgae has been demonstated in functional biscuits (4)

Operations Centrifugation, flocculation, filtration, extraction, purification, , ….
Solutions for short comings This technology replaces traditional oils rich in omega-3-PUFA, such as fish oil, that is characterized by unpleasant odor, contamination with heavy metals, as well as increasingly stringent regulation of fisheries.

What can it NOT be used for?

Products Products that need to be stored in aerobic conditions.
Operations Heating, oxidation
Other limitations Currently, two main drawbacks can be identified:
  1. Economical aspects. Microalgae are currently rather expensive. Prices are expected to decrease as cheaper culturing and harvesting techniques are being developed.
  2. Few microalgae species are currently approved by EFSA.
Risks or hazards Although some microalgae are known to produce toxins, careful selection of species will certainly overcome this hazard.

Implementation

Maturity Currently, singe-cell oils from heterotrophically cultivated microalgae are on the market. For photoautotrophic microalgae, scale-up of cultivation is possible, however currently rather expensive.
Modularity /Implementation This is a completely different production process as compared to production of fish oil. Cultivation and harvesting processes need to be implemented. Extraction and further downstream processing conditions need to be optimized.
Consumer aspects Consumer acceptance is not expected to be a hurdle.
Legal aspects Few microalgae species are currently approved by EFSA.
Environmental aspects Use of microalgae as a source of omega-3-PUFA can be beneficial to the environment, as this can help to overcome problems of overfishing.

Further Information

Institutes KU Leuven KULAK Aquatic biology, Institut für Getreideverarbeitung, UAL chemical engineering
Companies Ingrepro, SBAE-industries
References 1. Cardozo, Guaratini, Barros, Falcao, Tonon, Lopes, CamposTorres, Souza, Colepicolo, Pinto (2007). Metabolites from algae with economical impact. Comparative biochemistry and physiology Part C 146, 60-78.

2. Chacon-Lee,Gonzalez-Marino (2010). Microalgae for Healthy Foods: Possibilities and Challenges. Comprehensive Reviews in Food Science and Food Safety 9, 655-675.

3. Robles Medina, Molina Grima, Giménez Giménez, Ibanez Gonzalez (1998). Downstream processing of algal polyunsaturated fatty acids. Biotechnology advances 16(3), 517-80.

4. Gouveia L, Coutinho C, Mendonca E et al. (2008) Functional biscuits with PUFA-omega 3 from Isochrysis galbana. Journal of the Science of Food and Agriculture 88, 891-896.

5. Mercer, P. and Armenta, R.E. (2011) Developments in oil extraction form microalgae. Eur.J. Lipid Sci. Technol. 113, 539-547.



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Created by LiesbethV on 11 October 2011, at 08:45