Microalgae and their potential in food and feed applications
Worldwide, there is an increasing interest in microalgae and cyanobacteria (a group of photosynthetic organisms that can easily survive on bare minimum requirement of light, carbon dioxide and water), for their potential as a source of nutrition. Algae biomass provides a variety of low-cost products for human and animal consumption, including cattle feed and aquaculture applications. Some microalgae strains are protein-rich, with valuable components such as antioxidants, polyunsaturated fatty acids (PUFAs) and triglycerides (lipids) that could be exploited for their nutritional value and nutraceutical components. Microalgae has also been recognised as a very good candidate to replace fish oil fatty acids, especially as a source of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (ARA), which are known to lower risk of heart disease and reduce the symptoms of depression.
Although the benefits of microalgae as a “food of the future” are increasingly recognised, its potential is still not fully exploited. One of the underexploited features is the mostly bacterial microbiome associated with micro- and macroalgae cultures or on the surfaces of seaweeds. The SIMBA project identifies the associated microbiome and its dynamics under different cultivation conditions. The aim is to apply microbiomes in facilitating cultivation of micro- and macroalgae as a direct or indirect food source.
Microalgae selection and cultivation
In 2002, our NIVA team started a bibliographic review to identify the most promising microalgae strains with relevance to the scope and targets of the SIMBA project (sustainable high-quality food production). Since then, as part of the SIMBA project, we have worked with the Norwegian Culture Collection of Algae (NORCCA), that contains approximately 1,700 strains of microalgae and cyanobacteria. After screening NORCCA, and despite disruptions related to COVID-19, we successfully gathered growth data for 27 of the strains. In parallel to the growth tracking, we used production photobioreactors to produce larger amounts of biomass, which we successfully harvested for the next step of SIMBA.
Image 1: (a) Dr Ana Caterina Almeida (NIVA) in front of a Flow Cytometer holding some of the microalgae included in this work (b) Cultures in the incubator & (c) production reactors where the biomass was produced
Where are we now and future activities?
Now that we know how fast the microalgae candidates grow and that we have retrieved enough biomass, it is time to compare their content on nutritive substances. To do this, we will use cutting-edge analytical technology, LC-HRMS (Orbitrap®), led by Dr Laura Ferrando, Research Team Leader of the Fluid Flow and Environmental Technology Section from the Institute for Energy Technology (IFE), a subcontracted partner in the SIMBA project. The team at IFE will develop a bioprospecting strategy, using a non-selective cascade extraction approach followed by a suspect screening strategy, that will include the broadest possible set of relevant of compounds for the SIMBA. The task is ongoing and is expected to be completed during 2020.
Image 2: Dr Laura Ferrando, from IFE and the LC-HRMS (Orbitrap®)
In cooperation with our partners at CTAQUA, we have just completed a key SIMBA output; the Deliverable 3.2 report, entitled “Description of growth characteristics of selected macro- and microalgae”. Within the document, the team describes the growth profile of 28 microorganisms (including green, yellow-green, and red algae, cyanobacteria and diatoms) together with one macroalga (Ulva ohnoi). With the biomass gathered from 27 strains of microalgae and cyanobacteria and the bioprospecting data provided by IFE, we will assess the suitability of the biomass as a supplement for fish food and recommend the best strains for this purpose. Together with IFE, we will identify from this sample, the best producers of the antioxidant pigment astaxanthin.
Written by Carlos Escudero, NIVA. Since writing this article Carlos has left NIVA, we wish him all the best in his new role. For more information on this work, please contact Malcom Reid (firstname.lastname@example.org).