Advances and perspectives in farming and exploiting microalgae

by Thomas Jensen

Immense potential remains to be realised

This article was featured in Eurofish Magazine 3 2023.

Microalgae are a large and diverse group of aquatic microorganisms that can perform oxygenic photosynthesis—the conversion of sunlight and carbon dioxide into oxygen and biomass that serves as food, feed, fuel, and fibre. Microalgae are found in various aquatic environments, including oceans, lakes, and rivers as well as terrestrial and extreme habitats.

Microalgae can be grown on non-arable land and in non-drinkable (brackish or marine) water. They show rapid growth and high photosynthetic conversion of light energy to biomass compared to land plants. Nowadays they are considered one of the most promising and largely untapped sources of biomass—with a limited carbon and environmental footprint—for biofuel production, food, and feed, as well as for use in the pharmaceutical, bioplastic, fertiliser, and other industries. The global microalgae market was estimated at USD 1 billion in year 2022 and is projected to reach USD 1.6 billion by the year 2030 expanding at a compound annual growth rate (CAGR) of 5.7% (1).

Europe’s microalgae industry is relatively small

In Europe, microalgae exploitation is still in the early stages of development, but it is a rapidly growing industry with a lot of potential due to increasing awareness of the valuable functional compounds possessed by microalgae. The EU has identified microalgae as a key area of research and development as it is considered a way of contributing to the objectives of the European Green Deal. Enhanced EU production and use of microalgae will support sustainable food and farming systems, economic circularity and bio-based products(2). Other EU documents such as the Farm to Fork Strategy, the Strategic Guidelines for EU Aquaculture, and the Sustainable Carbon Cycles Communication recognise the potential of algae, both macro and microalgae, for the blue carbon economy.

Sustainable and circular bioeconomy criteria may be met by using suitable wastewater rich in nutrients (phosphorous, nitrogen, trace metals) for algal cultivation. The use of wastewater offers collateral benefits in the form of adding to the freshwater supply, reducing algae biomass production costs, which are still quite high, and mitigating the environmental impacts of wastewater. In the EU algae are cultivated by companies in several countries. A recent JRC algae industry database(3) offers an updated overview of the existing enterprises operating at different steps of the algae value chain (most biomass producing are also biomass processing enterprises) and based in 20 EU Member States as well as in Iceland,
Norway, Switzerland, and the UK. In the cited work data belonging to the genus Arthrospira, commonly referred to as Spirulina, have been separated from data on other microalgae as Spirulina has a long history of use and it can be commercialised in the EU without the need to comply with Regulation (EU) 2015/2283 on novel foods (EU, 2015(4)).

Photobioreactors the preferred system to grow microalgae in Europe


Among the identified enterprises, 21% of them cultivate microalgae in production plants based in 17 European countries and 52% of them cultivate Spirulina in 15 European countries. France is the country with the largest number of cultivation and production enterprises (169), followed by Spain, Ireland, Norway, and Italy with more than 20 enterprises in each country. The mostly cultivated species of microalgae in terms of number of enterprises are Chlorella spp. (31%) and Nannochloropsis spp. (28%); the cultivation system employed (61% of the total) is a closed plant consisting in photobioreactors (PBRs). PBRs guarantee a better crop protection and control of the growth environment; it is therefore easier to reach higher biomass yield and to direct algal carbon allocation to target compounds with respect to cultivation in open ponds. However, PBRs require higher energy input and risk photosynthetic build-up of O2 (with a consequent inhibition of algal growth).

On the contrary, Spirulina cultivation employs open ponds in Europe (65% of the enterprises) due to the algae’s ability to thrive at extreme pH which avoids easy contamination by wild algal strains, grazers, and pathogens. Most microalgal biomass produced in EU (from 54% of the enterprises) is allocated to the food and feed markets (food supplements, animal feed and human food). About a fifth of the enterprises belong to the cosmetics and wellbeing industry, another 8% of the enterprises allocate their biomass to produce pharmaceuticals, and 7% to produce fertilisers and biostimulants. Spirulina biomass is, in contrast, almost completely allocated to human food, food supplements and nutraceuticals due to its high nutritional value. Microalgae are rich in high quality proteins, essential amino acids, long chain PUFAs, vitamins, antioxidant molecules
(e.g. astaxanthin, b-carotene, phycocyanin), and mineral salts.

Production of biofuels from microalgae beset by challenges

Microalgae are also suitable as nutritional supplements in livestock feed formulations, for example, replacing fish meal and fish oil in aquaculture. However, exploiting the full potential of microalgae biomass in food production systems is still limited due to a low social acceptability and challenges in policy implementation. Using algal biomass as feedstock for biofuel production suffers from several challenges. The impact of biological and technological constraints on microalgal composition (e.g. lipid content as dry weight percentage) and doubling time raises the cost of raw materials, harvesting and processing. According to a recent paper (5) by an Italian research team in algal physiology based in Università Politecnica delle Marche (Ancona) and led by Dr Alessandra Norici, the most productive species or cultivation plant would still require roughly half the area of Italy (corresponding to the country’s entire stock of arable land) to fulfil 9% of the energy demanded in 2030 by the transport sector—the estimated goal for biofuel quota according to the Sustainable Development Scenario(6) (International Energy Agency, 2020).

Microalgae ­production in Italy is mainly at ­laboratory scale

Italy has 21 producers (20 of them cultivating also or only Spirulina) with a total of 70 employees (Calderon and Lopez, 2022). Most activities concerning the microalgae sector are at university research level and on a laboratory or pilot scale. They often investigate the integration of a side-stream microalgae process for the treatment of domestic/pig farm/agro-industrial wastewaters. Among the challenges facing the development of a microalgae industry in Italy, is the lack of appropriate regulations and incentives to support the development of this sector. In 2018 the Italian Association for the Study and Applications of Microalgae (AISAM, was established. It currently includes over 100 individuals, 20 companies and 2 institutions as its members. It is a non-profit association that aims to promote scientific research and youth training and to support Italian companies in the sector, encouraging exchange and cooperation in the production, processing, and use of microalgal biomass. AISAM activities include conferences, workshops and webinars focused on fundamental and industrial issues. It is also concerned with regulatory and ethical issues, and it cooperates with national and international bodies (such as the Italian ministry of agriculture) to propose guidelines for the industrial
exploitation of microalgae.

For more information, contact:
Dr Alessandra Norici
Università Politecnica delle Marche
Dip. Scienze della Vita e dell’Ambiente
Via Brecce Bianche 60131, Ancona


(1) Microalgae: Global Strategic Business Report, 2023
(2) Towards a strong and sustainable EU algae sector
(3) European Commission, Joint Research Centre, Vazquez Calderon, F., Sanchez Lopez, J., An overview of the algae industry in Europe : producers, production systems, species, biomass uses, other steps in the value chain and socio-economic data, Publications Office of the European Union, 2022,
(4) Regulation (EU) 2015/2283 of the European Parliament and of the Council of 25 November 2015 on novel foods, amending Regulation (EU) No 1169/2011 of the European ­Parliament and of the Council and repealing Regulation (EC) No 258/97 of the European Parliament and of the Council and Commission Regulation (EC) No 1852/2001.
(5) Gerotto C, Norici A and Giordano M (2020) Toward Enhanced Fixation of CO2 in Aquatic Biomass: Focus on Microalgae. Front. Energy Res. 8:213. doi: 10.3389/fenrg.2020.00213
(6) International Energy Agency (2020). Transport Biofuels -Analyses. Available online at: (accessed June 24, 2020).­Parliament and of the Council and repealing Regulation (EC) No 258/97 of the European Parliament and of the Council and Commission Regulation (EC) No 1852/2001.

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