Immense potential remains to be realised

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. ey 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. e 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. e EU has identi ed 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 biobased products2. 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. e use of wastewater o ers collateral bene ts 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 database3 o ers an updated overview of the existing enterprises operating at di erent 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, 20154).

Photobioreactors the preferred system to grow microalgae in Europe

Among the identi ed 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. e 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 alga’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 fth 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