The potential of algae as a future aquaculture product in Finland

The cultivation of algae and cyanobacteria and the products derived from them are a subject of much talk and writing at present. There is also an abundance of basic and applied research on the subject throughout the world. However, in Finland we will not be quite ready to enjoy domestic edible macroalgae products within the next few years.

4x5 aspect ratio

Kari Jokinen & Esa Tyystjärvi

Kari works as a Principal Scientist at the Natural Resources Institute Finland and Esa as a Docent at the University of Turku

The environmental conditions in Finland pose challenges for algae cultivation

The globally and commercially important cultivation of algae occurs almost exclusively outdoors since algae require light and heat in addition to nutrients.

In recent years, new ways of utilising the resources of domestic marine areas have been explored, such as a joint research project involving eight Baltic Sea countries. Here, interest was focused on collecting and cultivating micro- and macroalgae, mussels, as well as reeds.

The results of the project have been promising in terms of improving the status of the environment, as this cultivation removes nutrients from the sea. However, at the current commodity prices of such raw materials, such cultivation is not economically viable unless the farmer is paid a separate compensation for withdrawing nutrients.

The natural climate and temperature in the northern climate zone do not allow for year-round and economically profitable algae cultivation outdoors. However, cultivation can take advantage of the opportunities offered by new technology. Seasonal and weather variations are irrelevant if the algae are grown in indoor photobioreactors.

Algae are effective in wastewater treatment and nutrient recycling

According to many studies, algae and cyanobacteria can be effectively grown in wastewater where they are particularly effective in reclaiming phosphate and nitrogen.

This naturally combines nutrient recycling and biomass production with wastewater treatment. Urban, industrial, and agricultural wastewater can be used as nutrient sources. This would further reduce nutrients in effluent discharges to the Baltic Sea.

The biological utilisation of algae can be combined as an integral part of fish aquaponics, also known as circular aquaculture. Here, algae remove nutrients, such as ammoniacal nitrogen, which is harmful to fish. In the best-case scenario, a protein-rich algae biomass can be used as a raw material for fish feed.

In recent years, combining algae cultivation with year-round greenhouse cultivation has been explored. In this system the surplus light energy would be utilised, meaning that a separate, heated space is not needed for cultivation. At best, growing algae in a greenhouse complements the entrepreneur's product range and opens up new business opportunities.

 A close-ip photo of duckweed.
The cultivation technology of duckweed and its versatile exploitation potential are explored at the Natural Resources Institute Finland.

Algal refining produces energy and added-value products

Combining algae cultivation with an existing industry also offers new opportunities to produce a variety of products from algae biomass in a type of biorefinery, such as lipids, biogas, and fertilizers.

For example, the pulp and paper industry produces carbon dioxide, heat, and electricity, as well as waste-water, all of which are required for algae cultivation.

The most commonly produced energy products from algae include biodiesel, bioethanol, and biogas. However, a wide range of other organic molecules can also be refined from algal biomass. High-value products include various lipids, pigments, proteins, and carbohydrates. Such compounds are used, among other things, in the cosmetics, pharmaceutical, food, and feed industries. 

The industrial cultivation of algae is a possible sector in the future

According to current views, the year-round and industrial cultivation of different algae in Finland is technically possible when combined with the reclamation of wastewater.

The economic viability of farming can be significantly improved by integrating it into existing infrastructure.

The challenge for research and development is to find species of algae and cyanobacteria that are capable of isolating the most valuable compounds from biomass in an economic manner. At our latitudes, algal production based solely on energy products is hardly economically justified.