The European fishing industry generates around 5.2 million tonnes of waste per year from the processing of marine fisheries, most of which is not reused. However, this waste contains high-value minerals such as nitrogen, phosphorus, potassium, iron, copper or zinc, as well as vitamins and other compounds, which could be recovered and used for agricultural production.
In this context, the NEIKER technology centre, a member of the Basque Research and Technology Alliance (BRTA), is working on the development of new fertilisers that include in their composition microalgae produced from waste from different tuna canneries in the Basque Country. Specifically, brines, waters with a high salt content used in cooking fish, which contain nutritional compounds in the form of leftover tuna skin, meat and fat. These brines, rich in nutrients and minerals, are being used as a culture medium for the production of microalgae.
As part of this research, with the collaboration of the AZTI technology centre and several Basque canning companies, a bioremediation process has been tested to obtain microalgae with high added value for the agricultural industry, recycling all the nutrients and minerals present in the brine from cooking the fish.
In particular, this biological treatment consisted of using the brine as a culture medium for a heterotrophic microalgae, i.e. one that is capable of using organic matter to grow, from the Pobeña marshes (Bizkaia).

Nutrient-rich microalgae
The process is simpler than it seems at first glance. “These microalgae incorporate part of the organic matter present in the cooking water during their growth process. Specifically, they ‘eat’ proteins, oils and other nutritional compounds present in the waste”, explains Sonia Suárez, researcher at NEIKER’s Plant Production and Protection department.
This process lasts approximately 3-4 days, a period in which the microalgae are capable of consuming up to 90% of the nitrogen in the proteins and amino acids present in the brine.
Once harvested, the microalgae are used in the formulation of agricultural products such as biofertilisers or biostimulants. In this way, the nitrogen from the fish, captured by the algae, reaches the soil, favouring the production of agricultural crops.
This research opens the door to the reuse of a large quantity of minerals present in this organic waste from the fishing industry. “In this way, we are contributing to the development of nutrient-enriched biofertilisers with high added value for the European agricultural industry,” Suárez points out. In particular, the use of this type of waste could make it possible to recover around 1.8 million tonnes of nitrogen for agriculture.

Converting fish waste into biofertilisers
This work has been carried out within the framework of the European SEA2LAND project, funded by the European Union’s Horizon 2020 programme with the aim of converting tonnes of waste from the fishing industry into biofertilisers. With a budget of 7.7 million euros, this ‘from the sea to the land’ strategy proposes the application of more than 10 technologies in 7 case studies in 6 representative areas of the European fisheries sector (North Sea, Baltic, Cantabrian, Mediterranean and Adriatic Seas, as well as the Atlantic Ocean).
To this end, different technological processes are being optimised, such as nutrient capture and recycling processes with microalgae, advanced composting, biodrying, concentration and extraction by freezing, pyrolysis or chitin extraction, among other techniques, which will make it possible to generate bio-based and tailor-made fertilisers, both for crops and local conditions and for export.
Coordinated by NEIKER, the SEA2LAND project involves 25 partners from 11 different countries: Universite de Liege (ULIEGE), Fibl Europe – Forschungsinstitutfur Biologischen Landbau en Europa (FIBL EU) and Universiteit Gent (UGENT) from Belgium; IPS Konzalting Doo Za Poslovne Usluge (IPS) from Croatia; Nutriloop Ou (NUTRI) and Eesti Taimekasvatuse Instituut (ECRI) from Estonia; Center Regional D’Innovation et de Transfert de Technologie Agroressources (CATAR), Institut National Polytechnique de Toulouse (INPT) and Chambre D’Agriculture des Pyrenees Atlantiques (CAPA) from France; Universita Politecnica delle Marche (UNIVPM), Universita degli Studi di Milano (UMIL) and Societa Cooperativa Pescatori Molluschicoltori (CO. PE. MO) of Italy; Aquabiotech Limited (ABT) of Malta; Gronn Gjodsel As (Grønn), Norsk institutt for biookonomi (NIBIO) and Norsk Landbruksradgiving Nord Norge (NLR-NN) of Norway; Instituto de Soldadura e Qualidade (ISQ) of Portugal; Barna SA, Caviar Pirinea SL, AZTI, Fundacio Universitaria Balmes (UVIC-UCC), Fertinagro Biotech SL, Iniciativas Innovadoras Sal (INI) from Spain; Forschungsinstitut Fur Biologischen Landbau Stiftung (FIBL-CH) from Switzerland and the Instituto de Investigaciones Agropecuarias (INIA) from Chile.
SEA2LAND is part of the European strategy to promote the bioeconomy as the economic model of the future. It also forms part of the Basque Government’s commitment to promoting the transition towards the bioeconomy.

NEIKER, a member of the Basque Research & Technology Alliance (BRTA), is a technology centre specialising in the creation of innovative solutions for the agro-livestock and forestry sectors. NEIKER’s main lines of work are the promotion of the sustainability and competitiveness of farms, the search for alternatives to mitigate the effects of the climate emergency on agriculture, the promotion of the bioeconomy to reduce dependence on non-renewable raw materials by creating new economic activities, the rationalisation of phytosanitary products in agriculture and the reduction of the use of antibiotics in livestock farming to minimise the impact of the increase in antibiotic resistance.
As an entity dependent on the Basque Government’s Department of Economic Development, Sustainability and Environment, NEIKER’s activity is aimed at responding to and supporting the strategies that the Basque Government designs for the promotion, development and management of the agricultural, livestock and forestry sector in the Basque Country.

Marine plankton culture (Chlorella sp.) with light and oxygen in Scientific laboratory


Watercolor horizontal seamless border of pink purple cells microalgae microorganisms, microscope bio algae. Concept for cosmetics medicine healthcare print design. Pastel ameoba bacteria, soft oval round shape