The Sea2Land1 project is a 4-year collaborative Innovation Action (IA) funded by the EU in the frame of the Horizon 2020 programme. Based on the circular economy model, SEA2LAND promotes the production of bio-based fertilizers (BBF) in the EU from its own raw materials in order to reduce the soil nutrient imbalance in Europe. The basis of the project is the regional production of BBF from fishery and aquaculture byproducts by developing dedicated demonstration pilots that can be replicated across Europe, boosting local growth. 26 partners from 11 countries are participating in the project. 9 technologies are developed on the basis of 7 demonstration pilots implemented in 6 representative areas of the European fishing and aquaculture sectors. For the Atlantic area case study, the project aimed at producing BBF’s from fish byproducts2 using ThermoMechanoChemical (TMC) fractionation by twin-screw extrusion. The process was developed on the fractionation of 50/50 mix of heads/frames of Steelhead trout (ST) and efficiently transferred to the same mix of Sturgeon (S). Both species are interesting sources of nutrients: 7-8% N/DM, 2-4% P/DM and 0.5-1.0% K/DM but also contains between 40% and 50% of lipids. Configured as an extraction process, extrusion represents an industrial continuous process able to provide simultaneously a solid and a liquid fraction 3. The use of TMC process for fertilizers production is an innovative approach allowing the recovery of not only BBFs with an agronomic value but also fish oil to reach a ZERO-waste process. After process development and optimization at TRL4-5, pilot scale trials at TRL6 were achieved at a feeding rate of 20 kg/h in fish by-products. From 20 kg fish by-products, 2 fertilizing products are obtained for each specie. For ST, 4.2 kg of an organic solid BBF (9.4 N/DM; 19 % Lipids/DM), 6.7 kg of a liquid organic BBF (13.9% N/DM) and 2.0 kg of fish oil. For S, 4.0 kg of solid BBF (9.8% N/DM; 17% Lipids/DM), 6.2 kg of liquid

BBF (10.5% N/DM) and 1.3 kg of fish oil are obtained. Both extracted oils could be highly prized by the human food and animal feed sectors 4. The efficiency of the process was evaluated in terms of N, P, K recovery in the solid BBF fraction and oil recovery. For ST, nutrients recovery was: N > 90%, P > 97% and K > 80%. More than 50% of oil was also recovered. The solid BBF’s from ST was evaluated for pot and field trials. It is conformed in terms of nutrients, heavy metals and pathogens. It is considered as high Pavailable, medium N-available and good C/N ratio.