Viability assessment of an integrated valorisation strategy for aquaculture fish waste

ABSTRACT The increasing production of aquaculture fish has led to a parallel growth in processing by-products, highlighting the need for sustainable and economically viable valorisation strategies. In this study, the feasibility of an integrated marine biorefinery for the valorisation of aquaculture by-products is assessed, using turbot ( Scophthalmus maximus ) residues as a representative case. The proposed biorefinery focuses on the production of fish protein hydrolysates (FPHs), gelatine, fish oil and a solid residual fraction, based on pilot-scale operational data and scaled up to industrially relevant conditions. An integrated approach combining Life Cycle Assessment (LCA) and Techno-Economic Assessment (TEA) is applied to evaluate environmental performance, economic viability and key process hotspots. The environmental results indicate that energy demand, particularly for thermal operations, together with reagent use and water consumption, dominate the overall impacts, while alternative energy supply scenarios based on cogeneration significantly improve environmental performance. From an economic perspective, both stand-alone and integrated implementation scenarios show positive indicators, with higher profitability achieved when the biorefinery is integrated into existing aquaculture facilities. Sensitivity analyses reveal that economic performance is strongly influenced by product market prices, especially FPHs, which account for the largest production volumes. Overall, the results demonstrate that marine biorefineries based on aquaculture by-products can represent a viable pathway towards circular bioeconomy models, provided that energy integration and market-related uncertainties are carefully addressed.