## 4 Sustainability and Circular Bio-Based Solutions in Marine-Based Food Production  
As the demand for innovative and sustainable food ingredients continues to rise, the incorporation of marine-based compounds into food products, whilst presenting a valuable opportunity for innovation, faces specific and unique challenges. Bio-based products and value chains' development is a key component of the European Union's Circular Economy Action Plan and the EU Green Deal, which commits Europe to becoming a climate-neutral continent by 2050 [49]. With consumers increasingly searching for healthier and environmentally friendly food options, the idea of using marine-derived compounds in food products is gaining traction. With increasing concerns about overfishing, habitat destruction, and climate change, stakeholders across the food industry are actively exploring ways to ensure the long-term viability of marine resources. However, the environmental impact of marine-based food production needs to be considered. While traditional production practices of marine-based food products have significant environmental impacts, sustainable production could be the solution. Aquafeed production is a major contributor to these impacts, representing only 1.1% of total production food but with a calculated environmental footprint of about 9.9% of the global footprint [50]. Even though sustainable practices are being adopted, it also presents environmental challenges that need careful consideration. One of the primary concerns is the overexploitation of marine resources, particularly algae and other marine organisms [51]. Unsustainable harvesting practices can lead to habitat destruction, reduced biodiversity, and the depletion of essential marine ecosystems. Sustainable management practices, such as marine zoning, which has been implemented in the Canadian Maritimes for _Ascophyllum nodosum_ harvests, can help mitigate negative effects on marine habitats [52; 53]. Another key concern is that the energy consumption associated with marine extraction and processing, particularly in large-scale operations, must be minimized to balance environmental benefits and costs [54]. Technological advancements such as energy-efficient extraction methods and sustainable aquaculture practices can further reduce the ecological impact of marine food production. Additionally, marine-based ingredients like seaweed can play a key role in mitigating climate change by acting as carbon sinks, absorbing CO\({}_{2}\) from the atmosphere [55]. This ability to sequester carbon positions marine production as an environmentally beneficial option when managed responsibly. One key approach to promoting sustainability is the adoption of circular bio-based solutions contributing for the development of a \"zero waste\" food system [42], with a view to minimise the generation of waste material [56]. These solutions aim to minimize waste and maximize resource efficiency by closing the loop on production processes, effectively turning former waste into valuable inputs for new products or processes. The integration of bio-economy and biorefineries into the production system is a valuable pathway for the practical implementation of a circular economy [57]. Marine biomass, from algae to marine by-products, are being extensively studied as a potential resource to be explored in biorefineries, offering valuable pathways for the practical implementation of this alternative materials in diverse conversion technologies. Within the wide vast of biorefinery categories, those where cascade processes are applied allow diverse products under a zero-waste approach to be obtained and in this way to directly contribute for a blue economy [58]. As an example, several studies have been conducted in relation to the use of biorefineries to process seaweed biomass to obtain extract fractions rich in distinctive compounds, as explored by [PERSON] et al. [58] in a cascade extraction system to extract non-polar to polar compounds, or as described by [PERSON] et al.