Transforming Beach-Accumulated Seaweed into High-Value Bioactive Products: A Recycling Perspective

Due to large-scale macroalgal blooms, nutrient enrichment, and changes in ocean circulation brought on by climate change, beach-accumulated seaweed (BAS) has quickly become a global environmental and waste-governance concern. Despite degradation and contamination during beach stranding, BAS retains valuable bioactive compounds, including sulfated polysaccharides, phlorotannins, pigments, proteins, peptides, and lipids, which exhibit anti-inflammatory, antioxidant, antimicrobial, antiviral, immunomodulatory, anticancer, and metabolic regulatory activities. This review critically evaluates BAS as a sustainable bioresource by integrating current knowledge on biomass composition, degradation-associated challenges, bioactive properties, valorization pathways, advanced extraction technologies, safety validation, regulatory considerations, and emerging commercialization opportunities. Attention is given to sustainable valorization pathways, ranging from composting and bioenergy production to the recovery of high-value bioactives through enzyme-assisted, green, and advanced extraction technologies. The review further discusses policy and regulatory gaps, contamination challenges, safety validation requirements, and life-cycle sustainability considerations that currently limit industrial adoption. Finally, emerging opportunities involving metabolomics, microbial bioprocessing, artificial intelligence, automation, and nanotechnology are explored as future directions for transforming BAS into a standardized and economically viable feedstock within the circular blue bioeconomy. Establishing harmonized regulatory frameworks and integrating BAS management with Sustainable Development Goals (SDGs) 12 and 14 will be critical for enabling sustainable resource recovery and long-term coastal resilience.