Sustainable processing of seafood byproducts through enzymatic technologies: A comprehensive review

Commercial fishing operations often discard up to half of their raw catch, including scales, shells, frames, viscera, and other less desirable parts. This discarded biomass, coupled with low-value by-catch, poses significant environmental challenges due to its rapid decomposition. However, these materials represent an underutilized source of valuable compounds such as proteins, enzymes, carotenoids, fats, and minerals. This review consolidates recent advances in enzymatic technologies for the sustainable processing of seafood byproducts. It highlights the role of fishery-derived enzymes such as proteases, lipases, chitinases, alkaline phosphatases, transglutaminases, and hyaluronidases in the extraction, modification and valorization of marine biomolecules. Particular attention is given to enzymes from cold-adapted species, which offer high catalytic efficiency at low temperatures, enabling energy-efficient processing while maintaining product quality. The review identifies outstanding research gaps, including large-scale enzyme stabilization, recovery efficiency, and integration of biocatalytic systems with green extraction technologies. By summarizing these innovations and challenges, this work provides a framework for developing sustainable, enzyme-driven seafood waste valorization strategies that align with circular bioeconomy principles.