Fermentative valorization of edible algae: nutritional potential, food applications, safety considerations, and industrial challenges

Edible algae, including microalgae and macroalgae, are recognized as sustainable aquatic bioresources for future food systems, with high areal productivity, low reliance on arable land and freshwater, and rich nutrients including proteins, polyunsaturated fatty acids, pigments, minerals, vitamins and functional polysaccharides. Yet their wider application in mainstream foods is limited by low digestibility, rigid cell walls, marine off-flavors, variable safety and high processing costs. This review examines the nutritional potential, food applications, fermentation strategies, safety considerations and industrial bottlenecks of edible algae, focusing on fermentation-mediated valorization as an enabling strategy beyond conventional preservation. Lactic acid, alcoholic and mixed-culture fermentation can boost shelf stability, release intracellular nutrients, modulate sensory attributes, generate bioactive metabolites, and support circular use of residual algal biomass. Meanwhile, advanced technologies like enzyme-assisted extraction, non-thermal extraction, microfluidics and nanoencapsulation help enhance ingredient functionality and bioactive delivery. The review also notes that the future value of algae-based foods relies on matrix-specific formulation, standardized safety control for heavy metals and iodine, strain improvement, biorefinery integration and consumer-oriented sensory design. Overall, fermentative and precision-processing strategies offer a promising route to transform algae from niche supplements into safe, palatable, multifunctional ingredients for sustainable food innovation.