Diatoms: A Nutritional Potential for Sustainable Applications: From Biochemical Composition to Bioeconomy and Climate Resilience

Diatoms are ecologically important microalgae with considerable potential for sustainable applications owing to their diverse biochemical composition and environmental adaptability. This review examines their nutritional composition, including proteins, lipids, carbohydrates, omega-3 polyunsaturated fatty acids, pigments and other bioactive compounds, and evaluates their applications in aquaculture, nutraceuticals, functional foods and emerging biotechnological systems. Particular attention is given to species-specific variation in biochemical composition and the influence of cultivation conditions, nutrient availability, light, temperature and growth phase on biomass productivity and metabolite accumulation. Protein abundance is considered separately from nutritional quality, while fatty acid profiles are discussed in relation to the quantitative evidence available for individual taxa. The review further explores diatom-based biorefinery approaches and their contribution to a circular bioeconomy through the recovery of multiple value-added products from biomass. Climate resilience is addressed by examining how environmental change and cultivation stressors may alter diatom growth, biochemical composition and the reliability of biomass production. Despite their potential, broader application remains constrained by strain-dependent variability, incomplete nutritional characterization, analytical inconsistencies, downstream processing costs and challenges in scaling cultivation systems. Standardization of analytical methods, systematic strain selection, improved cultivation strategies and scalable production systems are therefore essential for reliable product characterization and commercial translation. Integrating nutritional evidence with environmental sustainability and techno-economic considerations may strengthen the role of diatoms in sustainable food and feed systems and the emerging bioeconomy.