Antioxidant Compounds in Microalgae and Cyanobacteria: A Sustainable Source of Bioactive Molecules

The search for antioxidant compounds from aquatic or marine environments to cope with the harmful effects of reactive oxygen species (ROS) is one of the major challenges in contemporary blue biotechnology. Among marine microorganisms, microalgae have emerged as promising candidates for the discovery and production of natural bioactive molecules with antioxidant properties. This review highlights the potential of microalgae and cyanobacteria as a sustainable source of antioxidant compounds and examines their growing relevance in biotechnology and pharmaceutical applications. A broad range of antioxidant metabolites produced by microalgae, including carotenoids, fatty acids, vitamins, polyphenols, and flavonoids, has also been discussed, with particular emphasis on their antioxidant mechanisms and bioactive properties. This review also integrates antioxidant mechanisms with the physiological and metabolic responses, underlying antioxidant production and sustainable strategies used to enhance their accumulation. Furthermore, microalgae offer the advantage of sustainable production systems, with the potential to enhance the biosynthesis and accumulation of valuable compounds through optimized cultivation strategies. Thus, different sustainable approaches aimed at increasing antioxidant compound production or reducing operational costs in microalgae cultivation are discussed to identify efficient and economically viable processes that maximize the biotechnological potential of these microorganisms for future industrial applications.