The brown seaweed genus Zonaria: major features, biotechnological potential, and applications

This review is a broad overview of species of the genus Zonaria, a relevant taxonomic grouping within the brown algae, considering data regarding the most common species. The article covers: classification, taxonomy, morphology, ecology, biochemical composition, biological activities, extraction procedures, and possible applications are analysed and discussed. The majority of the Zonaria species are distributed worldwide and encompass different environments. There is a total of 18 species, with Z. diesingiana, Z. farlowii, Z. tournefortii, and Z. turneriana being the most studied. However, even these species exhibit significant knowledge gaps. The study of Zonaria seaweeds is also rendered more difficult due to taxonomical uncertainties and the over-reliance on phenotypic traits for the identification of the genus and particular species. The biological traits of Zonaria spp. point to a highly adaptable seaweed; these organisms can modulate nutrient uptake depending on prevailing abiotic and biotic conditions. The study of the biochemical composition of Zonaria species enabled identification of potential bioactive compounds, such as phenols, sterols, fatty acids, and other lipids and lipophilic substances. Furthermore, relevant bioactivities (antioxidant, anti-microbial, and anti-cancer) have been reported in some of the species. The molecules underlying these bioactivities may be extracted through the application of highly innovative green technologies. There are already some studies in this direction, but many more are needed. Possible applications of Zonaria biomass or extracts thereof could encompass human and animal nutrition, but also the plant-stimulant market. The incorporation of Zonaria spp.-derived bioactivities to novel products, e.g., cosmetic, cosmeceutical, nutraceutical, and pharmaceutical applications is also within genuine reach of sustainable utilisation.