Extraction and Characterization of Alginate Biopolymer from Abundant Brown Seaweeds, Hurghada, Red Sea, Egypt

Brown seaweed is the main source of alginates biopolymer, which has been widely employed in various technological fields. The economic importance of seaweed spans multiple industries, offering sustainable solutions that can enhance food security, health, and environmental sustainability. In our study, five abundant brown macroalgal species were collected from Hurghada, Red Sea (Padina boergesenii, Hormophysa cuneiformis, Polycladia myrica, Turbinaria turbinata and Sargassum aquifolium) for alginate extraction and characterization. The alginate yield varies across the different species. T. turbinata produced the highest alginate yield (35.1 ± 1%), while P. boergesenii yielded the least (18.3 ± 0.5%). The alginate molecular structure was characterized using FTIR, TGA and viscosity measurement. The average molecular weight of alginates varies from 9.04 × 105 g/mol for T. turbinata to 1.2 × 105 g/mol for P. boergesenii. There is a direct correlation between the alginate yield and molecular weights. Furthermore, T. turbinata and S. aquifolium species demonstrate a potential economical source for high quality Na-alginates for various ecofriendly applications.