Comparative Yield and Physicochemical Properties of Marine Bioproduct Sodium Alginate from the Brown Seaweeds <i>Hormophysa Triquetra</i> and <i>Carpomitra Costata</i>

ABSTRACT This work intended to extract and quantify sodium alginate from brown algae Hormophysa triquetra ( H. triquetra ) and Carpomitra costata ( C. costata ) and to verify its purity with spectroscopic methods. Sodium alginate extraction using brown algal biomasses ( H. triquetra and C. costata ) produced 22.55% ± 0.74% and 26.8% ± 0.61%, respectively (dry weight). The extracted alginates showed pH values of 9.65 and 9.1, viscosities of 55.8 cP and 95.5 cP, and moisture contents of 12.5% and 9.2%. Carbohydrates, proteins, and lipids were 74.2 %± 1.5% and 82.5% ± 0.9%, 0.64% ± 0.2% and 0.85% ± 0.3%, and 0.5% ± 0.01% and 1.4% ± 0.1% for H. triquetra and C. costata , respectively. Phytochemical screening revealed the absence of alkaloids, terpenoids, steroids, tannins, flavonoids, phenols, glycosides, and phlorotannins, which confirmed the purity of the obtained sodium alginate. 1 H‐NMR and FTIR spectroscopic analyses further confirmed the structural features of the obtained sodium alginate especially from C. costata . The information provided indicates that high‐purity sodium alginate from C. costata and to a lesser extent H. triquetra are effective sources for further biotechnology and industrial applications.