Detection of Polysaccharides in Lingbea Algae Using Different Techniques and Evaluation of Their Biological Applications

The main focus of this study was to determine the chemical composition of Lyngbya algae using various analytical methods. Thus, algae samples were collected from the marshes of Thi-Qar Governorate in southern Iraq during the spring of 2024. FTIR analysis revealed distinct absorption bands, including a broad O–H stretch at 3348.42cm⁻¹ and a C=O band at 1654.92cm⁻¹, confirming the presence of alginate. A distinct S=O stretch at 1230.00cm⁻¹ indicated a high sulfate content characteristic of carrageenan. Additionally, an O–H band near 1075.00cm⁻¹ suggested the presence of agar. HPLC results highlighted the chemical complexity of Lyngbya's major components. Within the alginate fraction, alginate appeared as the dominant compound, with a retention time of approximately 4:38.9 minutes and accounting for 35.462% of the total composition. Other significant but nonspecific peaks were also observed. In a separate analysis focusing on carrageenan, the importance of this sulfated polysaccharide was evident. Agar was identified as a minor component, with a retention time ranging from 5:43 to 6:07 minutes, representing 3.209% of the total surface area. Combined spectroscopic and chromatographic analyses confirmed the biochemical richness of Lyngbya, highlighting not only the structural roles of alginates, carrageenan, and agar in cell preservation and ecological balance but also their contributions to defense mechanisms and metabolic regulation.