Isolation, characterization and antimicrobial potential of Ulvan from abundant green marine macroalgae, Egypt

Ulvan, a sulfated polysaccharide with distinctive structural properties and promising biological applications, was extracted from various abundant marine macroalgae (Ulva fasciata, Caulerpa racemosa, and Halimeda tuna) which were collected from Port Said on the Mediterranean Sea and Hurghada on the Red Sea, Egypt. The ultrasonic assisted extraction (UAE) method proved to be the most efficient method for ulvan extraction compared to acid extraction (AE) and hot water extraction (HWE) methods. U. fasciata exhibited the highest ulvan yield, as well as the highest molecular weight (120x105 g/mol). Ash content was relatively low for all species, but there was a notable difference in moisture content and pH. Principal component analysis (PCA) revealed that ulvan showed a positive correlation with pH and ash content. Ulvan obtained from U. fasciata possessed superior physical properties, including higher specific and reduced viscosity (0.57 and 4.43 dL/g, respectively). FTIR and TGA analysis confirmed the presence of characteristic functional groups associated with ulvan. Moreover, the extracted ulvan demonstrated significant antimicrobial activity against several pathogenic microorganisms, highlighting its potential for various applications in the pharmaceutical and food industries.