Comparison of Two Extraction Methods for Spirogyra Extracellular Polymeric Substances

Microbial extracellular polymeric substances (EPS) have been considered as important renewable resources and technologies. Lately many studies are looking for valuable EPS as well as algae with production potentials and corresponding extraction methods. Spirogyra spp. is a genus of large filamentous green algae commonly found in freshwater areas? Under natural circumstances, Spirogyra spp. excretes large amounts of EPS and forms a mucilage layer. This study used two algal EPS extraction methods such as ultrasonication and heating to compare the extraction yields of EPS and the levels of its primary components of polysaccharides and proteins. The results indicated that the extraction yields of EPS using heating and ultrasonication are 29.4 mg EPS/g-fresh algae and 15.8 mg EPS/g-fresh algae, respectively. The ratio of polysaccharides to proteins in EPS is around 1.85 to 2.16, which is not a significant difference between the two extraction methods. In other words, the level of polysaccharides is always higher than the level of proteins in EPS extraction with both two methods. This study exhibited the developmental potential of Spirogyra and the industrial application of EPS by exploring extraction methods of Spirogyra and the features of EPS.