Comparison of EPS Extraction Efficiences from Spirogyra fluviatilis by Chemical and Physical Extraction Methods

The algal extracellular polymeric sustances (EPS) have been studied as natural resources for a number of applications. For a macroalgae Spirogyra fluviatilis, the aboundant extracellular matrix on the surface of algae cell. EPS has a gel-like structure that could fractioned into loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS). The contents and extraction rate of EPS were compared two chemical (formaldehyde-NaOH and NH4OH) and two physical (ultrasonication and heating) extraction methods. The analysis demonstrated that extraction rates of EPS followed heating (7.94 mg g-1 fresh algae) > ultrasonication (5.02 mg g-1 fresh algae) > formaldehyde-NaOH (3.12 mg g-1 fresh algae) > NH4OH (2.01 mg g-1 fresh algae). The protein to polysaccharides ratio (P/S) in EPS is between 0.23 to 0.35 by chemical methods and between 0.27 to 0.37 by physical methods. The P/S ratio is LB-EPS is higher than TB-EPS. The results indicated that the EPS could be efficiently extracted by the heating method, the influence of P/S ratios were obvious different.