Global optimization for simultaneous extraction of oil and polysaccharides from Schizochytrium limacinum by enzyme-assisted three-phase partitioning

Marine algae are important sources of biological substances. Polysaccharides and oil in algae have a broad range of biological activities. The aim of our study was to develop a novel method for the extraction of polysaccharides and oil from Schizochytrium limacinum by enzyme-assisted three-phase partitioning. S. limacinum was pretreated by protamex hydrolysis for 2 hr, at pH 3.0, temperature of 45°C, and enzyme concentration of 2.0%. Response surface was used to analyze the three-phase extraction and Box–Behnken design was employed to model algae oil and polysaccharides. The following optimal conditions were obtained by global optimization: 34% mass fraction of ammonium sulfate, 1:2.4 ratio of slurry to t -butanol, 41 min time, 40°C temperature, 35.69% oil yield, and 5.16% polysaccharides yield. The polysaccharides exhibited potential antioxidant activity in DPPH, ABTS, and reducibility assay. The results indicated that the algal polysaccharides may be used as a natural antioxidant in food. Practical applications The application on Schizochytrium limacinum is mainly to extract DHA, but the algal polysaccharide has not been used. Algae oil and polysaccharides are simultaneously extracted from S. limacinum by enzyme-assisted three-phase partitioning (EATPP). The results suggest the EATPP is a novel method to obtain simultaneously oil and polysaccharides.