Study on the Microwave Extraction of Polysaccharides in Marine Alga

Polysaccharides were extracted from Chlorella autotrophica with the microwave method. In order to find out the best extraction condition, 4 factors of extraction, that is, temperature, time, medium solution pH and microwave power were adopted to build a orthogonal optimization experimental system and each factor was respectively examined. Results show that under the best condition of 70 ℃ , 30 min, pH = 7 and 600 w, the recovery ratio is 291.13 mg/g (crude polysaccharide / dried weight) which is higher than that by traditional hot water extraction, 78.52 mg/g (crude polysaccharide / dried weight). The crude polysaccharides collected by two extraction methods have similar IR spectra. Comparing with traditional hot-water immersed method, the microwave extraction will not destroy the chemical structure of polysaccharide, but consume less time and get higher recovery ratio.