Extraction of porphyran from Porphyra yezoensis Ueda F. narawaensis Miura.

A best search for the most efficient extraction condition of sulfated polysaccharide (Porphyran) from Porphyra yezoensis UEDA F. narawaensis MIURA was made. The highest yield was obtained by the following procedure: Raw algal fronds were treated with 3.7% formaldehyde solution in a flask closed with a stopper at 30°C for 24h. After addition of 2 times volume of distilled water, the suspension was heated at 100°C with stirring for 12h. The extract was cooled at room temperature and filtered through a layer of diatom earth. The clarified filtrate was dialyzed in a Visking cellophane tube against running tap water for 24h, and evaporated to 1/4 of its original volume under reduced pressure, to this was added 4 times volume of ethanol at room temperature. The gelatinous precipitate collected by centrifugation was washed with ethanol, and acetone, and dried at 30°C for 12h. Gel-filtration on Sepharose CL-2B showed that the higher molecular weight polysaccharides were extracted by treatment with a higher temperature and a lower molecular weight components which was eluted the position to the Vi increase in the amount with the length of extraction time.