POLYSACCHARIDES FROM ALGAE .49. ISOLATION OF ALGINIC ACID, SULFATED XYLOGALACTAN, AND FLORIDEAN STARCH FROM CALCAREOUS RED ALGA BOSSIELLA-CRETACEA (P-ET-R) JOHANSEN (RHODOPHYTA, CORALLINACEAE)

Sulfated xylogalactan, sodium alginate, and floridean starch were isol ated from the calcareous red alga Bossiella cretacea by its sequential extraction with dilute hydrochloric acid, sodium carbonate solution, and hot water followed by appropriate purification procedures. Based o n the amylolysis results, properties of an iodine complex, and H-1 and C-13 NMR spectra, the floridean starch was characterized as a branche d alpha-D-glucopyranan of the amylopectin type with the average length of the linear chains being about 14-18 glucose residues. The xylogala ctan contains D-galactose, L-galactose, D-xylose, and sulfate in a nea rly equimolar ratio and does not contain any 3,6-anhydrogalactose, whi ch was scarcely formed after the alkali treatment of the polysaccharid e. The alginic acid was characterized by monosaccharide composition an d C-13 NMR spectrum; it contain more beta-D-mannuronic than alpha-L-gu luronic acid residues (the M/G ratio was established as ca. 0.5), and its monosaccharide residues were shown to be arranged in blocks along the polymer chain. The data obtained demonstrate the unusual polysacch aride composition of calcareous red algae belonging to the family Cora llinaceae.