Cell-wall polysaccharides from the marine green alga Ulva “rigida” (ulvales, chlorophyta). Extraction and chemical composition

Cell-wall polysaccharides from the green seaweed Ulva “rigida” were extracted sequentially with oxalate, 1 and 4 M KOH, sodium chlorite and 4 M KOH again. The chemical composition of the soluble and insoluble extracts and of the DEAE-Sepharose CL-6B fractions of the soluble polysaccharide were determined. Three main types of polysaccharide families were solubilized. The major family was composed of sulfated glucuronorhamnoxyloglycans (ulvan) and was essentially extracted with oxalate. Two hemicellulosic fractions were also isolated and consisted of glucuronans and glucoxylans. Minor fractions consisting of sulfated polysaccharides containing glucose, xylose, mannose and protein were also isolated.