CHEMICAL COMPOSITION OF THE CELL WALLS OF THE FRESHWATER RED ALGA LEMANEA ANNULATA (BATRACHOSPERMALES)

Cell walls of the generic phase of the freshwater red alga Lemanea annulata Kuetz were mechanically isolated and chemically characterized. Walls consisted mainly of polysaccharide with lesser quantities of associated protein and lipid. The major wall component was alkali-soluble xylan, comprised mainly of 4-linked beta -xylopyranosyl residues and small amounts of 3-O-substituted beta -xylopyranosyl residues. Hot water extracts yielded non-sulfated polymers, with 3- or 3,4-linked beta -galactosyl residues alternating with 4-linked alpha -glucuronosyl residues as the predominant structural features. This acid polysaccharide shares many characteristics of the mucilage previously described from the freshwater genus Batrachospermum . Isolated cell walls of L. annulata contained approximately 6% cellulose.