Isolation and characterizartion of alginic acid from commercially culturedNemacystus decipiens (Itomozuku)

An alginate was isolated from commercially cultured Nemacystus decipiens wh ich had been harvested in Yonashiro Town (Okinawa, Japan). The yield of the alginate was 1.6% (w/w of wet alga), and the uronic acid, ash and moisture contents of the alginate were 86.0%, 12.0%, and 2.3% (w/w). respectively. The molecular mass of the alginate was estimated to be about 1.5 x 10(5). T he infrared spectrum and optical rotation of the alginate mere in agreement with those of the standard alginate, D-Mannuronic acid and L-guluronic aci d were identified by H-1- and C-13-NMR spectroscopy, the molar ratio of bot h sugar residues being estimated to be 0.72:1.00.