Algae. 1989; 4(2): 213-219.
Alginic Acid in Corallinaceae (Cryptonemiales, Rhodophyta)
Megumi Okazaki, Keiko Tazawa
Department of Biology, Tokyo Gakugei University
A calcium-binding substance (CaBS) was isolated from all species tested (nine species) in the family Corallinaceae (Cryptonemiales, Rhodophyta) and it was identified as alginic acid by infrared absorption spectrum and by analysis of sugar composition of its acid hydrolysate using thin layer chromatography and high pressure liquid chromatography. The average content of alginic acid was 1.3% (w/w) on a basis of organic matter of the fronds. On the other hand, CaBS or alginic acid was not detected in all non-coralline species tested (five species) of two families, Cryptonemiaceae and Gloiopeltidaceae (Cryptonemiales). These results suggest that occurrence of alginic acid in Rhodophyta might be restricted to species of Corallinaceae. The following species were used as materials: Serraticardia maxima, Calliarthron yessoense, Corallina pilulifera, C. squamata, Amphiroa zonata, A. fragilissima and Marginisporum crassissimum (Corallinoideae, Corallinaceae); Lithophyllum tortuosum and Lighothamnium erubescens (Melobesioideae, Corallinaceae); Carpopeltis angusta, C. divaricata, Pachymeniopsis lanceolata and Grateloupia carnosa (Cryptonemiaceae); Gloiopeltis furcata (Gloiopeltidaceae). Alginic acid in Corallinaceae seems to play an important role in formation of calcitic calcium carbonate in spite of the presence of Mg super(2+), a strong inducer of aragonite.
Keywords : alginic acid, calcification, calcite, calcium carbonate, corallinaceae