A comparative investigation on the water-soluble and the alkali-soluble alginates from various Japanese brown algae.

The yields and the M/G ratios of water-soluble alginates (WSA) from various brown algal sources in Japan were investigated and were compared with those of alginates extracted with alkali in the routine procedures(ASA). The yields on a dry weight basis of WSA from most brown algae varied widely from 0.01% (Sargassum thunergii) to 9.23% (Laminaria religiosa) while those of ASA varied to lesser extentsuch as from 2.20% (Hizikia fusiformis) to 31.80% (Sargassum kjellmanianum)in most samples. The M/G ratios of these alginates measured by high performance liquidc hromatography fluctuated between O.66 (Sargassum kjellmanianum) and 5.28 (Sargassum patens)with WSA while they were O.26 (Sargassum ringgoldianum) to 1.78 (Laminaria religiosa) with ASA. However, higher M/G ratios were found for WSA than those for ASA in any individual brown alga tested.