Korn
Jan 7th, 2008, 02:30 PM
http://www.nzetc.org/tm/scholarly/tei-Bio14Tuat01-t1-body-d5.html
With food seaweeds, the really interesting member of the B group is vitamin B12; and it would help now to recall the analytical figures and concentration factors quoted earlier for cobalt, since this element is the inorganic constituent of vitamin B12. Provasoli has summarized the figures for the vitamin B12 content of various seaweeds published by several groups of research workers. The following are high in this vitamin:
Red: Acanthopeltis japonica
Ceramium rubrum
Ceramium tenuicorne
Gelidium amansii
Laurentia pinnatifida
Polysiphonia brodiaei
Rhodomela subfusca
Green: Enteromorpha intestinalis
Brown: Alaria esculenta
Hymenthalia elongata
Laminaria digitata
Laminaria hyperborea
Apparently green seaweeds contain more than red, and both are higher than brown. It has been shown that some algae can accumulate cobalt to the remarkable extent of producing a concentration factor of 10,000 (Ericson). The origin of the B12 is bacterial — due either to the presence on the algae of epiphytic bacteria which synthesize this vitamin or to the occurrence of these bacteria in the surrounding sea-water. In either case the vitamin is taken up by the seaweed and accumulation occurs. ‘Bacteria from algae which were poor in vitamin B12, generally produce small amounts of B12, while bacteria from vitamin B12-rich algae formed larger quantities of the vitamin’ (Lundin and Ericson). These authors also suggested that red and green seaweeds may have higher B12 contents than brown because the former ‘often have greater surface areas per gram dry weight than the brown algae.’
With food seaweeds, the really interesting member of the B group is vitamin B12; and it would help now to recall the analytical figures and concentration factors quoted earlier for cobalt, since this element is the inorganic constituent of vitamin B12. Provasoli has summarized the figures for the vitamin B12 content of various seaweeds published by several groups of research workers. The following are high in this vitamin:
Red: Acanthopeltis japonica
Ceramium rubrum
Ceramium tenuicorne
Gelidium amansii
Laurentia pinnatifida
Polysiphonia brodiaei
Rhodomela subfusca
Green: Enteromorpha intestinalis
Brown: Alaria esculenta
Hymenthalia elongata
Laminaria digitata
Laminaria hyperborea
Apparently green seaweeds contain more than red, and both are higher than brown. It has been shown that some algae can accumulate cobalt to the remarkable extent of producing a concentration factor of 10,000 (Ericson). The origin of the B12 is bacterial — due either to the presence on the algae of epiphytic bacteria which synthesize this vitamin or to the occurrence of these bacteria in the surrounding sea-water. In either case the vitamin is taken up by the seaweed and accumulation occurs. ‘Bacteria from algae which were poor in vitamin B12, generally produce small amounts of B12, while bacteria from vitamin B12-rich algae formed larger quantities of the vitamin’ (Lundin and Ericson). These authors also suggested that red and green seaweeds may have higher B12 contents than brown because the former ‘often have greater surface areas per gram dry weight than the brown algae.’