A new fractionation method for kappa- and lambda-carrageenans isolated from Gigartina pistillata (Rhodophyta)

Gigartina pistillata (GMELIN) STACKHOUSE harvested commercially along the Atlantic coast of Morocco is generally a mixture of gametophytes with a cell wall enriched in κ-carrageenan, and tetrasporophytes with a wall composed mainly of λ-carrageenan. In order to separate both polysaccharides, two extraction methods were investigated. The first one involved sequential extraction in water with increasing temperatures in 20 °C increments starting from 20 °C up to 100 °C. The second method was carried out by using successive ethanol concentrations (100, 80, 60, 40, 20 % and water). Chemical characterization of the different fractions revealed that low extraction temperatures or high ethanol concentrations contained mainly the κ-carrageenan. In contrast, high extraction temperatures or low ethanol concentrations yielded λ-carrageenan enriched fractions. These results demonstrate that the use of these distinct methods can selectively extract κ- or λ-carrageenans to improve the quality of the final carrageenan product and increase the value of raw algal material in Morocco.

Aziza Mouradi (1) , Abdellah Amimi (1) , Jean Claude Mollet (2) , Thierry Givernaud

1 UIT - Université Ibn Tofaïl
2 UA - Université d'Artois

Domains: Life Sciences [q-bio]; Biochemistry, Molecular Biology; Biochemistry [q-bio.BM]; Chemical Sciences; Polymers; Life Sciences [q-bio]; Life Sciences [q-bio]; Vegetal Biology

Aziza Mouradi, Abdellah Amimi, Jean Claude Mollet, Thierry Givernaud. A new fractionation method for kappa- and lambda-carrageenans isolated from Gigartina pistillata (Rhodophyta). Algological Studies, 2006, 122 (1), pp.107-122. ⟨10.1127/1864-1318/2006/0122-0107⟩. ⟨hal-02121541⟩