The Polysaccharidic Nature of the Skeleton of Marennine as Determined by NMR Spectroscopy.

The water-soluble blue-green pigment marennine, produced and partly excreted by the diatom Haslea ostrearia, and known for a long time for its role in the greening of oysters, was isolated from the culture medium, purified, and analyzed by Nuclear Magnetic Resonance (NMR) in order to gain insight into its chemical structure. The spectra show mainly carbohydrates of a complex composition, apparently highly branched, and with a mass in the order of 10 kDa. There are, in addition, some signals of aliphatic and, much weaker, aromatic groups that present aglycons. The latter might be responsible for the color. These carbohydrates are always associated with the blue-green color and cannot be separated from it by most treatments; they are interpreted as constituting the frame of the pigment. NMR after hydrolysis identifies the most abundant monosaccharides in marennine as galactose, xylose, mannose, rhamnose, and fucose.

Use of palm (Poenix dactilyfera L.) fiber and sewage sludge co compost as substrates in soilless crop system.

The Co-Compostage (CC) of Palm (Poenix dactylifera L.) Fiber (PF) and Sewage Sludge (SS) at volume rate (1PF/1SS), mixed with Top Soil (TS) have been used as a substrate for cucumber cultivated in soilless crop system. Five substrates with volume ratio T (CC-TS) were tested: T (10-0), T (9-1), T (8-2), T (7-3) and T (6-4). They were compared to peat in nursery and to TS in Cucumis sativus L. crop production. Total porosity, bulk density, moisture content, rate of drainage, pH and electritical conductivity of T (8-2) and T (7-3) were relatively favorable for plant growth. After 45 days of growth and in comparison to peat, T (9-1), T (8-2) and T (7-3) gave the best parameters of root development: volume, architecture, length, number, best seedling growth and a positive correlation (R = 0.751) between root and shoot dry matter. After 120 days, cucumber attained the best root development under T (8-2) and T (7-3). Fruits production of these substrates was 40% higher than those of the control.