Mannan groups

Biosorption is a rather complex process affected by several factors that include different binding mechanisms (Figure 10.4). Most of the functional groups responsible for metal binding are found in cell walls and include carboxyl, hydroxyl, sulfate, sulfhydryl, phosphate, amino, amide, imine, and imidazol moieties.4 90 The cell wall of plant biomass has proteins, lipids, carbohydrate polymers (cellulose, xylane, mannan, etc.), and inorganic ions of Ca(II), Mg(II), and so on. The carboxylic and phosphate groups in the cell wall are the main acidic functional groups that affect directly the adsorption capacity of the biomass.101... 

Fungus A general term to denote a group of eukaryotic protist, including mushrooms, yeasts, rusts, molds, smuts, etc., which are characterized by the absence of a rigid cell wall composed of chitin, mannans, and sometimes cellulose. 

At high temperatures, the Tj values of 13C nuclei of polysaccharides may be sufficiently long to create difficulties in quantitative estimation of integral intensities. Values have been observed, at 25.2 MHz, of 0.27-0.31 s [C-l-C-5 of a-D-(l—>6)-linked D-mannopyranan at 90°], and, for side chains of branched-chain mannans, of 0.22 s [C-l of a-D-mannopyranosyl groups linked (1—>2) to a main chain of (1—>6)-linked-D-mannopyranosyl residues at90°] and of 0.31 s [C-l atoms of2-0-sub-stituted /3-D-mannopyranosyl side-chain units linked (1—>2) to a similar main-chain, at 70°]. Under such conditions, the n.O.e. values are57... 

The majority of ascomycetous yeasts form cell-wall mannans or ga-lactomannans having main chains of (1— 6)-linked a-D-mannopyrano-syl residues, often substituted at 0-2 by a-linked glycosyl groups. The linkage types in the rest of the side chains vary widely, and can consist of 2-O-substituted a- or /3-D-mannopyranosyl residues, or 3-O-substi-... 

Lamellar, single crystals of ivory-nut mannan were studied by electron diffraction. The base-plane dimensions of the unit cell are a = 0.722 nm and b = 0.892 nm. The systematic absences confirmed the space group P212121. The diffraction pattern did not change with the crystallization temperature. Oriented crystallization ofD-mannan with its chain axis parallel to the microfibril substrates, Valonia ventricosa and bacterial cellulose, was discovered ( hetero-shish-kebabs ). 

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