P-Mannan

There is no information so far available about mannan degrading enzymes of alkaliphiles. In this paper, a P-mannan degrading alkaliphile Bacillus sp. AM-001) with high productivities of cell-associated P-mannosidase and three extracellular P-... 

These properties of the enzyme are good for the production of D-mannose from P-mannan in the presence of the P-mannanase described above. 

Using Py-FI MS, even better results were obtained [3] for the differentiation of the type of bonds. Using oven pyrolysis at 500° C and evaporation of the sample in the MS source, different spectra were generated from 1,3-a-mannan, 1,3-p-mannan, 1,4-p-mannan, 1,2-a-mannan [3], and are shown in Figures 7.1.11 (A) to 7.1.11 (D). 

P-Mannan is water-insoluble and solubilizing it requires very strong alkali, cuprammonium or derivatization. X-ray and electron diffraction show that mannan has a ribbon-like conformation, similar to cellulose, with the 2-OH axial instead of equatorial. In seeds (palm, coffee, caraway) a few (<5%) of a-Gal groups are attached to the hydroxymethyl and in seaweeds a small percentage (<5) of Glc residues may occur in the chain. A pure P(l-4) mannan has been extracted from cell walls of the siphonous green alga Codium latum as the methylol mannan with paraformaldehyde dimethylsulphoxide. It was purified by size exclusion chromatography in dimethyl sulphoxide and recovered by the addition of water or methanol and could be re-dissolved in hot dimethyl sulphoxide. Infra-red and n.m.r. spectroscopy and periodate oxidation confirmed the unbranched P(l-4) structure [185]. 

P-mannans (47). The most extensive structural investigations were carried out on the mannan from the best producer, R. glutinis. An alternating arrangement of 3-(1 3)- and 3-(1 4)-linked residues was deduced from methylation analysis and characterization of di-and trisaccharides liberated by partial acid hydrolysis. Crystalline 4-0-3-g-mannopyranosyl-g-mannose was isolated in 67% yield. 

Scheme 7. The sulfoxide method for glycoside bond formation (a) and its application (b) to the synthesis of a hexasaccharide p-mannan found in bacterial antigens (35). (Crich, 2001 ) ...

Scheme 8.9). The C NMR and optical rotation of trisaccharide 26 were identical to those reported by Lichtenthaler (vide supra) [36]. Crich and co-workers have also successfully applied their methodology towards the synthesis of complex P-mannan structures [48] and the mannosyl erythritol lipid MEL A [49]. 

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