Structure of some sulfated sugars isolated after acid hydrolysis of the extracellular polysaccharide of Porphyridium sp., a unicellular red alga

1991 ◽  
Vol 210 ◽  
pp. 349-352 ◽  
Author(s):  
Niculina Lupescu ◽  
Shoshana (Malis) Arad ◽  
Shimona Geresh ◽  
Michael A. Bernstein ◽  
Robert Glaser
1962 ◽  
Vol 40 (12) ◽  
pp. 2204-2213 ◽  
Author(s):  
A. Misaki ◽  
S. Kirkwood ◽  
J. V. Scaletti ◽  
F. Smith

The extracellular polysaccharide isolated from cultures of Xanthomonas oryzae is composed of D-glucose (5 molecular proportions), D-glucuronic acid (2 molecular proportions), and D-mannose (5 molecular proportions). Acid hydrolysis of this polysaccharide, which contains 0.3% combined pyruvic acid, yields 2-O-β-D-glucopyranosyluronic acid D-mannose, which has been characterized as its crystalline fully methylated β-glycoside. Hydrolysis of the methylated polysaccharide gives 2,3,4,6-tetra-O-methyl-D-mannose (3 molecular proportions), 2,3,4-tri-O-methyl-D-glucuronic acid (1 molecular proportion), 2,3,6-tri-O-methyl-D-glucose (4 molecular proportions), 3,4,6-tri-O-methyl-D-mannose (2 molecular proportions), 2,6-di-O-methyl-D-glucose (3 molecular proportions), 2,3-di-O-methyl-D-glucose (1 molecular proportion). The polyalcohol derived from the polysaccharide by periodate oxidation followed by sodium borohydride reduction gives upon acid hydrolysis glycerol (2 molecular proportions), erythritol (1 molecular proportion), and D-glucose (1 molecular proportion). The general structural significance of these findings is discussed.


1976 ◽  
Vol 155 (1) ◽  
pp. 181-185 ◽  
Author(s):  
J H Kieras ◽  
F J Kieras ◽  
D V Bowen

Acid hydrolysis of the extracellular polysaccharide of Porphyridium cruentum (a unicellular red alga) produced a mixture of aldobiuronic acids and free hexuronic acids. Fractionation of this mixture on an ion-exchange column yielded a hexuronic acid characterized as the title compound. Its identity was confirmed by chromatographic comparisons with the authentic compound, by reduction to the corresponding methylated aldose, by resistance to controlled lead tetra-acetate oxidation and by chemical-ionization mass spectrometry. Complete spectra have been deposited as Supplementary Publication SUP50062 (7 pages) with the British Library (Lending Division), Boston Spa, Wetherby, W. Yorkshire LS23 7BQ, U.K., from whom copies may be obtained under the terms given in Biochem. J. (1976) 153, 5.


1961 ◽  
Vol 39 (11) ◽  
pp. 2274-2281 ◽  
Author(s):  
P. A. J. Gorin ◽  
J. F. T. Spencer

The extracellular polysaccharide of Corynebacteriuminsidiosum, the causative agent of alfalfa wilt, contains D-glucose, D-galactose, and L-fucose in the proportions 2:3:4, with smaller amounts of an unknown acid. Partial acid hydrolysis of the polysaccharide gives 4-O-β-D-glucopyranosyl-L-fucose and 4-O-β-D-glucopyranosyl-(3-O-D-galactopyranosyl)-L-fucose as neutral oligosaccharides. Also formed are D-galactose, substituted in the 4-position with an unknown acid, and 4-O-β-D-glucopyranosyl-(3-O-D-galactopyranosyl)-L-fucose, which has the 4-position of the galactopyranosyl moiety substituted in a similar way. It appears that the above oligosaccharides represent the structure of the polysaccharide to a considerable extent.


1962 ◽  
Vol 41 (2) ◽  
pp. 234-246 ◽  
Author(s):  
H. J. van der Molen

ABSTRACT A procedure for the quantitative determination of 5β-pregnan-3α-ol-20-one in urine is described. After acid hydrolysis of the pregnanolone-conjugates in urine, the free steroids are extracted with toluene. Pregnanolone is isolated in a pure form as its acetate; after chromatographic separation of the free steroids on alumina, the fraction containing pregnanolone is acetylated and rechromatographed on alumina. Quantitative determination of the isolated pregnanolone-acetate is carried out with the aid of the infrared spectrum recorded by a micro KBr-wafermethod. The reliability of the method under various conditions is discussed under the headings, specificity, accuracy, precision and sensitivity. It is possible to determine 30–40 μg pregnanolone in a 24-hours urine portion with a precision of 25%.


Author(s):  
M. Alekseenko ◽  
V. Litvyak ◽  
A. Sysa ◽  
E. Hrabovska ◽  
O. Galenko

2012 ◽  
Vol 11 (12) ◽  
pp. 2313-2318
Author(s):  
Theodor Malutan ◽  
Adina Elena Panzariu

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Alberto Palma ◽  
Javier Mauricio Loaiza ◽  
Manuel J. Díaz ◽  
Juan Carlos García ◽  
Inmaculada Giráldez ◽  
...  

Abstract Background Burning fast-growing trees for energy production can be an effective alternative to coal combustion. Thus, lignocellulosic material, which can be used to obtain chemicals with a high added value, is highly abundant, easily renewed and usually inexpensive. In this work, hemicellulose extraction by acid hydrolysis of plant biomass from three different crops (Chamaecytisus proliferus, Leucaena diversifolia and Paulownia trihybrid) was modelled and the resulting solid residues were used for energy production. Results The influence of the nature of the lignocellulosic raw material and the operating conditions used to extract the hemicellulose fraction on the heat capacity and activation energy of the subsequent combustion process was examined. The heat power and the activation energy of the combustion process were found to depend markedly on the hemicellulose content of the raw material. Thus, a low content in hemicelluloses resulted in a lower increased energy yield after acid hydrolysis stage. The process was also influenced by the operating conditions of the acid hydrolysis treatment, which increased the gross calorific value (GCV) of the solid residue by 0.6–9.7% relative to the starting material. In addition, the activation energy of combustion of the acid hydrolysis residues from Chamaecytisus proliferus (Tagasaste) and Paulownia trihybrid (Paulownia) was considerably lower than that for the starting materials, the difference increasing with increasing degree of conversion as well as with increasing temperature and acid concentration in the acid hydrolysis. The activation energy of combustion of the solid residues from acid hydrolysis of tagasaste and paulownia decreased markedly with increasing degree of conversion, and also with increasing temperature and acid concentration in the acid hydrolysis treatment. No similar trend was observed in Leucaena diversifolia (Leucaena) owing to its low content in hemicelluloses. Conclusions Acid hydrolysis of tagasaste, leucaena and paulownia provided a valorizable liquor containing a large amount of hemicelluloses and a solid residue with an increased heat power amenable to efficient valorization by combustion. There are many potential applications of the hemicelluloses-rich and lignin-rich fraction, for example as multi-components of bio-based feedstocks for 3D printing, for energy and other value-added chemicals.


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