Structure of the extracellular bacterial polysaccharide from Arthrobacter viscosus NRRL B-1973

1968 ◽  
Vol 46 (21) ◽  
pp. 3353-3361 ◽  
Author(s):  
J. H. Sloneker ◽  
Danute G. Orentas ◽  
C. A. Knutson ◽  
P. R. Watson ◽  
Allene Jeanes
Keyword(s):  
Acid Hydrolysis ◽  
Linear Structure ◽  
Sugar Residue ◽  
Hydroxyl Groups ◽  
Bacterial Polysaccharide ◽  
Sodium Metaperiodate ◽  
Mannuronic Acid ◽  
Arthrobacter Viscosus ◽  
Hydrolysis Of

D-Glucose, D-galactose, and D-mannuronic acid in equimolar proportions constitute 75% of the weight of the polysaccharide elaborated by Arthrobacter viscosus NRRL B-1973. O-Acetyl groups account for the remaining 25% of the weight; 50% of the hydroxyl groups are acetylated. Acid hydrolysis of the polysaccharide revealed that the D-mannopyranosyluronic acid bonds hydrolyzed with unexpected ease. Controlled acid hydrolysis afforded three oligosaccharides identified as 4-O-β-D-glucopyranosyl-D-galactose; 4-O-β-D-mannopyranosyluronic acid-D-glucose; and O-β-D-mannopyranosyluronic acid-(1 → 4)-O-β-D-glucopyranosyl-(1 → 4)-D-galactose. The native polysaccharide was oxidized slowly by sodium metaperiodate and consumed 0.42 mole per sugar residue in 340 h at 4°. The deacetylated polysaccharide consumed 0.67 mole of periodate per sugar residue and produced 1 mole of acid per 160 to 165 sugar residues in 170 h at 4°. At 20° the deacetylated polysaccharide was oxidized excessively by periodate, 1.5 moles of oxidant was consumed, and 0.4 mole of acid was produced per sugar residue in 340 h. However, only 20% of the C4-substituted D-glucose residues in the polysaccharide was cleaved by periodate in spite of the excessive oxidation at 20°.The polysaccharide has a linear structure and consists predominantly of repeating trisaccharide units, O-β-D-mannopyranosyluronic acid-(1 → 4)-O-β-D-glucopyranosyl-(1 → 4)-D-galactose.

Studies on the lignin of Eucalyptus regnans F. Muell. VII. The acid hydrolysis of ethanyol lignin-A

1953 ◽  
Vol 6 (2) ◽  
pp. 156 ◽  
Author(s):  
JWT Merewether
Keyword(s):  
Hydrochloric Acid ◽  
Acid Hydrolysis ◽  
Carbonyl Group ◽  
Dilute Hydrochloric Acid ◽  
Hydroxyl Groups ◽  
Eucalyptus Regnans ◽  
Ethoxyl Group ◽  
Hydrolysis Of

Ethanol lignin-A from the ethanolysis of Eucalyptus regnans P. Muell. has been hydrolysed with dilute hydrochloric acid with the object of ascertaining whether the combined ethoxyl is present as an acetal or as ether. Hydrolysis with 12 per cent. hydrochloric acid was found to split off one ethoxyl group, while hydrolysis with 20 per cent. acid brought about complete de-ethylation. The de-ethylated ethanol lignin-A contained one carbonyl group less and two hydroxyl groups more than the original ethanol lignin-A. These results lend no support to the hypothesis that alcohol lignins are acetals, and favour the theory that the combined alkoxyl is probably present as ether.

THE STRUCTURE AND RESISTANCE TO METHYLATION OF 1,2-β-GLUCANS FROM SPECIES OF AGROBACTERIA

1961 ◽  
Vol 39 (5) ◽  
pp. 1067-1073 ◽  
Author(s):  
P. A. J. Gorin ◽  
J. F. T. Spencer ◽  
D. W. S. Westlake
Keyword(s):  
Plant Pathogens ◽  
Dimethyl Sulphate ◽  
Linear Structure ◽  
Extracellular Polysaccharides ◽  
Dimethyl Formamide ◽  
Hydroxyl Groups ◽  
Partial Acid Hydrolysis ◽  
Sodium Borohydride Reduction ◽  
Chain Lengths ◽  
Hydrolysis Of

The structures of extracellular polysaccharides produced by the plant pathogens Agrobacterium tumefaciens (2 strains), A. rhizogenes, A. radiobacter, A. ruhi, A. gypsophilae, and A. pseudotsugae were investigated. Polymeric material was formed in good yield from all organisms except A. gypsophilae. Periodate oxidations of the polysaccharides and their sodium borohydride reduction products indicated linear 1,2-glucopyranose structures for A. tumefaciens (2 strains), A. rhizogenes, A. radiobacter, and A. rubi polymers. Optical rotational considerations led to the assignment of β-configurations. The linear structure for the A. radiobacter polysaccharide was confirmed by the isolation, after partial acid hydrolysis, of five 1,2-linked oligosaccharides with chain lengths of two to six. Periodate and chromatographic data indicated that the polysaccharide from A. pseudotsugae contained glucose and galactose and 1,6- as well as 1,2-glycopyranose links. It is noteworthy that the polysaccharides from the genus Agrobacteriurm are shown to be mainly 1,2-β-glucans, a structure not yet found in other genera.Treatment of linear 1,2-β-glucans from A. tumefaciens, A. radiobacter, and A. rhizogenes with sodium hydroxide – dimethyl sulphate, followed by silver oxide in methyl iodide dimethyl formamide, did not cause full methylation. Some of the 3-hydroxyl groups were not substituted and possible reasons for this unreactivity are discussed.

Bleaching ability of pre-hydrolyzed pulps in the context of a biorefinery mill

TAPPI Journal ◽  
2013 ◽  
Vol 12 (11) ◽  
pp. 49-53 ◽  
Author(s):  
CHRISTINE CHIRAT ◽  
LUCIE BOIRON ◽  
DOMINIQUE LACHENAL
Keyword(s):  
Carbon Content ◽  
Acid Hydrolysis ◽  
13C Nmr ◽  
Kraft Lignin ◽  
Kappa Number ◽  
Hydroxyl Groups ◽  
Kraft Pulps ◽  
Quaternary Carbon ◽  
Oxygen Delignification

Autohydrolysis and acid hydrolysis treatments were applied on mixed softwood chips. The cooking ability was studied by varying the alkali and duration of the cook. Pulps with kappa numbers varying from 30 to 70 were obtained. The bleaching ability of these pulps was studied and compared to control kraft pulps. The prehydrolyzed pulps were shown to be more efficiently delignified by oxygen than the control kraft pulps starting from the same kappa number. Furthermore, the final bleaching was also easier for these pulps. It was also shown that extensive oxygen delignification applied on high-kappa pre-hydrolyzed pulps could be a way to improve the overall yield, which is a prerequisite for the development of such biorefinery concepts. Lignin was isolated from the control kraft and the two pre-hydrolyzed kraft pulps and analyzed by 13C NMR. Lignins from pre-hydrolyzed kraft pulps had similar free phenolic groups content to the control kraft lignin, but their aliphatic hydroxyl groups and β-O-4 content were lower than for the control lignin. The quaternary carbon content was the same for all the samples.

DETERMINATION OF MICRO-AMOUNTS OF 5β-PREGNAN-3α-OL-20-ONE IN URINE USING INFRARED-SPECTROMETRY

1962 ◽  
Vol 41 (2) ◽  
pp. 234-246 ◽  
Author(s):  
H. J. van der Molen
Keyword(s):  
Infrared Spectrum ◽  
Quantitative Determination ◽  
Acid Hydrolysis ◽  
Chromatographic Separation ◽  
Pure Form ◽  
Infrared Spectrometry ◽  
Hydrolysis Of

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%.

Optimization of technological modes of cold acid hydrolysis of potato starch

2020 ◽  
Vol 26 (3) ◽  
pp. 222-233
Author(s):  
M. Alekseenko ◽  
V. Litvyak ◽  
A. Sysa ◽  
E. Hrabovska ◽  
O. Galenko
Keyword(s):  
Acid Hydrolysis ◽  
Potato Starch ◽  
Hydrolysis Of

FLOWTHROUGH ACID HYDROLYSIS OF RAPESEED STALKS

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

scholarly journals Tagasaste, leucaena and paulownia: three industrial crops for energy and hemicelluloses production

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Alberto Palma ◽  
Javier Mauricio Loaiza ◽  
Manuel J. Díaz ◽  
Juan Carlos García ◽  
Inmaculada Giráldez ◽  
...  
Keyword(s):  
Activation Energy ◽  
Acid Hydrolysis ◽  
Energy Production ◽  
Combustion Process ◽  
Operating Conditions ◽  
Raw Material ◽  
Energy Of Combustion ◽  
Increasing Temperature ◽  
Hydrolysis Of ◽  
Chamaecytisus Proliferus

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.

Sign in / Sign up

Export Citation Format

Share Document