scholarly journals DEVELOPMENT OF METHODS FOR OBTAINING POLYSACCHARIDES FROM BIRCH LEAVES (BETULA PENDU-LA ROTH., BETULA PUBESCENS EHRH.)

2019 ◽  
pp. 23-31
Author(s):  
Kseniya Igorevna Rovkina ◽  
Sergey Vladimirovich Krivoshchekov ◽  
Artem Mikhaylovich Guriev ◽  
Mekhman Suleyman ogly Yusubov ◽  
Mikhail Valer'yevich Belousov
Keyword(s):  
Molecular Weight ◽  
High Performance ◽  
Raw Materials ◽  
Gravimetric Method ◽  
Betula Pubescens ◽  
High Yield ◽  
Low Molecular Weight ◽  
Extraction Temperature ◽  
Extraction And Purification ◽  
Betula Pubescens Ehrh

The development of a complex technique for the extraction and purification of polysaccharides from birch leaves (Betula pendula Roth.,Betula pubescens Ehrh.) (PSfB) was the purpose of this study. The following characteristics were used as criteria for evaluating the effect of the parameters studied on the production of target substances: yield of PSfB (gravimetric method), protein content (spectrophotometric method), molecular weight distribution (high performance exclusion chromatography) and degree of purification from low molecular weight impurities (LMWI) (IR) spectroscopy).During the experiment, the optimal parameters were determined at various stages of obtaining the PSfB: degree of raw materials grinding – 1.2–3 mm, pH of the extractant (purified water with pH=7), the ratio of raw materials : extractant (1 : 20), extraction temperature (50 °C), temperature and degree of evaporation (50 °C; 4 times), the ratio of concentrate : ethanol (1 : 3) and the method of purification from the LMWI (ultrafiltration).The result of this work is an optimized method for obtaining PSfB, allowing to achieve high yield without loss of product quality (minimum allowable content of low molecular weight impurities with the highest content of high molecular weight fractions).This technique is the basis for the development of laboratory regulations for obtaining an active pharmaceutical substance based on polysaccharides from birch leaves.

scholarly journals Fractionation of lignosulphonates released during the early stages of delignification

1983 ◽  
Vol 61 (2) ◽  
pp. 416-420 ◽  
Author(s):  
Norman G. Lewis ◽  
David A. I. Goring ◽  
Alfred Wong
Keyword(s):  
Molecular Weight ◽  
High Performance ◽  
Black Spruce ◽  
Gel Permeation Chromatography ◽  
Bimodal Distribution ◽  
High Yield ◽  
Low Molecular Weight ◽  
Lower Yield ◽  
Spruce Wood ◽  
Gel Permeation

High-yield spent bisulphite liquor (HY-SBL) from sulphonated black spruce wood (Piceamariana) was fractionated by gel permeation chromatography (GPC) and by high-performance liquid chromatography (HPLC). The GPC fractionation gave a wide bimodal distribution, whereas with HPLC, a more detailed resolution was seen with the bulk of the fraction giving several clearly defined peaks. The paucidisperse material was further concentrated by a bulk fractionation of the crude SBL which included complexing the lignosulphonates with dicyclohexylamine. The isolated paucidisperse material was found to be dialyzable and to constitute 90% of the lignosulphonate in the sample of SBL. If the bisulphite pulp obtained was recooked in fresh acid sulphite liquor to a lower yield, most of the lignosulphonate dissolved was widely polydisperse with no indication of the discrete components resolvable by HPLC. However, 25% of the lignin made soluble was in the form of the paucidisperse fractions. In all, we were able to obtain about 50% of the lignin in spruce wood as a relatively low molecular weight lignosulphonate resolvable into discrete fractions by HPLC.

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

scholarly journals Composition of low-molecular-weight glutenin subunits in common wheat (Triticum aestivum L.) and their effects on the rheological properties of dough

2021 ◽  
Vol 16 (1) ◽  
pp. 641-652
Author(s):  
Sławomir Franaszek ◽  
Bolesław Salmanowicz
Keyword(s):  
Molecular Weight ◽  
Rheological Properties ◽  
Common Wheat ◽  
High Performance ◽  
Triticum Aestivum L ◽  
Quality Parameters ◽  
Low Molecular Weight ◽  
Wheat Varieties ◽  
Breeding Lines ◽  
Capillary Zone

Abstract The main purpose of this research was the identification and characterization of low-molecular-weight glutenin subunit (LMW-GS) composition in common wheat and the determination of the effect of these proteins on the rheological properties of dough. The use of capillary zone electrophoresis and reverse-phase high-performance liquid chromatography has made it possible to identify four alleles in the Glu-A3 and Glu-D3 loci and seven alleles in the Glu-B3 locus, encoding LMW-GSs in 70 varieties and breeding lines of wheat tested. To determine the technological quality of dough, analyses were performed at the microscale using a TA.XT Plus Texture Analyzer. Wheat varieties containing the Glu-3 loci scheme (Glu-A3b, Glu-A3f at the Glu-A3 locus; Glu-B3a, Glu-B3b, Glu-B3d, Glu-B3h at the Glu-B3 locus; Glu-D3a, Glu-D3c at the Glu-D3 locus) determined the most beneficial quality parameters.

scholarly journals Investigating Lignin-Derived Monomers and Oligomers in Low-Molecular-Weight Fractions Separated from Depolymerized Black Liquor Retentate by Membrane Filtration

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2887
Author(s):  
Kena Li ◽  
Jens Prothmann ◽  
Margareta Sandahl ◽  
Sara Blomberg ◽  
Charlotta Turner ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Performance ◽  
Membrane Filtration ◽  
Black Liquor ◽  
Complex Mixture ◽  
Value Added ◽  
Kraft Pulping ◽  
Classification Model ◽  
Low Molecular Weight ◽  
Chemical Complexity

Base-catalyzed depolymerization of black liquor retentate (BLR) from the kraft pulping process, followed by ultrafiltration, has been suggested as a means of obtaining low-molecular-weight (LMW) compounds. The chemical complexity of BLR, which consists of a mixture of softwood and hardwood lignin that has undergone several kinds of treatment, leads to a complex mixture of LMW compounds, making the separation of components for the formation of value-added chemicals more difficult. Identifying the phenolic compounds in the LMW fractions obtained under different depolymerization conditions is essential for the upgrading process. In this study, a state-of-the-art nontargeted analysis method using ultra-high-performance supercritical fluid chromatography coupled to high-resolution multiple-stage tandem mass spectrometry (UHPSFC/HRMSn) combined with a Kendrick mass defect-based classification model was applied to analyze the monomers and oligomers in the LMW fractions separated from BLR samples depolymerized at 170–210 °C. The most common phenolic compound types were dimers, followed by monomers. A second round of depolymerization yielded low amounts of monomers and dimers, while a high number of trimers were formed, thought to be the result of repolymerization.

Comparison of exopolysaccharides from mucoid and nonmucoid strains of Clavibacter michiganensis subspecies sepedonicus

1993 ◽  
Vol 39 (3) ◽  
pp. 291-296 ◽  
Author(s):  
Paul J. Henningson ◽  
Neil C. Gudmestad
Keyword(s):  
Molecular Weight ◽  
High Performance ◽  
Size Exclusion ◽  
Enzyme Linked Immunosorbent Assay ◽  
Low Molecular Weight ◽  
Neutral Sugar ◽  
Clavibacter Michiganensis ◽  
Serological Reaction ◽  
Molecular Weights ◽  
Exclusion Chromatography

The exopolysaccharides produced by six strains of Clavibacter michiganensis ssp. sepedonicus were isolated and purified by liquid chromatography. Neutral sugar composition and molecular weights were determined for each polysaccharide fraction, using gas chromatography and high-performance size-exclusion chromatography. The serological reaction of each fraction was tested using enzyme-linked immunosorbent assay. Exopolysaccharide from nonmucoid strains contained only low molecular weight polysaccharides (1.5 × 103 to 1.1 × 104). Exopolysaccharide from mucoid and intermediate strains could be separated into low (4.0 × 103 to 1.1 × 104) molecular weight and high (5.0 × 105 to 1.6 × 106) molecular weight fractions. High molecular weight polysaccharides were composed almost exclusively of galactose, glucose, and fucose. The ratios of these sugars were highly variable among strains. Low molecular weight polysaccharides were primarily composed of galactose with significant and varying amounts of glucose, rhamnose, mannose, and ribose. All polysaccharide fractions except one, produced by a nonmucoid strain, reacted in the immunoassay test.Key words: exopolysaccharide, polysaccharide, Clavibacter, michiganensis, sepedonicus.

Biodiesel fuel synthesis by interesterification of triglycerides with carboxylate esters of low molecular weight

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Egle Sendzikiene ◽  
Violeta Makareviciene
Keyword(s):  
Molecular Weight ◽  
Raw Materials ◽  
Fatty Acid Esters ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Transport Sector ◽  
Biodiesel Fuel ◽  
Low Molecular Weight ◽  
Raw Glycerol ◽  
Biodiesel Synthesis

Abstract The ever-increasing environmental pollution from greenhouse gases motivates the search for methods to reduce it. One such method is the use of biodiesel fuels in the transport sector. Conventional biodiesel production generates up to 10% of a by-product, raw glycerol, whose amount continues to increase as biodiesel production volumes expand, but its demand remains limited. Recently, options have been analysed to replace the triglyceride transesterification process generally used in biodiesel production with an interesterification process that does not generate raw glycerol, instead yielding triacylglycerol that can be directly used as fuel for diesel engines by mixing with fatty acid esters. Additionally, triacylglycerol improves the low-temperature properties of fuel. The present article discusses triglyceride interesterification processes using various carboxylate esters of low molecular weight. Information is provided on raw materials that can be subjected to interesterification for biodiesel synthesis. The possible applications of chemical and enzymatic catalysis for triglyceride interesterification are discussed, and the influence of the catalyst amount, molar ratio of reactants, temperature and process duration on the effectiveness of interesterification is examined. The conditions and effectiveness of noncatalytic interesterification are also discussed in the article. Qualitative indicators of the products obtained and their conformity to the requirements of the European standard for biodiesel fuel are discussed.

scholarly journals Determination of 11 Low-Molecular-Weight Carbonyl Compounds in Marine Algae by High-Performance Liquid Chromatography

2006 ◽  
Vol 44 (5) ◽  
pp. 233-238 ◽  
Author(s):  
V. M. da Silva ◽  
M. C. da Cunha Veloso ◽  
E. T. Sousa ◽  
G. Vieira Santos ◽  
M. C. Accioly ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Carbonyl Compounds ◽  
High Performance ◽  
Marine Algae ◽  
Low Molecular Weight
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