Fractional isolation and structural characterisation of hemicellulosic polymers from delignified and ultrasonic irradiated sugarcane bagasse

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Jui-Li Ren ◽  
Zeng-Chao Geng ◽  
Chan-Fu Liu ◽  
Feng Xu ◽  
Jin-Xia Sun ◽  
...  
Keyword(s):  
Sugarcane Bagasse ◽  
Glucuronic Acid ◽  
Structural Studies ◽  
Sugar Composition ◽  
Total Sugars ◽  
Structural Characterisation ◽  
Molecular Weights ◽  
Second Stage ◽  
Total Dissolution ◽  
C Nmr

AbstractHemicellulose-type polysaccharides were isolated from the delignified and ultrasonic irradiated sugarcane bagasse by a sequential two-step alkaline extraction. It was found that the successive extractions with 15% and 18% KOH for 2 h, 15% and 18% NaOH for 2 h, 8% and 10% KOH for 15 h, and with 8% and 10% NaOH for 15 h resulted in a total dissolution of 89.6%, 92.8%, 94.9%, and 97.3% of the original hemicelluloses, respectively. Sugar analysis revealed that xylose was the predominant sugar composition of all the hemicelluloses, comprising 57.4- 68.6% of the total sugars. Arabinose (12.3-18.4%) and glucose (10.8- 14.6%) appeared as the second and third major sugar constituents. Galactose (3.9-8.7%), uronic acids, mainly 4-O-methyl-glucuronic acid (2.7-5.8%), rhamnose (1.2-2.6%), and mannose (0.2-1.3%) were observed as minor constituents. The structural studies by 13C-NMR spectroscopy showed that L-arabino (4-O-methyl-D-glucurono) xylans were the major constituents of the hemicellulosic polymers. Furthermore, the current results also showed that the four alkali-soluble hemicellulosic fractions, isolated during the first step treatment with relatively lower concentrations of alkalis, were more branched and acidic, and had larger molecular weights (Mw, 23100-34500), but lower thermal stability than the other four alkali-soluble hemicellulosic preparations (Mw, 21700-28700), extracted during the second stage treatment with relatively higher concentrations of alkalis.

THE EXTRACTION OF ORGANIC MATTER FROM SELECTED SOILS AND PARTICLE SIZE FRACTIONS WITH 0.5 M NaOH AND 0.1 M Na4P2O7 SOLUTIONS

1989 ◽  
Vol 69 (2) ◽  
pp. 253-262 ◽  
Author(s):  
M. SCHNITZER ◽  
P. SCHUPPLI
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Humic Acids ◽  
Nmr Spectra ◽  
Attractive Alternative ◽  
Particle Size Fractions ◽  
Molecular Weights ◽  
Naoh Solution ◽  
C Nmr ◽  
Medium Silt

Organic matter (OM) in the Bainsville and Melfort soils, and in coarse clay and medium silt fractions separated from these soils, was extracted under N2 with 0.5 M NaOH and unadjusted 0.1 M Na4P2O7 solutions. pH ranges of the soils and fractions in contact for 24 h with 0.5 M NaOH and 0.1 M Na4P2O7 solutions extended from 12.2 to 12.6 and 9.0 to 9.4, respectively. Slightly greater proportions of the soil-carbon were extracted by 0.5 M NaOH than by 0.1 M Na4P2O7 solution. The differences, however, did not appear to be significant and may vary from soil to soil. The efficiency of extraction and the characteristics of the extracted materials were assessed on humic acids (HAs), which were isolated from the extracts. From the Bainsville soil and fractions, 0.1 M Na4P2O7 solution extracted more high-molecular weight and more deeply colored HAs than did 0.5 M NaOH solution. But HAs extracted from the Melfort soil and fractions had similar molecular weights and colours. 13C NMR spectra showed that HAs extracted by 0.1 M Na4P2O7 solution tended to be more aromatic than HAs extracted by 0.5 M NaOH solution. Well defined solid-state 13C NMR spectra of HAs, containing up to 69.0% ash, could be recorded. Unadjusted 0.1 M Na4P2O7 solution under N2 was found to be an attractive alternative to 0.5 M NaOH solution as an extractant for soil OM. Key words: Humic acids, E4:E6 ratios, IR spectra, 13C NMR spectra, aromaticity

scholarly journals Physicochemical Characterization, Antioxidant and Immunostimulatory Activities of Sulfated Polysaccharides Extracted from Ascophyllum nodosum

Molecules ◽  
2018 ◽  
Vol 23 (8) ◽  
pp. 1912 ◽  
Author(s):  
Ligen Chen ◽  
Yan Wang ◽  
Hui Yang ◽  
Han Li ◽  
Wei Xu ◽  
...  
Keyword(s):  
Glucuronic Acid ◽  
Physicochemical Characterization ◽  
Ascophyllum Nodosum ◽  
Food Supplement ◽  
Raw Material ◽  
Sulfated Polysaccharides ◽  
Extraction Temperature ◽  
Molecular Weights ◽  
Extraction Solvent ◽  
Fast Flow

Polysaccharides from Ascophyllum nodosum (AnPS) were extracted and purified via an optimized protocol. The optimal extraction conditions were as follows: extraction time of 4.3 h, extraction temperature of 84 °C and ratio (v/w, mL/g) of extraction solvent (water) to raw material of 27. The resulting yield was 9.15 ± 0.23% of crude AnPS. Two fractions, named AnP1-1 and AnP2-1 with molecular weights of 165.92 KDa and 370.68 KDa, were separated from the crude AnPS by chromatography in DEAE Sepharose Fast Flow and Sephacryl S-300, respectively. AnP1-1 was composed of mannose, ribose, glucuronic acid, glucose and fucose, and AnP2-1 was composed of mannose, glucuronic acid, galactose and fucose. AnPS, AnP1-1 and AnP2-1 exhibited high scavenging activities against ABTS radical and superoxide radical, and showed protective effect on H2O2-induced oxidative injury in RAW264.7 cells. Furthermore, the immunostimulatory activities of AnP1-1 and AnP2-1 were evaluated by Caco-2 cells, the results showed both AnP1-1 and AnP2-1 could significantly promote the production of immune reactive molecules such as interleukin (IL)-8, IL-1β, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α. Therefore, the results suggest that AnPS and its two fractions may be explored as a potential functional food supplement.

Structural studies of digitoxin and related cardenolides by two-dimensional NMR

1990 ◽  
Vol 68 (2) ◽  
pp. 272-277 ◽  
Author(s):  
Torbjörn Drakenberg ◽  
Peter Brodelius ◽  
Deane D. McIntyre ◽  
Hans J Vogel
Keyword(s):  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Chair Conformation ◽  
Coupling Constants ◽  
Two Dimensional ◽  
Structural Studies ◽  
Solution Conformation ◽  
Phase Sensitive ◽  
Multiple Relay ◽  
C Nmr

The 1H and 13C NMR spectra of the cardenolides digitoxigenin, digoxigenin, digitoxin, and mono- and bis-digitoxigenin digitoxosides have been completely assigned by two-dimensional NMR spectroscopy. The techniques used include phase-sensitive COSY, multiple relay COSY, and carbon–proton correlation (HETCOR and HMQC) spectra. Various aspects of the solution conformation of the steroid moiety of digitoxin and digoxigenin could be determined from coupling constants and NOE difference experiments and they are indicative of an all-chair conformation. The carbohydrate rings in digitoxin and the mono- and bis-digitoxigenin digitoxosides are also in the chair conformation. Keywords: cardenolides, digitoxigenin, digitoxin, 2-dimensional NMR, conformational analysis.

Polymerization of n-butyl methylacrylate using bis(β- ketoamino)nickel(II)/MAO catalytic systems

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiaohui He ◽  
Yiwang Chen ◽  
Yongming Liu ◽  
Muqing Chen ◽  
Shuxian Yu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Monomer Concentration ◽  
Polymerization Temperature ◽  
Moderate Activity ◽  
Polymerization Time ◽  
Catalytic Systems ◽  
Molecular Weights ◽  
Molar Ratios ◽  
Broad Molecular Weight Distribution ◽  
C Nmr

AbstractThe polymerizations of n-butyl methylacrylate (nBMA) were carried out using bis(β-ketoamino)nickel(II) complexes (Ni[CH3C(O)CHC(NR)CH3]2: R = phenyl, 1; R = naphthyl, 2) in combination with methylaluminoxane (MAO) in toluene. The effect of parameters such as polymerization temperature, Al/Ni molar ratios, polymerization time, and monomer concentration, on catalytic polymerization activity and polymer molecular weights, were examined in detail. Both of the nickel(II) catalytic systems exhibited moderate activity, and produced P(nBMA) with high molecular weight and relatively broad molecular weight distribution (Mw/Mn=2.0~3.0. The obtained polymer has been characterized by means of FTIR, 1H NMR, 13C NMR, DSC, and WAXD technique and was confirmed to be syndio-rich stereospecific P(nBMA).

scholarly journals Two-stage alkaline and acid pretreatment applied to sugarcane bagasse to enrich the cellulosic fraction and improve enzymatic digestibility

Detritus ◽  
2020 ◽  
pp. 106-113
Author(s):  
Longinus Ifeanyi Igbojionu ◽  
Cecilia Laluce ◽  
Edison Pecoraro
Keyword(s):  
Sugarcane Bagasse ◽  
Maleic Acid ◽  
Ethanol Yield ◽  
High Yield ◽  
Enzymatic Digestibility ◽  
Acid Pretreatment ◽  
Two Stage ◽  
Second Stage ◽  
One Stage ◽  
Naoh Pretreatment

Sugarcane bagasse (SB) is made up of cellulose (32-43%), hemicellulose (19-34%) and lignin (14-30%). Due to high recalcitrant nature of SB, pretreatment is required to deconstruct its structure and enrich the cellulosic fraction. A two-stage NaOH and maleic acid pretreatment was applied to SB to enrich its cellulosic fraction. SB used in the present study is composed of cellulose (40.4 wt%), hemicellulose (20.9 wt%), lignin (22.5 wt%) and ash (4.0 wt%). After one-stage NaOH pretreatment, its cellulosic fraction increased to 61.8 wt% and later increased to 80.1 wt% after the second-stage acid pretreatment. Lignin fraction decreased to 3.0 wt% after one-stage NaOH pretreatment and remained unaffected after the acid pretreatment step. Hemicellulose fraction decreased substantially after the second-stage pretreatment with maleic acid. Pretreated SB displayed high crystallinity index and improved enzymatic digestibility. Hydrolysates of pretreated SB contained very low amount of xylose and subsequent fermentation by Saccharomyces cerevisiae -IQAr/45-1 resulted to ethanol level of 8.94 g/L. Maximal ethanol yield of 0.49 g/g (95.8% of theoretical yield) and productivity of 0.28 g/L/h was attained. At the same time, biomass yield and productivity of 0.47 g/g and 0.27 g/L/h respectively were obtained. Two-stage NaOH and maleic acid pretreatment led to ~ two-fold increase in cellulosic fraction and enhanced the enzymatic digestibility of SB up to 70.4%. The resulted enzymatic hydrolysate was efficiently utilized by S. cerevisiae -IQAr/45-1 to produce high yield of ethanol. Thus, optimization of enzymatic hydrolysis at low enzyme loading is expected to further improve the process and reduce cost.

Idification and structural characterisation of a catecholate-type siderophore produced by Stenotrophomonas maltophilia K279a

Microbiology ◽  
2021 ◽  
Vol 167 (7) ◽  
Author(s):  
Atsushi Hisatomi ◽  
Yuh Shiwa ◽  
Nobuyuki Fujita ◽  
Hiroyuki Koshino ◽  
Naoto Tanaka
Keyword(s):  
Stenotrophomonas Maltophilia ◽  
Type Species ◽  
Monomer Unit ◽  
Reversed Phase ◽  
Negative Bacterium ◽  
Content Type ◽  
Structural Characterisation ◽  
Link Type ◽  
Wide Range ◽  
C Nmr

Siderophores are produced by several bacteria that utilise iron in various environments. Elucidating the structure of a specific siderophore may have valuable applications in drug development. Stenotrophomonas maltophilia , a Gram-negative bacterium that inhabits a wide range of environments and can cause pneumonia, produces siderophores. However, the structure was unknown, and therefore, in this study, we aimed to elucidate it. We purified siderophores from cultures of S. maltophilia K279a using preparative reversed-phase HPLC. The structure was analysed through LC-MS and 1H and 13C NMR. The results demonstrated that S. maltophilia K279a produces 2,3-dihydroxybenzoylserine (DHBS), a monomer unit of enterobactin. We suggested the uptake of Iron(III) by the DHBS complex. DHBS production by S. maltophilia K279a could be attributed to an incomplete enterobactin pathway. Drugs targeting DHBS synthesis could prevent S. maltophilia infection.

Polysaccharides from the roots ofAlthaea officinalis L.: Structural features of D-glucans

1984 ◽  
Vol 49 (11) ◽  
pp. 2674-2679 ◽  
Author(s):  
Peter Capek ◽  
Rudolf Toman ◽  
Jozef Rosík ◽  
Alžbeta Kardošová ◽  
František Janeček
Keyword(s):  
Medicinal Plant ◽  
Structural Features ◽  
Gel Chromatography ◽  
Linear Character ◽  
Molecular Weights ◽  
Glycosidic Bonds ◽  
Althaea Officinalis ◽  
C Nmr

From the roots of the medicinal plant Althaea officinalis L., three D-glucans were isolated by gel chromatography which differed in molecular weights. The results of methylation analyses and 13C NMR measurements indicated predominantly linear character of the polysaccharide chains composed of α-D-glucopyranose units linked by 1 → 6 glycosidic bonds almost exclusively. The polymers had essentially the same structural features as D-glucan isolated from the leaves of this plant.

Structural studies of oligosilanes produced by catalytic dehydrogenative coupling of primary organosilanes

1987 ◽  
Vol 65 (8) ◽  
pp. 1804-1809 ◽  
Author(s):  
C. Aitken ◽  
J. F. Harrod ◽  
U. S. Gill
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Gel Permeation Chromatography ◽  
Structural Studies ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Dehydrogenative Coupling ◽  
Weight Distributions ◽  
Gel Permeation ◽  
End Groups

The structures of some poly(organosilylenes), [Formula: see text] (R = Ph, p-tolyl, n-hexyl, and benzyl), produced by catalytic dehydrogenative coupling of primary silanes have been studied by infrared, nuclear magnetic resonance, and mass spectroscopies. These results, combined with data on molecular weights and molecular weight distributions from vapour pressure osmometry and gel permeation chromatography, lead to the conclusion that the polymers are linear and have SiH2R end groups. The polymers all have degrees of polymerization of ca. 10 and very narrow molecular weight dipersions. Some possible features of the mechanism that gives rise to this behaviour are discussed.

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