scholarly journals Radical Depolymerization of Alginate Extracted from Moroccan Brown Seaweed Bifurcaria bifurcata

2020 ◽  
Vol 10 (12) ◽  
pp. 4166 ◽  
Author(s):  
Bouissil Soukaina ◽  
EL Alaoui-Talibi Zainab ◽  
Pierre Guillaume ◽  
Rchid Halima ◽  
Michaud Philippe ◽  
...  
Keyword(s):  
Green Chemistry ◽  
High Performance ◽  
Atlantic Coast ◽  
Brown Seaweed ◽  
Amperometric Detection ◽  
Degree Of Polymerization ◽  
Exchange Chromatography ◽  
Size Exclusion ◽  
Bifurcaria Bifurcata

The degradation of alginate extracted from Moroccan Bifurcaria bifurcata has not been fully established to date. In this work, we report the extraction and the characterization of alginate (ASBB) from the brown algae B. bifurcata, as well as the production of oligo-alginates (OGABs) by using a green chemistry process. The depolymerization of ASBB was carried out by controlled radical hydrolysis through our green chemistry process using a hydrogen peroxide (H2O2) catalyst. The molecular weight (Mw) and degree of polymerization (DP) distribution of oligo-alginates (OGABs) obtained were then characterized by HPLC size exclusion chromatography (SEC) and high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Structural characterization revealed that after 6 h of depolymerization of ASBB, we obtained OGABs with Mw ≤ 5.5 kDa and 2 ≤ DP ≤ 24. These results highlight the effectiveness of the controlled radical hydrolysis of alginate to produce good yields of alginate fractions with controlled Mw with a known polymerization degree (DP) and without altering properties of oligo-alginates. Bifurcaria bifurcata can be a potential source of alginate and oligo-alginates given its abundance on the northwest Atlantic coast. The production and characterization of oligo-alginates promote their exploitation in the cosmetic, pharmaceutic, and agriculture fields.

scholarly journals Enzymatic Synthesis and Characterization of Different Families of Chitooligosaccharides and Their Bioactive Properties

2021 ◽  
Vol 11 (7) ◽  
pp. 3212
Author(s):  
Noa Miguez ◽  
Peter Kidibule ◽  
Paloma Santos-Moriano ◽  
Antonio O. Ballesteros ◽  
Maria Fernandez-Lobato ◽  
...  
Keyword(s):  
High Performance ◽  
Chemical Characterization ◽  
Amperometric Detection ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Enzymatic Production ◽  
Bioactive Properties ◽  
Substrate Properties ◽  
Chitin Hydrolysis

Chitooligosaccharides (COS) are homo- or hetero-oligomers of D-glucosamine (GlcN) and N-acetyl-D-glucosamine (GlcNAc) that can be obtained by chitosan or chitin hydrolysis. Their enzymatic production is preferred over other methodologies (physical, chemical, etc.) due to the mild conditions required, the fewer amounts of waste and its efficiency to control product composition. By properly selecting the enzyme (chitinase, chitosanase or nonspecific enzymes) and the substrate properties (degree of deacetylation, molecular weight, etc.), it is possible to direct the synthesis towards any of the three COS types: fully acetylated (faCOS), partially acetylated (paCOS) and fully deacetylated (fdCOS). In this article, we review the main strategies to steer the COS production towards a specific group. The chemical characterization of COS by advanced techniques, e.g., high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and MALDI-TOF mass spectrometry, is critical for structure–function studies. The scaling of processes to synthesize specific COS mixtures is difficult due to the low solubility of chitin/chitosan, the heterogeneity of the reaction mixtures, and high amounts of salts. Enzyme immobilization can help to minimize such hurdles. The main bioactive properties of COS are herein reviewed. Finally, the anti-inflammatory activity of three COS mixtures was assayed in murine macrophages after stimulation with lipopolysaccharides.

Saccharide and fructooligosaccharide accumulation across leaf-bases during growth and bulb development of onion ( Allium cepa L.)

2008 ◽  
Vol 56 (1) ◽  
pp. 21-31 ◽  
Author(s):  
N. Shiomi ◽  
N. Benkeblia ◽  
S. Onodera ◽  
N. Takahashi ◽  
M. Fujishima ◽  
...  
Keyword(s):  
Allium Cepa ◽  
High Performance ◽  
Amperometric Detection ◽  
Anion Exchange Chromatography ◽  
Degree Of Polymerization ◽  
Exchange Chromatography ◽  
Glucose Content ◽  
Bulb Formation ◽  
Total Carbohydrates ◽  
June July

The accumulation of saccharides and fructooligosaccharides (FOS) in the individual leaf-bases of onion ( Allium cepa L.) was investigated during growth and bulb development. Saccharides and FOS were analysed by means of high performance anion exchange chromatography-pulsed amperometric detection (HPAEC-PAD). The glucose content was the highest, while the content of saccharides (glucose, fructose and sucrose) increased during June, July and August and decreased slightly during September. The trisaccharides all accumulated to a similar extent, although the neokestose [ 3b , 6 G - β -D fructofuranosylsucrose] content was higher than that of 1-kestose [ 3a , 1 F - β -D-fructofuranosylsucrose]. Tetra-, penta- and high-DP (degree of polymerization) FOS also showed a similar pattern, though the contents of 4b [6 G (1- β -D-fructofuranosyl) 2 sucrose] and 5b [6 G (1- β -D-fructofuranosyl) 3 sucrose] were higher compared with that of other tetra-[ 4a , 1 F (1- β -D-fructofuranosyl) 2 sucrose and 4c , 1 F , 6 G -di- β -D-fructofuranosyl sucrose] and penta-saccharides [ 5a , 1 F (1- β -D-fructofuranosyl) 3 sucrose]. Total FOS accumulated to a greater extent in the inner (youngest) leaf-bases than in the outer (oldest) leaf-bases, and their content was high during August. The total carbohydrates content was 6.71, 7.25, 8.10 and 6.30 g 100 g −1 FW during June, July, August and September, respectively. During bulb formation, a balance was observed between the glucose, fructose, sucrose and FOS contents, with an average ratio of 20:10:10:60 of total carbohydrates, respectively.

scholarly journals CHARACTERIZATION OF INULIN FROM BLACK SALSIFY (SCORZONERA HISPANICA L.) FOR FOOD AND PHARMACEUTICAL PURPOSES

2018 ◽  
Vol 11 (12) ◽  
pp. 221 ◽  
Author(s):  
Nadezhda Petkova
Keyword(s):  
High Performance ◽  
Chemical Characterization ◽  
Degree Of Polymerization ◽  
Size Exclusion ◽  
Future Application ◽  
Coating Agent ◽  
Swelling Capacity ◽  
Exclusion Chromatography ◽  
Water Holding

Objective: The aim of the current study was to evaluate the black salsify (Scorzonera hispanica L.) as a potential source of inulin and to characterize the physicochemical properties of isolated polysaccharide.Methods: The carbohydrate content in its roots and leaves was analyzed by high-performance liquid chromatography with refractive index detection (HPLC-RID) method. Microwave-assisted extraction was performed for isolation of inulin from black salsify roots. The obtained polysaccharide was characterized by HPLC-RID method, HPLC size-exclusion chromatography, and Fourier transformed-infrared spectroscopy. Functional properties as swelling capacity, solubility, and water-holding and oil-holding capacities (OHCs) were also evaluated.Results: Black salsify (S. hispanica L.) roots were evaluated as a rich source of inulin (22% dw) and 1-kestose (6.25 g/100 g dw). The isolated inulin (yield 20%) was characterized with average degree of polymerization 17, with polydispersity index (1.04) that was near to medium-chained inulin. This polysaccharide showed better OHC than water-holding capacity, and it was characterized with swelling capacity 0.5 ml/g sample.Conclusion: For the first time, inulin was isolated from black salsify roots. The chemical characterization of inulin reveals the potential of this plant to be used as a valuable source of this polysaccharide for future application in food technology and pharmaceutical industry for dietary fibers, stabilizer, and coating agent.

scholarly journals Mode of action and subsite studies of the guluronan block-forming mannuronan C-5 epimerases AlgE1 and AlgE6

2006 ◽  
Vol 395 (2) ◽  
pp. 319-329 ◽  
Author(s):  
Synnøve Holtan ◽  
Per Bruheim ◽  
Gudmund Skjåk-Bræk
Keyword(s):  
High Performance ◽  
Azotobacter Vinelandii ◽  
Block Size ◽  
Amperometric Detection ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Size Exclusion ◽  
Mannuronic Acid ◽  
Enzyme Degradation ◽  
Exclusion Chromatography

AlgE1, AlgE5 and AlgE6 are members of a family of mannuronan C-5 epimerases encoded by the bacterium Azotobacter vinelandii, and are active in the biosynthesis of alginate, where they catalyse the post-polymerization conversion of β-D-mannuronic acid (M) residues into α-L-guluronic acid residues (G). All enzymes show preference for introducing G-residues neighbouring a pre-existing G. They also have the capacity to convert single M residues flanked by G, thus ‘condensing’ G-blocks to form almost homopolymeric guluronan. Analysis of the length and distribution of G-blocks based on specific enzyme degradation combined with size-exclusion chromatography, electrospray ionization MS, HPAEC–PAD (high-performance anion-exchange chromatography and pulsed amperometric detection), MALDI (matrix-assisted laser-desorption ionization)-MS and NMR revealed large differences in block length and distribution generated by AlgE1 and AlgE6, probably reflecting their different degree of processivity. When acting on polyMG as substrates, AlgE1 initially forms only long homopolymeric G-blocks >50, while AlgE6 gives shorter blocks with a broader block size distribution. Analyses of the AlgE1 and AlgE6 subsite specificities by the same methodology showed that a mannuronan octamer and heptamer respectively were the minimum substrate chain lengths needed to accommodate enzyme activities. The fourth M residue from the non-reducing end is epimerized first by both enzymes. When acting on MG-oligomers, AlgE1 needed a decamer while AlgE6 an octamer to accommodate activity. By performing FIA (flow injection analysis)-MS on the lyase digests of epimerized and standard MG-oligomers, the M residue in position 5 from the non-reducing end was preferentially attacked by both enzymes, creating an MGMGGG-sequence (underlined and boldface indicate the epimerized residue).

scholarly journals Autocatalytic Fractionation of Wood Hemicelluloses: Modeling of Multistage Operation

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 337
Author(s):  
Mar López ◽  
Valentín Santos ◽  
Juan Carlos Parajó
Keyword(s):  
Liquid Phase ◽  
High Performance ◽  
Amperometric Detection ◽  
Anion Exchange Chromatography ◽  
Optimal Recovery ◽  
Exchange Chromatography ◽  
Size Exclusion ◽  
Reaction Products ◽  
Flight Mass Spectrometry ◽  
Kinetic Coefficients

Eucalyptus globulus wood samples were treated with hot, compressed water (autohydrolysis) in consecutive stages under non-isothermal conditions in order to convert the hemicellulose fraction into soluble compounds through reactions catalyzed by in situ generated acids. The first stage was a conventional autohydrolysis, and liquid phase obtained under conditions leading to an optimal recovery of soluble saccharides was employed in a new reaction (second crossflow stage) using a fresh wood lot, in order to increase the concentrations of soluble saccharides. In the third crossflow stage, the best liquid phase from the second stage was employed to solubilize the hemicelluloses from a fresh wood lot. The concentration profiles determined for the soluble saccharides, acids, and furans present in the liquid phases from the diverse crossflow stages were employed for kinetic modeling, based on pseudohomogeneous reactions and Arrhenius-type dependence of the kinetic coefficients on temperature. Additional characterization of the reaction products by High Pressure Size Exclusion Chromatography, High Performance Anion Exchange Chromatography with Pulsed Amperometric Detection, and Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry provided further insight on the properties of the soluble saccharides present in the various reaction media.

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