Characterization of dissolved material during the initial phase of softwood kraft pulping

TAPPI Journal ◽  
2013 ◽  
Vol 12 (1) ◽  
pp. 37-43 ◽  
Author(s):  
HANNU PAKKANEN ◽  
TEEMU PALOHEIMO ◽  
RAIMO ALÉN
Keyword(s):  
Mass Transfer ◽  
Molecular Mass ◽  
Initial Phase ◽  
Degradation Products ◽  
Kraft Pulping ◽  
Reaction Products ◽  
Cooking Temperature ◽  
Molecular Masses ◽  
Aliphatic Carboxylic Acids

The influence of various cooking parameters, such as effective alkali, cooking temperature, and cooking time on the formation of high molecular mass lignin-derived and low molecular mass carbohydrates-derived (aliphatic carboxylic acids) degradation products, mainly during the initial phase of softwood kraft pulping was studied. In addition, the mass transfer of all of these degradation products was clarified based on their concentrations in the cooking liquor inside and outside of the chips. The results indicated that the degradation of the major hemicellulose component, galactoglucomannan, typically was dependent on temperature, and the maximum degradation amount was about 60%. In addition, about 60 min at 284°F (140°C) was needed for leveling off the concentrations of the characteristic reaction products (3,4-dideoxy-pentonic and glucoisosaccharinic acids) between these cooking liquors. Compared with low molecular mass aliphatic acids, the mass transfer of soluble lignin fragments with much higher molecular masses was clearly slower.

scholarly journals Alkali consumption of aliphatic carboxylic acids during alkaline pulping of wood and nonwood feedstocks

Holzforschung ◽  
2013 ◽  
Vol 67 (6) ◽  
pp. 643-650 ◽  
Author(s):  
Hannu Pakkanen ◽  
Raimo Alén
Keyword(s):  
Wheat Straw ◽  
Degradation Products ◽  
Dicarboxylic Acids ◽  
Kraft Pulping ◽  
Alkaline Pulping ◽  
Carbohydrate Degradation ◽  
Cooking Temperature ◽  
Alkali Consumption ◽  
Aliphatic Carboxylic Acids ◽  
Acetic Acids

Abstract The carbohydrate degradation products have been examined, which are formed during the conventional kraft pulping of a softwood, hardwoods, bamboo, and wheat straw as well as soda and soda-anthraquinone pulping of wheat straw. The focus was on “volatile” acids such as formic and acetic acids and “nonvolatile” hydroxy monocarboxylic and dicarboxylic acids. The different consumption profiles were obtained for the charged alkali required for the neutralization of these aliphatic acids depending on the feedstock and the cooking method. The relative composition of the acid fraction in the black liquors of softwood and hardwood and nonwood feedstocks showed characteristic variations. However, in the case of wood kraft pulping, the variations in cooking conditions (effective alkali 19–21% and cooking temperature 155–170°C) had no significant effect on the acid composition. The total amount of volatile and hydroxy acids formed during pulping at a typical target κ number level for each feedstock ranged from 78 to 174 kg ton-1 based on o.d. feedstock. It was highest in birch kraft pulping and lowest in wheat soda-anthraquinone pulping.

Purification and characterization of a lectin from Xanthomonas campestris NCIM 5028

1996 ◽  
Vol 42 (6) ◽  
pp. 609-612 ◽  
Author(s):  
Bhagyashree Joshi ◽  
Jayant M. Khire ◽  
Hephzibah SivaRaman ◽  
M. Islam Khan
Keyword(s):  
Molecular Mass ◽  
Host Plant ◽  
Xanthomonas Campestris ◽  
Simple Procedure ◽  
Gel Filtration ◽  
Purification And Characterization ◽  
Ammonium Sulphate Precipitation ◽  
Molecular Masses ◽  
Lectin Purification

A lectin was isolated from culture filtrates of Xanthomonas campestris NCIM 5028, by a simple procedure of hydrophobic chromatography on phenyl-Sepharose after ammonium sulphate precipitation. The lectin was a heterodimer, with subunit molecular masses of 30 000 and 28 000. Gel filtration on S-300 column, calibrated with markers, showed its molecular mass to be approximately 70 000. Its isoelectric point was 7.2. The agglutination of the rabbit erythrocytes by the lectin was inhibited by fetuin glycopeptides and host plant (Brassica oleracea) extracts.Key words: Xanthomonas campestris, lectin, purification.

scholarly journals Localization and characterization of two structurally different forms of acetyl-CoA carboxylase in young pea leaves, of which one is sensitive to aryloxyphenoxypropionate herbicides

1994 ◽  
Vol 300 (2) ◽  
pp. 557-565 ◽  
Author(s):  
C Alban ◽  
P Baldet ◽  
R Douce
Keyword(s):  
Molecular Mass ◽  
Subunit Structure ◽  
Acetyl Coa Carboxylase ◽  
Leaf Extracts ◽  
Acetyl Coa ◽  
Native Molecular Mass ◽  
Molecular Masses ◽  
Minor Form ◽  
A Minor

Young pea leaves contain two structurally different forms of acetyl-CoA carboxylase (EC 6.4.1.2; ACCase). A minor form, which accounted for about 20% of the total ACCase activity in the whole leaf, was detected in the epidermal tissue. This enzyme was soluble and was purified to homogeneity from young pea leaf extracts. It consisted of a dimer of two identical biotinyl subunits of molecular mass 220 kDa. In this respect, this multifunctional enzyme was comparable with that described in other plants and in other eukaryotes. A predominant form was present in both the epidermal and mesophyll tissues. In mesophyll protoplasts, ACCase was detected exclusively in the soluble phase of chloroplasts. This enzyme was partially purified from pea chloroplasts and consisted of a freely dissociating complex, the activity of which may be restored by combination of its separated constituents. The partially purified enzyme was composed of several subunits of molecular masses ranging from 32 to 79 kDa, for a native molecular mass > 600 kDa. One of these subunits, of molecular mass 38 kDa, was biotinylated. This complex subunit structure was comparable with that of microorganisms and was referred to as a ‘prokaryotic’ form of ACCase. Biochemical parameters were determined for both ACCase forms. Finally, both pea leaf ACCases exhibited different sensitivities towards the grass ACCase herbicide, diclofop. This compound had no effect on the ‘prokaryotic’ form of ACCase, while the ‘eukaryotic’ form was strongly inhibited.

scholarly journals Purification and Partial Characterization of Melanoidins Fractions from Toasted Oak Heartwood, Comparison with Melanoidins from Roasted Coffee

2018 ◽  
Vol 7 (6) ◽  
pp. 37 ◽  
Author(s):  
M. F. Nonier ◽  
N. Vivas ◽  
N. Vivas de Gaulejac ◽  
C. Mouche ◽  
C. Rossy Huguet ◽  
...  
Keyword(s):  
Antioxidant Activities ◽  
Degradation Products ◽  
Partial Characterization ◽  
Maillard Reaction Products ◽  
Reaction Products ◽  
Roasted Coffee ◽  
Oak Wood ◽  
Processing And Storage ◽  
And Storage

During the cooking, processing, and storage of food products, a whole range of browning reactions occurs, initiated by the reaction of a carbohydrate with a compound possessing a free amino group. Melanoidins formed, influence food quality, mainly their colour, their flavour, and their antioxidant activities. Melanoidins are complex Maillard reaction products. We developed a method to isolate coffee melanoidins and melanoidins from toasted oak wood. We noted that coffee is richer in melanoidin compounds than oak wood. We presented a partial characterization of melanoidins fractions from toasted oak heartwood, and a comparison with melanoidins from roasted coffee. Mass spectra of the fractions isolated from toasted oak wood indicate the presence of pentose and hexose-based oligosaccharides with different degrees of polymerisation. The presence of the oligosaccharide moieties, as well as their degradation products found in the oak wood melanoidins, supports the postulated carbohydrate-based origin of melanoidins.

Effect of dextran and enzymatically decomposed dextran on the sucrose crystal shape

2019 ◽  
pp. 588-596
Author(s):  
Karin Abraham ◽  
Henriette Brykczynski ◽  
E.S.J. Rudolph-Flöter ◽  
Karl Schlumbach ◽  
A. Schäfer ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Molecular Mass Distribution ◽  
Size Exclusion ◽  
Crystal Shape ◽  
Reaction Products ◽  
Mass Distributions ◽  
Crystallization Experiments ◽  
Exclusion Chromatography ◽  
Molecular Masses ◽  
Sucrose Crystals

The effect of dextran’s molecular mass distribution on the sucrose crystal shape was key to this study. Therefore, sucrose crystals were produced by evaporating crystallization experiments using synthetic thick juices in the form of pure sugar syrups containing high (T2000) and low (T40) molecular mass dextran fractions as well as enzymatically decomposed dextran. The combined analysis of molecular mass distributions by size exclusion chromatography and sucrose crystal shapes by static image analysis were used to identify the least harmful reaction products resulting from the enzymatic decomposition of dextran. The combined evaluation of two shape parameters, circularity and width-to-length ratio, has shown that three different shape modifications can be related to the presence of dextran, namely cube-shaped crystals, elongated needle-shaped crystals and agglomerates. In the main, the data indicated that high T2000 contents and generally all T40 dextran contents led to an increased occurrence of agglomerated and occasionally elongated crystals. The latter was especially found for high T2000 dextran contents. In contrast, low T2000 dextran contents predominantly increased the amount of cube-like crystals. The enzymatic decomposition of dextran resulted in a gradual reduction of the molecular mass. It was shown that an insufficient decomposition to broadly distributed low molecular mass dextran fragments, which are realistic to assume for technical cane and beet juices, still dramatically affected the sucrose crystal shape. Once dextran was decomposed to molecules with molecular masses of less than 5 kDa, no dextran-related effects on the sucrose crystal shape were found.

scholarly journals Bovine cartilage types VI and IX collagens. Characterization of their forms in vivo

1989 ◽  
Vol 262 (3) ◽  
pp. 753-761 ◽  
Author(s):  
S Ayad ◽  
A Marriott ◽  
K Morgan ◽  
M E Grant
Keyword(s):  
Molecular Mass ◽  
Proteinase Inhibitors ◽  
Guanidinium Chloride ◽  
Type Vi Collagen ◽  
Pepsin Digestion ◽  
Molecular Masses ◽  
Biosynthetic Studies ◽  
Bovine Cartilage

1. Collagens were extracted from bovine cartilage by 4 M-guanidinium chloride in the presence of proteinase inhibitors and identified by immunoblotting with specific anti-collagen sera. 2. The collagens retained their native conformations (shown by the resistance of their triple-helical domains to pepsin digestion), and the molecular masses of their component alpha-chains indicated that the chains were intact. 3. Type VI collagen was extracted as a large-molecular-mass disulphide-bonded aggregate composed of components of molecular mass 140 kDa and 200-240 kDa, and was therefore similar to type VI collagen identified in noncartilaginous tissues. Immunoblotting established the 200-240 kDa components as intact forms of the alpha 3(VI) chain. 4. Type IX collagen consisted of three clearly separable components of molecular mass 84 kDa, 72 kDa and 66 kDa, which were assigned to the alpha 1(IX)-, alpha 3(IX)- and alpha 2(IX)-chains respectively, and a large proportion of this collagen had no covalently bound glycosaminoglycan attached to the alpha 2(IX)-chain. 5. Differences between the type IX collagen extracted from bovine cartilage and that identified in biosynthetic studies on chick cartilage are discussed.

Characterization of Black Liquors from Soda-AQ Pulping of Reed Canary Grass (Phalaris arundinacea L.)

Holzforschung ◽  
2002 ◽  
Vol 56 (3) ◽  
pp. 298-303 ◽  
Author(s):  
Z. Feng ◽  
R. Alén ◽  
H. Pakkanen
Keyword(s):  
Chemical Composition ◽  
Wide Distribution ◽  
Phalaris Arundinacea ◽  
Reed Canary Grass ◽  
Molecular Masses ◽  
Canary Grass ◽  
Black Liquors ◽  
Average Molecular Masses ◽  
Aliphatic Carboxylic Acids

Summary Reed canary grass (Phalaris arundinacea L.) was delignified in a laboratory-scale digester by conventional soda-AQ pulping under varying conditions. The chemical composition of the corresponding black liquors was analyzed with respect to their main organic constituents. The results showed that the dry solids of the black liquors contained 33–34% lignin, 14–19% aliphatic carboxylic acids and 12–16% polysaccharides. No significant differences were found in the average molecular masses (M̄w 4700–5600 Da and M̄n 650–750 Da) of the dissolved lignins in these black liquors, although the polydispersity (M̄w /M̄n ) values (6.6–7.9) indicated that the molecular masses had a wide distribution. Lignin clearly degraded in the black liquors as delignification proceeded. Of the monosaccharide moieties detected in the polysaccharides, xylose was predominant, suggesting that xylan was a major hemicellulose constituent in the black liquors.

Purification and partial characterization of peptidase-1, a sex-linked enzyme inPleurodeles waltl(urodele amphibian)

1997 ◽  
Vol 75 (6) ◽  
pp. 803-806 ◽  
Author(s):  
Etienne Rudolf ◽  
Jean-Michel Girardet ◽  
Anne-Marie Bautz ◽  
Christian Dournon
Keyword(s):  
Ethylene Glycol ◽  
Molecular Mass ◽  
Subcellular Fraction ◽  
Gel Filtration ◽  
Tetraacetic Acid ◽  
Optimal Activity ◽  
Isoelectric Points ◽  
Molecular Masses ◽  
Pleurodeles Waltl

Peptidase-1 is a sex-linked enzyme, which can be purified from the liver of the amphibian urodele Pleurodeles waltl. We estimated its apparent molecular mass as 170 kDa by gel filtration chromatography. The enzyme is composed of two subunits with apparent molecular masses of 90 and 99 kDa. It is strongly inhibited by ethylenediaminotetraacetic acid, ethylene glycol bis( beta -aminoethyl ether)-N,N-tetraacetic acid, and 1,10-phenanthroline, indicating that peptidase-1 is a metallopeptidase. Peptidase-1 has optimal activity at 55°C and pH 8.5. This acidic enzyme displays two apparent isoelectric points, at 4.9 and 5.2, and is essentially located in the cytosolic subcellular fraction.Key words: peptidase-1, amphibian, purification, characterization, sex-linked enzyme.

scholarly journals Purification and characterization of a connective-tissue-degrading metalloproteinase from the cytosol of metastatic melanoma cells

1987 ◽  
Vol 245 (2) ◽  
pp. 429-437 ◽  
Author(s):  
S Zucker ◽  
T Turpeenniemi-Hujanen ◽  
N Ramamurthy ◽  
J Wieman ◽  
R Lysik ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Type I Collagen ◽  
Collagen Type I ◽  
Enzymic Activity ◽  
Affinity Column ◽  
Type I ◽  
Type Iv ◽  
Affinity Column Chromatography ◽  
Molecular Masses

A metalloproteinase with activity against type IV collagen, type I collagen and gelatin has been purified from the cytosol of a highly metastatic mouse melanoma by anion-exchange, zinc-chelated and lectin-affinity column chromatography. The purified enzyme has a molecular mass of approx. 59 kDa and on isoelectric focusing in two-dimensional gels produced three spots with apparent isoelectric points (pI) between 5.7 and 6.1. Enzymic activity with collagen, but not gelatin, substrates was latent, requiring activation by trypsin or organomercurials. Trypsin activation of this metalloproteinase was accompanied by a change in molecular mass, whereas autoactivation after 1 month's storage, was not. The degradation of types I and IV collagen by the melanoma enzyme yielded products of lower molecular masses than those yielded by mammalian collagenases, this characteristic thus differentiating this metalloproteinase from classical collagenases.

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