The color characteristics of the pigment coated leather and checkered card were analyzed by using CIELAB color measurement. These treatments allow a broad modification of the surface
In this particular case of what sounds like a photochemical reaction of lignin with oxygen, how is a chromophore produced? Or, is it really even true that a chromophore is responsible for the yellow color of yellowed paper? Or is it the oxidation and loss of a fluorophore that was originally making the paper look white?
Laccase is a key enzyme in plant lignin biosynthesis as it catalyzes the final step of monolignols polymerization. Sweet sorghum Sorghum bicolor L. Moench is considered as an ideal feedstock for ethanol production, but lignin greatly limits the production efficiency. No comprehensive analysis on laccase has ever been conducted in S. bicolor, although it appears as the most promising target
Lignin dispersant prepared from soda lignin or kraft lignin is usually obtained by the sulfonation of lignin. In some cases modifications are conducted after sulfonation to reduce the color 18 , 19 .
Lignin modification could bypass the need for acid pretreatment and thereby facilitate bioprocess consolidation. Main. Accessibility of plant cell wall polysaccharides to chemical,
Reduction of lignin levels in the forage legume alfalfa Medicago sativa by down-regulation of the monolignol biosynthetic enzyme hydroxycinnamoyl coenzyme A:shikimate hydroxycinnamoyl transferase HCT results in strongly increased digestibility and processing ability of lignocellulose. However, these modifications are often also associated with dwarfing and other changes in plant growth.
New Insights into Lignin Modification during Chlorine Dioxide Bleaching Sequences IV : The Impact of Modifications in the EP and EOP Stages on the D 1 Stage Brian N. Brogdon et al. Journal of Wood Chemistry and Technology
Lignin modification through acetylation reduced the lignin color and improved visible light transmission of films without significantly affecting the UV-absorption properties. Presence of lignin also enhanced the thermal and contact angle stability of the films.
Lignin engineering through laccase modification: a promising field for energy plant improvement Jinhui Wang 1, Juanjuan Feng1, Weitao Jia1, Sandra Chang2,3, Shizhong Li2,3 and Yinxin Li1* Abstract Laccase p-diphenol:dioxygen oxidoreductase, EC is a member of the multicopper oxidases and catalyzes
The application and modification of natural lignin in water treatment have attracted significant attention recently. An environmental friendly lignin-based flocculant LBF with enhanced flocculation effect was prepared from paper mill sludge in this work.
Sulfonated lignin and lignosulfonate color reductions of over 90 percent, and in some cases as high as 95 percent, are achieved by a two-step process involving the blocking of phenolic groups on the lignin molecule with known blocking agents followed by oxidation with chlorine dioxide. The light colored lignin dispersants produced by the invention process exhibit very low staining and low azo
Color and Property Evaluation of Blocked and Oxidized Sulfonated Lignin and Lignosulfonates Fiber Staining Azo Dye Heat Light Color Color Stability Reflec- Reduction Retention Viscosity Modification Filter tance Over Over at 50% Starting moles/1000 grams Residue in % * Control Control Solids Material Sulfonated Lignin in mg pH 4 pH 7 in
Improvement of biomass through lignin modification. The knowledge gained from these bioengineering efforts has greatly improved our understanding of the optimal lignin characteristics required for various applications of lignocellulosic materials while also contributing to our understanding of the lignin biosynthetic pathway. The recent
Some of the residual lignin that used to be removed by bleaching is now being removed in some pulp mills by extended delignification, which Smook defines as "Kraft pulping modification within a continuous digester which utilizes a two-stage, partially counter-current cooking sequence to achieve lower kappa number and improved overall washing
20 mmV20 mmV1.5 mm obtained throughdelignification top and lignin modification bottom . Scheme2.Representative lignin reactionsand structurescontributing to wood color,aswell as the main
Lignin is a class of complex organic polymers that form key structural materials in the support tissues of vascular plants and some algae. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity and do not rot easily.Chemically, lignins are cross-linked phenolic polymers.
As lignin directly limits the fermentation yield, its removal by pretreatment or modification prior to enzymatic hydrolysis and fermentation would be advantageous. Genetic engineering of plant cell wall has been considered as a promising strategy for desirable lignin content and/or composition towards higher biofuel production 5 .
It is commonly known that lignin is the main cause of color change. Due to its optical characteristics lignin is a good absorber of light of various wavelengths compared to other wood compounds
The dark color of industrial lignin is the main obstacle for their high value-added use in areas such as sunscreen or dyestuff dispersants. Here, a one-step method for reducing the color of lignin is presented and the structural changes of the whitened lignin are characterized by UV, FTIR, NMR, GPC, DLS, AFM, HS-GC and potentiometric titration.
Lignin modification could bypass the need for acid pretreatment and thereby facilitate bioprocess consolidation. Access options Access options. Subscribe to Journal. Get full journal access for 1
lignin color modification 1 Field of the InventionThis invention relates to reducing the color of lignin. More particularly, this invention relates to a two-step process for reducing the The section entitled "Mechanical Pulps, Lignin and Color Change" contains new information. Other sections are identical to those circulated with the
Different pulping processes and lignin extraction method to obtain the main physical and chemical properties include the following: 1, the color of lignin Original lignin is a white or nearly colorless material. We see the color of lignin, in isolation, caused by the preparation process.
Influence of Lignin modification on PAN-Lignin copolymers as potential carbon fiber precursors by Gauri Ramasubramanian A thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of Master of Science Major: Materials Science and Engineering Program of Study Committee Michael R. Kessler, Major Professor
Modification of Lignin and Lignin Rich Fibers via Oxoreductase Enzymes The rapid color formation upon laccase treatment should indicate the formation of quinone structures from phenolic hydroxyl groups. The observed increases in molecular weight were from an average of 3,200 to 20,000 g/mol.10
hemicellulose and lignin into platform molecules: biotechnological approach Anders Frölander Gudbrand Rødsrud Borregaard Industries Ltd, Norway EuroBioRef Summer school Lecce, Italy 18-24 September 2011 . Outline 1. Introduction 2. History of second generation bioethanol production 3. Worlds most advanced biorefinery history and
Lignin is a heterogeneous, phenolic and polydisperse biopolymer which resists degradation due to its aromatic and highly branched structure. Lignin is the most abundant renewable source of aromatic molecules on earth. The valorization of lignin could therefore provide a sustainable alternative to petroleum refineries for the production of valuable aromatic compounds.
Lignin accounts for approximately 30% of the organic carbon in the biosphere, and it is the second most abundant biopolymer of lignocellulosic biomass, after cellulose .It is commonly distributed in combination with hemicellulose around the cellulose strands in primary and secondary cell walls, and it is covalently bonded to the carbohydrate/cellulose structure Fig. 1a , .
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