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Sample records for acid-precipitable polymeric lignin

  1. Biologically produced acid precipitable polymeric lignin

    DOEpatents

    Crawford, Don L.; Pometto, III, Anthony L.

    1984-01-01

    A water soluble, acid precipitable polymeric degraded lignin (APPL), having a molecular weight of at least 12,000 daltons, and comprising, by percentage of total weight, at least three times the number of phenolic hydroxyl groups and carboxylic acid groups present in native lignin. The APPL may be modified by chemical oxidation and reduction to increase its phenolic hydroxyl content and reduce the number of its antioxidant inhibitory side chains, thereby improving antioxidant properties.

  2. Chemical factors that control lignin polymerization.

    PubMed

    Sangha, Amandeep K; Davison, Brian H; Standaert, Robert F; Davis, Mark F; Smith, Jeremy C; Parks, Jerry M

    2014-01-01

    Lignin is a complex, branched polymer that reinforces plant tissue. Understanding the factors that govern lignin structure is of central importance to the development of technologies for converting lignocellulosic biomass into fuels because lignin imparts resistance to chemical, enzymatic, and mechanical deconstruction. Lignin is formed by enzymatic oxidation of phenolic monomers (monolignols) of three main types, guaiacyl (G), syringyl (S), and p-hydroxyphenyl (H) subunits. It is known that increasing the relative abundance of H subunits results in lower molecular weight lignin polymers and hence more easily deconstructed biomass, but it is not known why. Here, we report an analysis of frontier molecular orbitals in mono-, di-, and trilignols, calculated using density functional theory, which points to a requirement of strong p-electron density on the reacting phenolic oxygen atom of the neutral precursor for enzymatic oxidation to occur. This model is consistent with a proton-coupled electron transfer (PCET) mechanism and for the first time explains why H subunits in certain linkages (β-β or β-5) react poorly and tend to "cap" the polymer. In general, β-5 linkages with either a G or H terminus are predicted to inhibit elongation. More broadly, the model correctly accounts for the reactivity of the phenolic groups in a diverse set of dilignols comprising H and G subunits. Thus, we provide a coherent framework for understanding the propensity toward growth or termination of different terminal subunits in lignin. PMID:24341896

  3. Chemical factors that control lignin polymerization

    SciTech Connect

    Sangha, Amandeep K; Davison, Brian H; Standaert, Robert F; Davis, Dr. Mark F.; Smith, Jeremy C; Parks, Jerry M

    2014-01-01

    Lignin is a complex, branched polymer that reinforces plant tissue. Understanding the factors that govern lignin structure is of central importance to the development of technologies for converting lignocellulosic biomass into fuels because lignin imparts resistance to chemical, enzymatic and mechanical deconstruction. Lignin is formed by enzymatic oxidation of phenolic monomers (monolignols) of three main types, guaiacyl (G), syringyl (S) and p- hydroxyphenyl (H). It is known that increasing the relative abundance of H subunits results in lower molecular-weight lignin polymers, and hence more easily deconstructed biomass, but it is not known why. Here, we report an analysis of frontier molecular orbitals in mono-, di- and trilignols, calculated using density functional theory, which points to a requirement of strong p- electron density on the reacting phenolic oxygen atom of the neutral precursor for enzymatic oxidation to occur. This model is consistent with a proton-coupled electron transfer (PCET) mechanism and for the first time explains why H subunits in certain linkages ( - or -5) react poorly and tend to cap the polymer. In general, -5 linkages with either a G or H terminus are predicted to inhibit elongation. More broadly, the model correctly accounts for the reactivity of the phenolic groups in a diverse set of dilignols comprising H and G subunits. Thus, we provide a coherent framework for understanding the propensity toward growth or termination of different terminal subunits in lignin.

  4. Acidic precipitation

    SciTech Connect

    Martin, H.C.

    1987-01-01

    At the International Symposium on Acidic Precipitation, over 400 papers were presented, and nearly 200 of them are included here. They provide an overview of the present state of the art of acid rain research. The Conference focused on atmospheric science (monitoring, source-receptor relationships), aquatic effects (marine eutrophication, lake acidification, impacts on plant and fish populations), and terrestrial effects (forest decline, soil acidification, etc.).

  5. p-Hydroxyphenyl (H) Units Lower the Degree of Polymerization in Lignin: Chemical Control in Lignin Biosynthesis

    SciTech Connect

    Sangha, A. K.; Parks, J. M.; Davis, M. F.; Smith, J. C.

    2013-01-01

    Lignin, composed predominantly of p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) subunits, is a major component of plant cell walls that imparts resistance toward chemical and microbial deconstruction of plant biomass, rendering its conversion inefficient and costly. Previous studies have shown that alterating lignin composition, i.e., the relative abundance of H, G and S subunits, promises more efficient extraction of sugars from plant biomass. Smaller and less branched lignin chains are more easily extracted during pretreatment, making cellulose more readily degradable. Here, using density functional theory calculations, we show that the incorporation of H subunits into lignin via b-b and b-5 interunit linkages reduces the degree of polymerization in lignin. Frontier molecular orbital analyses of lignin dimers and trimers show that H as a terminal subunit on a growing lignin polymer linked via b-b and b-5 linkage cannot undergo radical formation, preventing further chain growth by endwise polymerization resulting in lignin polymers with lower degree of polymerization. These results indicate that, for endwise polymerization in lignin synthesis, there exists a chemical control that may lay a significant role in determining the structure of lignin.

  6. Polymerization reactivity of sulfomethylated alkali lignin modified with horseradish peroxidase.

    PubMed

    Yang, Dongjie; Wu, Xiaolei; Qiu, Xueqing; Chang, Yaqi; Lou, Hongming

    2014-03-01

    Alkali lignin (AL) was employed as raw materials in the present study. Sulfomethylation was conducted to improve the solubility of AL, while sulfomethylated alkali lignin (SAL) was further polymerized by horseradish peroxidase (HRP). HRP modification caused a significant increase in molecular weight of SAL which was over 20 times. It was also found to increase the amount of sulfonic and carboxyl groups while decrease the amount of phenolic and methoxyl groups in SAL. The adsorption quantity of self-assembled SAL film was improved after HRP modification. Sulfonation and HRP modification were mutually promoted. The polymerization reactivity of SAL in HRP modification was increased with its sulfonation degree. Meanwhile, HRP modification facilitated SAL's radical-sulfonation reaction. PMID:24534439

  7. Biosynthesis and incorporation of side-chain-truncated lignin monomers to reduce lignin polymerization and enhance saccharification.

    PubMed

    Eudes, Aymerick; George, Anthe; Mukerjee, Purba; Kim, Jin S; Pollet, Brigitte; Benke, Peter I; Yang, Fan; Mitra, Prajakta; Sun, Lan; Cetinkol, Ozgül P; Chabout, Salem; Mouille, Grégory; Soubigou-Taconnat, Ludivine; Balzergue, Sandrine; Singh, Seema; Holmes, Bradley M; Mukhopadhyay, Aindrila; Keasling, Jay D; Simmons, Blake A; Lapierre, Catherine; Ralph, John; Loqué, Dominique

    2012-06-01

    Lignocellulosic biomass is utilized as a renewable feedstock in various agro-industrial activities. Lignin is an aromatic, hydrophobic and mildly branched polymer integrally associated with polysaccharides within the biomass, which negatively affects their extraction and hydrolysis during industrial processing. Engineering the monomer composition of lignins offers an attractive option towards new lignins with reduced recalcitrance. The presented work describes a new strategy developed in Arabidopsis for the overproduction of rare lignin monomers to reduce lignin polymerization degree (DP). Biosynthesis of these 'DP reducers' is achieved by expressing a bacterial hydroxycinnamoyl-CoA hydratase-lyase (HCHL) in lignifying tissues of Arabidopsis inflorescence stems. HCHL cleaves the propanoid side-chain of hydroxycinnamoyl-CoA lignin precursors to produce the corresponding hydroxybenzaldehydes so that plant stems expressing HCHL accumulate in their cell wall higher amounts of hydroxybenzaldehyde and hydroxybenzoate derivatives. Engineered plants with intermediate HCHL activity levels show no reduction in total lignin, sugar content or biomass yield compared with wild-type plants. However, cell wall characterization of extract-free stems by thioacidolysis and by 2D-NMR revealed an increased amount of unusual C₆C₁ lignin monomers most likely linked with lignin as end-groups. Moreover the analysis of lignin isolated from these plants using size-exclusion chromatography revealed a reduced molecular weight. Furthermore, these engineered lines show saccharification improvement of pretreated stem cell walls. Therefore, we conclude that enhancing the biosynthesis and incorporation of C₆C₁ monomers ('DP reducers') into lignin polymers represents a promising strategy to reduce lignin DP and to decrease cell wall recalcitrance to enzymatic hydrolysis. PMID:22458713

  8. A Comparative Study of Enzymatically and Photochemically Polymerized Artificial Lignin Supramolecular Structures Using Environmental Scanning Electron Microscopy.

    PubMed

    Micic; Jeremic; Radotic; Leblanc

    2000-11-01

    Environmental scanning electron microscopy images of the self-assembled structures of enzymatically (DHP) and photochemically polymerized (PCP) artificial lignin are herein presented. Differences in the structural organization between DHP and PCP polymer at the supramolecular level were reported. Based on topological information, we proposed a hypothesis about possible new physiological roles of lignin in live plant cells and the ecological significance of possible in-vivo photochemical lignin polymerization. Copyright 2000 Academic Press. PMID:11082264

  9. LIGNINS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lignins are complex and irregular polymers occurring in the cell walls of vascular plants. An understanding of their nature is evolving as a result of detailed structural investigations aided by recent improvements in analytical methodology and the availability of lignin-biosynthetic-pathway mutants...

  10. BOTANICAL ASPECTS OF ACIDIC PRECIPITATION

    EPA Science Inventory

    Acidic precipitation can be characterized as wet or frozen atmospheric deposition with a hydrogen ion concentration greater than 2.5 microequivalents liter-1. Acidic precipitation is perceived as a significant air pollution problem derived chiefly from combustion of fossil fuels,...

  11. Acid precipitation in historical perspective

    SciTech Connect

    Cowling, E.B.

    1982-02-01

    The history of acid precipitation is traced from the first awareness of the problem in the mid-17th century to the present. An outline of the National Acid Precipitation Assessment program is also given, and the author makes recommendations for future research. (JMT)

  12. Integration of lignin and acrylic monomers towards grafted copolymers by free radical polymerization.

    PubMed

    Liu, Xiaohuan; Xu, Yuzhi; Yu, Juan; Li, Shouhai; Wang, Jifu; Wang, Chunpeng; Chu, Fuxiang

    2014-06-01

    Three kinds of acrylic monomers (2,2,3,4,4,4-hexafluorobutyl methacrylate (HFBMA), methyl methacrylate (MMA) and butyl acrylate (BA)) were utilized to modify the lignin (BBL) by "grafting from" free radical polymerization (FRP), respectively. Calcium chloride/hydrogen peroxide (CaCl2/H2O2) was used as initiator. Effects of monomer type and concentration, initiator concentration and polymerization time on grafting from BBL were studied. Grafting of poly (acrylic monomers) onto BBL was verified by the following characterizations and this synthesis method was found to be high efficient and selective for grafting polymerization of BBL. The presence of the BBL moiety in the backbone also resulted in higher glass transition temperature compared with the homopolymer of each monomer, and some modified copolymers also improved its thermal stability. All modifications made BBL more hydrophobic and the static contact angles of these modified copolymers were above 80°. XPS analysis revealed that the surface of these modified BBL copolymers were dominated by acrylate monomer moiety. Additionally, the BBL-g-PBA copolymers can be used as dispersion modifiers in PLA-based materials to enhance UV absorption. PMID:24742785

  13. Polymerization of guaiacol by lignin-degrading manganese peroxidase from Bjerkandera adusta in aqueous organic solvents.

    PubMed

    Iwahara, K; Honda, Y; Watanabe, T; Kuwahara, M

    2000-07-01

    Lignin-degrading manganese (II) peroxidase (MnP) purified from the culture of a wood-rotting basidiomycete, Bjerkandera adusta, was used in the polymerization of guaiacol. MnP was found to catalyze polymerization of guaiacol in 50% aqueous acetone, dimethyl formamide, methanol, ethanol, dioxane, acetonitrile, ethylene glycol and methylcellosolve. Maximum yield of polyguaiacol was achieved in 50% aqueous acetone. The weight average molecular weight (Mw) of the polymer was estimated to be 30,300 by gel permeation chromatography. However, matrix-assisted laser desorption ionization time of flight mass spectroscopy (MALDI-TOF-MS) analysis gave a more reliable Mw of 1,690. IR, 13C-NMR, MALDI-TOF-MS and pyrolysis GC-MS analyses showed the presence of C-C and C-O linkages and quinone structure in polyguaiacol. It was also indicated that polyguaiacol has a methoxy-phenyl group as the terminal moiety. This suggests that polyguaiacol is a branched polymer in which guaiacol units are cross-linked at the phenolic group. Thermal gravimetric and differential scanning calorimetric analyses were also carried out. MnP also catalyzed the polymerization of o-cresol, 2,6-dimethoxyphenol and other phenolic compounds and aromatic amines. Mw of these polymers ranged from around 1,000 to 1,500. PMID:10952012

  14. Lignin removal enhancement from prehydrolysis liquor of kraft-based dissolving pulp production by laccase-induced polymerization.

    PubMed

    Wang, Qiang; Jahan, M Sarwar; Liu, Shanshan; Miao, Qingxian; Ni, Yonghao

    2014-07-01

    Lignin removal is essential for value-added utilization of hemicelluloses and acetic acid present in the prehydrolysis liquor (PHL) of a kraft-based hardwood dissolving pulp production. In this paper, a novel process concept, consisting of laccase-induced lignin polymerization, followed by filtration/flocculation, was developed to enhance the lignin removal. The results showed that the lignin removal increased from 11% to 46-61% at laccase concentration of 1-4 U mL(-1). The GPC results showed that the molecular weight of the lignin from the laccase treated PHL was increased by 160% in comparison with the original one. The subsequent flocculation using singular Poly-DADMAC system or dual polymer system of Poly-DADMAC/CPAM can further remove 10-15% lignin. The concentrations of hemicelluloses and acetic acid were negligibly affected during the laccase treatment, while flocculation caused 12-15% of total sugar loss. Additionally, the process incorporates this new concept into the kraft-based dissolving pulp production process was proposed. PMID:24865327

  15. Preparation of porous carbons from polymeric precursors modified with acrylated kraft lignin

    NASA Astrophysics Data System (ADS)

    Sobiesiak, M.

    2016-04-01

    The presented studies concern the preparation of porous carbons from a BPA.DA-St polymer containing acrylated kraft lignin as a monomer. The porous polymeric precursor in the form of microspheres was synthesized in suspension polymerization process. Next samples of the polymer were impregnated with acetic acid or aqueous solution of acetates (potassium or ammonia), dried and carbonised in nitrogen atmosphere at 450°C. After carbonization microspherical shape of the materials was remained, that is desired feature for potential application in chromatography or SPE technique. Chemical and textural properties of the porous carbon adsorbents were characterized using infrared spectroscopy (ATR-FTIR), thermogravimetry analyses with mass spectrometry of released gases (TG-MS) and nitrogen sorption experiments. The presented studies revealed the impregnation is useful method for development of porous structure of carbonaceous materials. The highest values of porous structure parameters were obtained when acetic acid and ammonium acetate were used as impregnating substances. On the surface of the materials oxygen functional groups are present that is important for specific interactions during sorption processes. The highest contents of functionalities were observed for carbon BPA.DA-St-LA-C-AcNH4.

  16. Syringyl Methacrylate, a Hardwood Lignin-Based Monomer for High-Tg Polymeric Materials

    PubMed Central

    2016-01-01

    As viable precursors to a diverse array of macromolecules, biomass-derived compounds must impart wide-ranging and precisely controllable properties to polymers. Herein, we report the synthesis and subsequent reversible addition–fragmentation chain-transfer polymerization of a new monomer, syringyl methacrylate (SM, 2,6-dimethoxyphenyl methacrylate), that can facilitate widespread property manipulations in macromolecules. Homopolymers and heteropolymers synthesized from SM and related monomers have broadly tunable and highly controllable glass transition temperatures ranging from 114 to 205 °C and zero-shear viscosities ranging from ∼0.2 kPa·s to ∼17,000 kPa·s at 220 °C, with consistent thermal stabilities. The tailorability of these properties is facilitated by the controlled polymerization kinetics of SM and the fact that one vs two o-methoxy groups negligibly affect monomer reactivity. Moreover, syringol, the precursor to SM, is an abundant component of depolymerized hardwood (e.g., oak) and graminaceous (e.g., switchgrass) lignins, making SM a potentially sustainable and low-cost candidate for tailoring macromolecular properties. PMID:27213117

  17. Acid Precipitation: Causes and Consequences.

    ERIC Educational Resources Information Center

    Babich, Harvey; And Others

    1980-01-01

    This article is the first of three articles in a series on the acid rain problem in recent years. Discussed are the causes of acid precipitation and its consequences for the abiotic and biotic components of the terrestrial and aquatic ecosystems, and for man-made materials. (Author/SA)

  18. Lignin nanoparticle synthesis

    DOEpatents

    Dirk, Shawn M.; Cicotte, Kirsten Nicole; Wheeler, David R.; Benko, David A.

    2015-08-11

    A method including reducing a particle size of lignin particles to an average particle size less than 40 nanometers; after reducing the particle size, combining the lignin particles with a polymeric material; and forming a structure of the combination. A method including exposing lignin to a diazonium precursor including a functional group; modifying the lignin by introducing the functional group to the lignin; and combining the modified lignin with a polymeric material to form a composite. An apparatus including a composite of a polymer and lignin wherein the lignin has an average particle size less than 100 micrometers.

  19. Strategies for the Conversion of Lignin to High-Value Polymeric Materials: Review and Perspective.

    PubMed

    Upton, Brianna M; Kasko, Andrea M

    2016-02-24

    The majority of commodity plastics and materials are derived from petroleum-based chemicals, illustrating the strong dependence on products derived from non-renewable energy sources. As the most accessible, renewable form of carbon (in comparison to CO2), lignocellulosic biomass (defined as organic matter available on a renewable basis) has been acknowledged as the most logical carbon-based feedstock for a variety of materials such as biofuels and chemicals. This Review focuses on methods developed to synthesize polymers derived from lignin, monolignols, and lignin-derived chemicals. Major topics include the structure and processing of lignocellulosic biomass to lignin, polymers utilizing lignin as a macromonomer, synthesis of monomers and polymers from monolignols, and polymers from lignin-derived chemicals, such as vanillin. PMID:26654678

  20. Lignin-solubilizing ability of actinomycetes isolated from termite (Termitidae) gut. [Streptomyces viridosporus

    SciTech Connect

    Pasti, M.B.; Crawford, D.L. ); Pometto, A.L., III ); Nuti, M.P. )

    1990-07-01

    The lignocellulose-degrading abilities of 11 novel actinomycete strains isolated from termite gut were determined and compared with that of the well-characterized actinomycete, Streptomyces viridosporus T7A. Lignocellulose bioconversion was followed by (i) monitoring the degradation of ({sup 14}C)lignin- and ({sup 14}C)cellulose-labeled phloem of Abies concolor to {sup 14}CO{sub 2} and {sup 14}C-labeled water-soluble products, (ii) determining lignocellulose, lignin, and carbohydrate losses resulting from growth on a lignocellulose substrate prepared from corn stalks (Zea mays), and (iii) quantifying production of a water-soluble lignin degradation intermediate (acid-precipitable polymeric lignin). Of the assays used, total lignocellulose weight loss was most useful in determining overall bioconversion ability but not in identifying the best lignin-solubilizing strains. A screening procedure based on {sup 14}CO{sub 2} evolution from ({sup 14}C-lignin)lignocellulose combined with measurement of acid-precipitable polymeric lignin yield was the most effective in identifying lignin-solubilizing strains. For the termite gut strains, the pH of the medium showed no increase after 3 weeks of growth on lignocellulose. This is markedly different from the pattern observed with S. viridosporus T7A, which raises the medium pH considerably. Production of extracellular peroxidases by the 11 strains and S. viridosporus T7A was followed for 5 days in liquid cultures. On the basis of an increase of specific peroxidase activity in the presence of lignocellulose in the medium, the actinomycetes could be placed into the same three groups.

  1. Acid Precipitation and the Forest Ecosystem

    ERIC Educational Resources Information Center

    Dochinger, Leon S.; Seliga, Thomas A.

    1975-01-01

    The First International Symposium on Acid Precipitation and the Forest Ecosystem dealt with the potential magnitude of the global effects of acid precipitation on aquatic ecosystems, forest soils, and forest vegetation. The problem is discussed in the light of atmospheric chemistry, transport, and precipitation. (Author/BT)

  2. Compositional Analysis of Lignin in Bioenergy Crops and De-polymerization via Pretreatment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lignin is a complex phenylpropanoid polymer derived from enzyme mediated radical coupling of coniferyl, sinapyl and coumaryl alcohols with main functions to impart strength to plant cell wall, transport water and provide defense against pathogens. Physical, chemical and biological degradation of ce...

  3. Acid precipitation and human health: Final report

    SciTech Connect

    Hoffman, S.

    1989-08-01

    This report, written for environmental managers in electric utilities, reviews potential indirect human health effects of acid precipitation. Possible exposure routes and materials examined in this review include drinking water contamination (aluminum and mercury), corrosion of metals (lead, cadmium, arsenic, selenium, copper, and zinc) and asbestos from water piping, bioaccumulation of mercury and other metals in fish and game, and uptake of mobilized metals in crops. No direct effects (e.g., skin or eye irritation) of human exposure to acid precipitation have been identified, and air pollutant impacts on health are not included in this review, because these pollutants are acid precipitation precursors, not acid precipitation per se. The literature is summarized, presenting results from researchers' studies to support their conclusions. The review discusses potential acid precipitation impacts on metal levels in drinking water and food, summarizes the health effects of ingestion of these materials, and identifies areas of needed research. Metal-metal interactions in humans that may be related to acid precipitation are identified. Current research programs and planned assessments of the indirect human health effects of acid precipitation are summarized. 136 refs., 38 figs., 17 tabs

  4. EFFECTS OF ACID PRECIPITATION ON PLANT DISEASES

    EPA Science Inventory

    Most plant diseases consist of delicate interactions between higher plants and microorganisms. Acidic precipitation represents an environmental stress that has been shown to affect expected development of some diseases and similar phenomena under experimental conditions. From the...

  5. Acid precipitation: basic principles and ecological consequences

    SciTech Connect

    Cowling, E.B.; Davey, C.B.

    1981-08-01

    The pulp and paper industry is involved with both the cause and effects of acid precipitation. Although significant quantities of desirable plant nutrients (nitrogen and sulfur) are added to the forest system by precipitation, the acidity and its detrimental effects may outweigh the benefits. Damage to the ecosystem is most likely to occur when major inputs of acid precipitation coincide with sensitive stages of a life form (such as fish eggs and larvae), and in poorly buffered, noncalcareous soils and rocks. Biological effects of acid precipitation have been demonstrated - necrotic lesions on foliage, nutrient loss from foliar organs, reduced resistance to pathogens, accelerated erosion of waxes on leaf surfaces, reduced rates of decomposition of leaf litter, inhibited formation of terminal buds, increased seedling mortality, and heavy metal accumulation. Soil microbiological processes such as nitrogen fixation, mineralization of forest litter, and nitrification of ammonium compounds are inhibited, the degree depending on degree of cultivation and soil buffering capacity. Water quality is impacted by contact with vegetation, soil, and bedrock. Acid precipitation mobilizes cations, especially the toxic Al, Mn, and Zn, and nutrients, K, Ca, and Mg. 25 references.

  6. Species difference in reactivity to lignin-like enzymatically polymerized polyphenols on interferon-γ synthesis and involvement of interleukin-2 production in mice.

    PubMed

    Yamanaka, Daisuke; Ishibashi, Ken-Ichi; Adachi, Yoshiyuki; Ohno, Naohito

    2016-09-01

    Recent studies have revealed that lignin-like polymerized polyphenols can activate innate immune systems. In this study, we aimed to evaluate whether these polymerized polyphenols could activate leukocytes from different murine strains. Splenocytes from 12 mouse strains were investigated. Our results revealed species differences in reactivity to phenolic polymers on interferon-γ (IFN-γ) release. Mice that possessed the H2(a) or H2(k) haplotype antigens were the highly responsive strains. To clarify these different points in soluble factors, multiplex cytokine profiling analysis was carried out and we identified interleukin (IL)-2 as a key molecule for IFN-γ induction by polymerized polyphenols. Furthermore, inhibition of IL-2 and IL-2Rα by neutralizing antibodies significantly decreased cytokine production in the highly responsive mice strains. Our results indicate that species difference in reactivity to phenolic polymers is mediated by adequate release of IL-2 and its receptor, IL-2Rα. PMID:27376855

  7. Acid precipitation. (Latest citations from the Compendex database). Published Search

    SciTech Connect

    Not Available

    1993-06-01

    The bibliography contains citations concerning the causes, effects, sources, and controls of acid precipitation and acidification. Techniques and technology for measurement and analysis of acid precipitation are considered. (Contains 250 citations and includes a subject term index and title list.)

  8. Acid precipitation. (Latest citations from Pollution abstracts). Published Search

    SciTech Connect

    Not Available

    1994-03-01

    The bibliography contains citations concerning the research of acid precipitation, and the resultant acidification of land and water. Topics include composition, causes, effects, sources, measurements, and controls of acid precipitation. Worldwide geographical distribution of acid precipitation and acidification are covered. (Contains 250 citations and includes a subject term index and title list.)

  9. Acid precipitation. (Latest citations from Pollution Abstracts database). Published Search

    SciTech Connect

    Not Available

    1993-09-01

    The bibliography contains citations concerning the research of acid precipitation, and the resultant acidification of land and water. Topics include composition, causes, effects, sources, measurements, and controls of acid precipitation. Worldwide geographical distribution of acid precipitation and acidification are covered. (Contains 250 citations and includes a subject term index and title list.)

  10. Primer on acid precipitation. A killing rain: the global threat of acid precipitation

    SciTech Connect

    Pawlick, T.

    1984-01-01

    This article reviews the book A Killing Rain: The Global Threat of Acid Precipitation by Thomas Pawlick which presents an overview of the problems associated with acid rain. The book covers the effects of acid rain on aquatic ecosystems, forests materials, and agriculture. It also deals with abatement technologies and sociopolitical topics associated with acid rain.

  11. Effects of acid precipitation on Daphnia magna

    SciTech Connect

    Parent, S.; Cheetham, R.D.

    1980-08-01

    Pollutants derived from fossil fuel combustion and precipitated from the atmosphere have substantially increased in the past decades. These materials, precipitated in such industrialized areas as southeastern Canada, have caused considerable alterations in aquatic ecosystems. Precipitation over most of the eastern United States is presently 10 to 500 times more acidic than is natural. Most affected aquatic ecosystems contain oligotrophic waters in regions of thin poorly buffered soils. Zooplankton are an important link in food chains of aquatic ecosystems and their disappearance or decline could drastically affect trophic relationships. Declines in zooplankton density in response to acid precipitation have been reported and short term survival of Daphnia pulex between pH 4.3 and 10.4; however, its potential for reproduction was limited to a fairly narrow range. Anderson (1944) noted the advantages of using daphnia as test organisms, and concluded that Daphnia magna was representative of other abundant zooplankton in sensitivity to toxic substances.

  12. Through Lignin Biodegradation to Lignin-based Plastics

    NASA Astrophysics Data System (ADS)

    Wang, Yun-Yan

    The consequences of strong noncovalent intermolecular interactions between oligomeric and/or polymeric lignin components are encountered during enzyme-catalyzed lignin degradation and in the properties of lignin-based plastics. A new chapter in the 30-year quest for functional lignin-depolymerizing enzymes has been opened. The lignin-degrading capacity of the flavin-dependent monooxygenase, salicylate hydroxylase acting as a putative lignin depolymerase, has been characterized using a water-soluble native softwood lignin substrate under mildly acidic aqueous conditions. When macromolecular lignins undergo lignin-depolymerase catalyzed degradation, the cleaved components tend to associate with one another, or with nearby associated lignin complexes, through processes mediated by the enzyme acting in a non-catalytic capacity. As a result, the radius of gyration (Rg) falls rapidly to approximately constant values, while the weight-average molecular weight (Mw) of the substrate rises more slowly to an extent dependent on enzyme concentration. Xylanase, when employed in an auxiliary capacity, is able to facilitate dissociation of the foregoing complexes through its interactions with the lignin depolymerase. The flavin-dependent lignin depolymerase must be reduced before reaction with oxygen can occur to form the hydroperoxy intermediate that hydroxylates the lignin substrate prior to cleavage. In the absence of the cofactor, NADH, the necessary reducing power can be provided (albeit more slowly) by the lignin substrate itself. Under such conditions, a simultaneous decrease in R g and Mw is initially observed during the enzymatic process through which the lignin is cleaved. The partially degraded product-lignins arising from lignin depolymerase activity can be readily converted into polymeric materials with mechanical properties that supersede those of polystyrene. Methylation and blending of ball-milled softwood lignins with miscible low-Tg polymers, or simple low

  13. Acid precipitation. (Latest citations from Pollution Abstracts). Published Search

    SciTech Connect

    Not Available

    1992-06-01

    The bibliography contains citations concerning the wet and dry precipitation of acid, and the resultant acidification of land and water. Topics include composition, causes, effects, sources, measurements, and controls of acid precipitation. Some attention is focused upon the worldwide geographical distribution of acid precipitation and acidification. (Contains 250 citations and includes a subject term index and title list.)

  14. EFFECTS OF ACID PRECIPITATION ON SOIL LEACHATE QUALITY: COMPUTER CALCULATIONS

    EPA Science Inventory

    The multipurpose computer program GEOCHEM was employed to calculate the equilibrium speciation in twenty-three examples of acid precipitation from New Hampshire, New York, and Maine, and in the same number of mixtures of acid precipitation with minerals characteristic of soils in...

  15. Lignin-Based Thermoplastic Materials.

    PubMed

    Wang, Chao; Kelley, Stephen S; Venditti, Richard A

    2016-04-21

    Lignin-based thermoplastic materials have attracted increasing interest as sustainable, cost-effective, and biodegradable alternatives for petroleum-based thermoplastics. As an amorphous thermoplastic material, lignin has a relatively high glass-transition temperature and also undergoes radical-induced self-condensation at high temperatures, which limits its thermal processability. Additionally, lignin-based materials are usually brittle and exhibit poor mechanical properties. To improve the thermoplasticity and mechanical properties of technical lignin, polymers or plasticizers are usually integrated with lignin by blending or chemical modification. This Review attempts to cover the reported approaches towards the development of lignin-based thermoplastic materials on the basis of published information. Approaches reviewed include plasticization, blending with miscible polymers, and chemical modifications by esterification, etherification, polymer grafting, and copolymerization. Those lignin-based thermoplastic materials are expected to show applications as engineering plastics, polymeric foams, thermoplastic elastomers, and carbon-fiber precursors. PMID:27059111

  16. RAINFALL SIMULATOR FOR LABORATORY USE IN ACIDIC PRECIPITATION STUDIES

    EPA Science Inventory

    A rainfall simulator, developed on the principle of droplet formation from needle tips, is described. The simulator is designed for laboratory experimentation to examine the effects of acidic precipitation on terrestrial plants. The system offers sufficient flexibility to simulat...

  17. Lignin valorization: improving lignin processing in the biorefinery.

    PubMed

    Ragauskas, Arthur J; Beckham, Gregg T; Biddy, Mary J; Chandra, Richard; Chen, Fang; Davis, Mark F; Davison, Brian H; Dixon, Richard A; Gilna, Paul; Keller, Martin; Langan, Paul; Naskar, Amit K; Saddler, Jack N; Tschaplinski, Timothy J; Tuskan, Gerald A; Wyman, Charles E

    2014-05-16

    Research and development activities directed toward commercial production of cellulosic ethanol have created the opportunity to dramatically increase the transformation of lignin to value-added products. Here, we highlight recent advances in this lignin valorization effort. Discovery of genetic variants in native populations of bioenergy crops and direct manipulation of biosynthesis pathways have produced lignin feedstocks with favorable properties for recovery and downstream conversion. Advances in analytical chemistry and computational modeling detail the structure of the modified lignin and direct bioengineering strategies for future targeted properties. Refinement of biomass pretreatment technologies has further facilitated lignin recovery, and this coupled with genetic engineering will enable new uses for this biopolymer, including low-cost carbon fibers, engineered plastics and thermoplastic elastomers, polymeric foams, fungible fuels, and commodity chemicals. PMID:24833396

  18. Lignin Valorization: Improving Lignin Processing in the Biorefinery

    SciTech Connect

    Ragauskas, Arthur; Beckham, Gregg; Biddy, Mary J; Chandra, Richard; Chen, Fang; Davis, Dr. Mark F.; Davison, Brian H; Dixon, Richard; Gilna, Paul; Keller, Martin; Langan, Paul; Naskar, Amit K; Saddler, Jack N; Tschaplinski, Timothy J; Tuskan, Gerald A; Wyman, Charles E,; Harber, Karen S

    2014-01-01

    Research and development activities directed toward commercial production of cellulosic ethanol have created the opportunity to dramatically increase the transformation of lignin to value-added products. Here we highlight recent advances in this lignin valorization effort. Discovery of genetic variants in native populations of bioenergy crops and direct manipulation of biosynthesis pathways have produced lignin feedstocks with favorable properties for recovery and downstream conversion. Advances in analytical chemistry and computational modeling detail the structure of the modified lignin and direct bioengineering strategies for future targeted properties. Refinement of biomass pretreatment technologies has further facilitated lignin recovery, and this coupled with genetic engineering will enable new uses for this biopolymer, including low-cost carbon fibers, engineered plastics and thermoplastic elastomers, polymeric foams, fungible fuels, and commodity chemicals.

  19. Acid Precipitation Awareness Curriculum Materials in the Life Sciences.

    ERIC Educational Resources Information Center

    Stubbs, Harriett S.

    1983-01-01

    Provides an outline of course content for acid precipitation and two acid rain activities (introduction to pH and effects of acid rain on an organism). Information for obtaining 20 additional activities as well as an information packet containing booklets, pamphlets, and articles are also provided. (JN)

  20. Teacher's Resource Guide on Acidic Precipitation with Laboratory Activities.

    ERIC Educational Resources Information Center

    Barrow, Lloyd H.

    The purpose of this teacher's resource guide is to help science teachers incorporate the topic of acidic precipitation into their curricula. A survey of recent junior high school science textbooks found a maximum of one paragraph devoted to the subject; in addition, none of these books had any related laboratory activities. It was on the basis of…

  1. MODELING IMPACTS OF ACID PRECIPITATION FOR NORTHEASTERN MINNESOTA

    EPA Science Inventory

    The acidification of lakes and streams due to acid precipitation has been documented in southern Sweden and Norway, the northeastern United States and southern Ontario. Geochemistry and regional lithology are recognized to be important factors in the susceptibility of lake ecosys...

  2. NAPAP (National Acid Precipitation Assessment Program) results on acid rain

    SciTech Connect

    Not Available

    1990-06-01

    The National Acid Precipitation Assessment Program (NAPAP) was mandated by Congress in 1980 to study the effects of acid rain. The results of 10 years of research on the effect of acid deposition and ozone on forests, particularly high elevation spruce and fir, southern pines, eastern hardwoods and western conifers, will be published this year.

  3. PROBABLE EFFECTS OF ACID PRECIPITATION ON PENNSYLVANIA WATERS

    EPA Science Inventory

    The purpose of this project was to search for and identify any trends in water chemistry and fish communities in Pennsylvania waters which would indicate that acid precipitation was affecting them adversely. No new data collection was to be included. Five existing data bases, inc...

  4. Preparation and Analysis of Biomass Lignins

    SciTech Connect

    Compere, A L; Griffith, William {Bill} L

    2009-01-01

    Lignin, comprised primarily of three randomly polymerized phenylpropenyl monomers, is, arguably, the second most common organic molecule on earth. In current biorefinery applications, lignin is burned, usually in concentrated pulping or hydrolysis liquor, as a source of process steam and both internal and exported electricity. The aromatic content of lignin makes it a potentially attractive feedstock for highly-valued aromatic chemicals, polymers, and carbon products (graphite, activated carbon, and carbon fiber). Revenue from production of lignin-based chemicals could play a major role in biorefinery profitability if cost-effective methods for lignin separation and purification can be developed. This article presents descriptions of methods for assessing and purifying biorefinery lignins so that they can be evaluated for use as feedstocks for production of chemical products. Areas covered are: 1) initial evaluations of as-received lignin samples (visual, microscopic, separable organics), 2) analysis of common contaminants (bulk and filterable ash and particulate contaminants in liquid and dry lignin samples), 3) preparation of lignins for experimental use as chemical feedstocks (prefiltration, filtration using bench-scale chemical apparatus and larger scale bag filters, one-step lignin precipitation, two-step carbohydrate and lignin precipitation, desalting of dry powdered or precipitated lignin, and lyophilization). These methods have been used successfully at bench-scale to produce the 1 50 kg amounts of wood and grass lignins typically required for bench-scale assessment as chemical feedstocks

  5. Preparation and Analysis of Biomass Lignins

    NASA Astrophysics Data System (ADS)

    Compere, Alicia L.; Griffith, William L.

    Lignin, comprised primarily of three randomly polymerized phenylpropenyl monomers, is, arguably, the second most common organic molecule on earth. In current biorefinery applications, lignin is burned, usually in concentrated pulping or hydrolysis liquor, as a source of process steam and both internal and exported electricity. The aromatic content of lignin makes it a potentially attractive feedstock for high-value aromatic chemicals, polymers, and carbon products (graphite, activated carbon, and carbon fiber). Revenue from production of lignin-based chemicals could play a major role in biorefinery profitability if cost-effective methods for lignin separation and purification can be developed. This chapter presents descriptions of methods for assessing and purifying biorefinery lignins so that they can be evaluated for use as feedstock for production of chemical products. Areas covered are: (1) initial evaluations of as-received lignin samples (visual, microscopic, separable organics); (2) analysis of common contaminants (bulk and filterable ash and particulate contaminants in liquid and dry lignin samples); (3) preparation of lignins for experimental use as chemical feedstock (prefiltration, filtration using bench-scale chemical apparatus and larger scale bag filters, one-step lignin precipitation, two-step carbohydrate and lignin precipitation, desalting of dry powdered or precipitated lignin, and lyophilization). These methods have been used successfully at the bench scale to produce the 1-50 kg amounts of wood and grass lignins typically required for bench-scale assessment as chemical feedstocks.

  6. Characterisation of Dyp-type peroxidases from Pseudomonas fluorescens Pf-5: Oxidation of Mn(II) and polymeric lignin by Dyp1B.

    PubMed

    Rahmanpour, Rahman; Bugg, Timothy D H

    2015-05-15

    Members of the DyP family of peroxidases in Gram-positive bacteria have recently been shown to oxidise Mn(II) and lignin model compounds. Gram-negative pseudomonads, which also show activity for lignin oxidation, also contain dyp-type peroxidase genes. Pseudomonas fluorescens Pf-5 contains three dyp-type peroxidases (35, 40 and 55kDa), each of which has been overexpressed in Escherichia coli, purified, and characterised. Each of the three enzymes shows activity for oxidation of phenol substrates, but the 35kDa Dyp1B enzyme also shows activity for oxidation of Mn(II) and Kraft lignin. Treatment of powdered lignocellulose with Dyp1B in the presence of Mn(II) and hydrogen peroxide leads to the release of a low molecular weight lignin fragment, which has been identified by mass spectrometry as a β-aryl ether lignin dimer containing one G unit and one H unit bearing a benzylic ketone. A mechanism for release of this fragment from lignin oxidation is proposed. PMID:25558792

  7. Impact of effects of acid precipitation on toxicity of metals.

    PubMed Central

    Nordberg, G F; Goyer, R A; Clarkson, T W

    1985-01-01

    Acid precipitation may increase human exposure to several potentially toxic metals by increasing metal concentrations in major pathways to man, particularly food and water, and in some instances by enhancing the conversion of metal species to more toxic forms. Human exposures to methylmercury are almost entirely by way of consumption of fish and seafood. In some countries, intakes by this route may approach the levels that can give rise to adverse health effects for population groups with a high consumption of these food items. A possible increase in methylmercury concentrations in fish from lakes affected by acid precipitation may thus be of concern to selected population groups. Human exposures to lead reach levels that are near those associated with adverse health effects in certain sensitive segments of the general population in several countries. The possibility exists that increased exposures to lead may be caused by acid precipitation through a mobilization of lead from soils into crops. A route of exposure to lead that may possibly be influenced by acid precipitation is an increased deterioration of surface materials containing lead and a subsequent ingestion by small children. A similar situation with regard to uptake from food exists for cadmium (at least in some countries). Human metal exposures via drinking water may be increased by acid precipitation. Decreasing pH increases corrosiveness of water enhancing the mobilization of metal salts from soil; metallic compounds may be mobilized from minerals, which may eventually reach drinking water. Also, the dissolution of metals (Pb, Cd, Cu) from piping systems for drinking water by soft acidic waters of high corrosivity may increase metal concentrations in drinking water. Exposures have occasionally reached concentrations which are in the range where adverse health effects may be expected in otherwise healthy persons. Dissolution from piping systems can be prevented by neutralizing the water before

  8. Elicitor-Induced Spruce Stress Lignin (Structural Similarity to Early Developmental Lignins).

    PubMed Central

    Lange, B. M.; Lapierre, C.; Sandermann, H.

    1995-01-01

    Suspension cultures of Picea abies (L.) Karst released polymeric material into the culture medium when treated with an elicitor preparation from the spruce needle pathogen Rhizosphaera kalkhoffii. The presence of lignin (about 35%, w/w) was demonstrated by phloroglucinol/HCI reactivity and quantitation with thioglycolic acid. Carbohydrate (about 14%, w/w) and protein (about 32%, w/w) were also detected. Amino acid analysis revealed that hydroxyproline and proline predominated. Thioacidolysis and subsequent Raney nickel desulfurization allowed the analysis of lignin-building units and interunit bonds. Compared with spruce wood lignin, an approximately 20-fold higher relative amount of p-hydroxyphenyl units was determined. A high content of p-hydroxyphenyl units is typical for certain developmental lignins, such as conifer compression wood and middle lamella lignins, as well as all induced cell culture lignins so far analyzed. Cross-linkages of the pinoresinol type ([beta]-[beta]) in the excreted cell culture lignin were markedly increased, whereas [beta]-1 interunit linkages were decreased relative to spruce wood lignin. The amount and nature of cross-linkages were shown to be intermediate between those in wood lignin and in enzymatically prepared lignins. In summary, the elicitor-induced stress lignin was excreted as a lignin-extensin complex that closely resembled early developmental lignins. PMID:12228544

  9. Acidic precipitation: considerations for an air-quality standard

    SciTech Connect

    Evans, L.S.; Hendrey, G.R.; Stensland, G.J.; Johnson, D.W.; Francis, A.J.

    1980-01-01

    Acidic precipitation, wet or frozen deposition with a hydrogen ion concentration greatern than 2.5 ..mu..eq l/sup -1/ is a significant air pollution problem in the United States. The chief anions accounting for the hydrogen ions in rainfall are nitrate and sulfate. Agricultural systems are more likely to derive net nutritional benefits from increasing inputs of acidic rain than are forest systems when soils alone are considered. Agricultural soils may benefit because of the high N and S requirements of agricultural plants. Detrimental effects to forest soils may result if atmospheric H/sup +/ inputs significantly add to or exceed H/sup +/ production by soils. Acidification of fresh waters of southern Scandinavia, southwestern Scotland, southeastern Canada, and northeastern United States is caused by acid deposition. Areas of these regions in which this acidification occurs have in common, highly acidic precipitation with volume weighted mean annual H/sup +/ concentrations of 25 ..mu..eq l/sup -1/ or higher and slow weathering granitic or precambrian bedrock with thin soils deficient in minerals which would provide buffer capacity. Biological effects of acidification of fresh waters are detectable below pH 6.0. As lake and stream pH levels decrease below pH. 6.0, many species of plants, invertebrates, and vertebrates are progressively eliminated. Generally, fisheries are impacted below pH 5.0 and are completely destroyed below pH 4.8. There are few studies that document effects of acidic precipitation on terrestrial vegetation to establish an air quality standard. It must be demonstrated that current levels of precipitation acidity alone significantly injure terrestrial vegetation. In terms of documented damanges, current research indicates that establishing a standard for precipitation for the volume weighted annual H/sup +/ concentration at 25 ..mu..eq l/sup -1/ may protect the most sensitive areas from permanent lake acidification.

  10. Ten-year study on acid precipitation nears conclusion

    SciTech Connect

    Olem, H. )

    1990-04-01

    Results from the National Acid Precipitation Assessment Program (NAPAP) are discussed. Final results are contained in 26 state of the science reports. Seven of the reports provide information on acid rain and aquatic ecosystems. They describe the current state of acidic surface waters, watershed processes affecting surface water chemistry, historical evidence for surface water acidification, methods for forecasting future changes, and the response of acidic surface water to liming. Six areas of the country were found to be of special interest: southwest Adirondacks, New England, forested areas of the mid-Atlantic highlands, the Atlantic coastal plain, the northern Florida highlands, parts of northeastern Wisconsin and the Upper Peninsula of Michigan. Environmental effects, mitigation efforts and possible legislation are briefly discussed.

  11. Impact of acid precipitation on recreation and tourism in Ontario: an overview

    SciTech Connect

    Not Available

    1984-01-01

    The impacts of acid precipitation on fishing opportunities, waterfowl and moose hunting, water contact activities, and the perception of the environment in Ontario are analyzed. Economic effects and future research needs are also estimated and discussed. These questions have been examined by identifying the likely links between acidic precipitation and recreation and tourism, by developing estimates of the importance of aquatic-based recreation and tourism, by describing the current and estimated future effects of acid precipitation. 101 references, 9 figures, 19 tables.

  12. CCoAOMT suppression modifies lignin composition in Pinus radiata.

    PubMed

    Wagner, Armin; Tobimatsu, Yuki; Phillips, Lorelle; Flint, Heather; Torr, Kirk; Donaldson, Lloyd; Pears, Lana; Ralph, John

    2011-07-01

    A cDNA clone encoding the lignin-related enzyme caffeoyl CoA 3-O-methyltransferase (CCoAOMT) was isolated from a Pinus radiata cDNA library derived from differentiating xylem. Suppression of PrCCoAOMT expression in P. radiata tracheary element cultures affected lignin content and composition, resulting in a lignin polymer containing p-hydroxyphenyl (H), catechyl (C) and guaiacyl (G) units. Acetyl bromide-soluble lignin assays revealed reductions in lignin content of up to 20% in PrCCoAOMT-deficient transgenic lines. Pyrolysis-GC/MS and 2D-NMR studies demonstrated that these reductions were due to depletion of G-type lignin. Correspondingly, the proportion of H-type lignin in PrCCoAOMT-deficient transgenic lines increased, resulting in up to a 10-fold increase in the H/G ratio relative to untransformed controls. 2D-NMR spectra revealed that PrCCoAOMT suppression resulted in formation of benzodioxanes in the lignin polymer. This suggested that phenylpropanoids with an ortho-diphenyl structure such as caffeyl alcohol are involved in lignin polymerization. To test this hypothesis, synthetic lignins containing methyl caffeate or caffeyl alcohol were generated and analyzed by 2D-NMR. Comparison of the 2D-NMR spectra from PrCCoAOMT-RNAi lines and synthetic lignins identified caffeyl alcohol as the new lignin constituent in PrCCoAOMT-deficient lines. The incorporation of caffeyl alcohol into lignin created a polymer containing catechyl units, a lignin type that has not been previously identified in recombinant lignin studies. This finding is consistent with the theory that lignin polymerization is based on a radical coupling process that is determined solely by chemical processes. PMID:21426426

  13. Acid precipitation and ionic movements in Adironack forest soils

    SciTech Connect

    Mollitor, A.V.; Raynal, D.J.

    1982-01-01

    To examine potential effects of acid precipitation on forest soils in a hardwood and in a coniferous stand in the central Adirondacks of New York State, solution chemistry was studied in five strata of these ecosystems. Bulk precipitation, throughfall, and soil leachates were sampled and analyzed for pH, NO/sub 3/, SO/sub 4/, K, Ca, Mg, and Na. A subset of the samples were analyzed for Al. Organic anion concentrations were estimated from ionic charge balances. Concentrations of NO/sub 3/, H, and K in B horizon leachates were not significantly different than precipitation concentrations, while concentrations of SO/sub 4/, Ca, Mg, and Na in water leaving the sola were significantly greater than precipitation concentrations. Patterns of movement for most ions were similar for both study sites, but concentrations were generally greater in the conifer system. Cation leaching from the hardwood site appears about equally influenced by SO/sub 4/ and organic anion leaching. Sulfate and organic anion concentrations were greater in the conifer site but organic anion leaching dominated. Sulfate appears highly mobile in these soils. Chronic leaching by H/sub 2/SO/sub 4/ combined with internally generated organic acids may represent a threat to the nutrient status of many Adirondack forest soils.

  14. Rainfall simulator for laboratory use in acidic precipitation studies

    SciTech Connect

    Chevone, B.I.; Yang, Y.S.; Winner, W.E.; Storks-Cotter, I.; Long, S.J.

    1984-04-01

    A rainfall simulator, developed on the principle of droplet formation from needle tips, is described. The simulator is designed for laboratory experimentation to examine the effects of acidic precipitation on terrestrial plants. Droplet diameter can be varied from 2.5 to 3.4 mm with different gauge needles, and rainfall intensities from 0.50 to 1.25 cm h/sup -1/ can be attained by a variable speed peristaltic pump. Uniform distribution of rainfall was achieved by rotating the target area and by spacing needles, using an empirical cumulative probability distribution function, along eight radial tubular arms. Variation in rainfall distribution across a 1.2 m diameter circular target area was < 5%. Integrity of solution chemistry was maintained upon passage through the simulator with variations in cation concentrations < 10%, anion concentrations < 5% and pH < 0.2. The system offers sufficient flexibility to simulate a range of rainfall characteristics by varying needle diameter, changing pump speed and/or altering the number of radial arms on each unit.

  15. Bacterial extracellular lignin peroxidase

    DOEpatents

    Crawford, Donald L.; Ramachandra, Muralidhara

    1993-01-01

    A newly discovered lignin peroxidase enzyme is provided. The enzyme is obtained from a bacterial source and is capable of degrading the lignin portion of lignocellulose in the presence of hydrogen peroxide. The enzyme is extracellular, oxidative, inducible by lignin, larch wood xylan, or related substrates and capable of attacking certain lignin substructure chemical bonds that are not degradable by fungal lignin peroxidases.

  16. ''The control of lignin synthesis''

    SciTech Connect

    Carlson, John E.

    2005-04-07

    In this project we tested the hypothesis that regulation of the synthesis of lignin in secondary xylem cells in conifer trees involves the transport of glucosylated lignin monomers to the wall of xylem cells, followed by de-glucosylation in the cell wall by monolignol-specific glucosidase enzymes, which activates the monomers for lignin polymerization. The information we gathered is relevant to the fundamental understanding of how trees make wood, and to the applied goal of more environmentally friendly pulp and paper production. We characterized the complete genomic structure of the Coniferin-specific Beta-glucosidase (CBG) gene family in the conifers loblolly pine (Pinus taeda) and lodgepole pine (Pinus contorta), and partial genomic sequences were obtained in several other tree species. Both pine species contain multiple CBG genes which raises the possibility of differential regulation, perhaps related to the multiple roles of lignin in development and defense. Subsequent projects will need to include detailed gene expression studies of each gene family member during tree growth and development, and testing the role of each monolignol-specific glucosidase gene in controlling lignin content.

  17. Unravelling lignin formation and structure

    SciTech Connect

    Lewis, N.G. . Inst. of Biological Chemistry)

    1991-01-01

    During this study, we established that the Fagaceae exclusively accumulate Z-monolignois/glucosides, and not the E-isomers. Evidence for the presence of a novel E{yields}Z isomerse has been obtained. Our pioneering work in lignin biosynthesis and structure in situ has also progressed smoothly. We established the bonding environments of a woody angiosperm, Leucanea leucocephala, as well as wheat (T. aestivum) and tobacco (N. tabacum). A cell culture system from Pinus taeda was developed which seems ideal for investigating the early stages of lignification. These cultures excrete peroxidase isozymes, considered to be specifically involved in lignin deposition. We also studied the effect of the putative lignin-degrading enzyme, lignin peroxidase, on monolignols and dehydropolymerisates therefrom. In all cases, polymerization was observed, and not degradation; these polymers are identical to that obtained with horseradish peroxidases/H{sub 2}O{sub 2}. It seems inconceivable that these enzymes can be considered as being primarily responsible for lignin biodegradation.

  18. Boric acid precipitation following a cold-leg LOCA

    SciTech Connect

    Twogood, F.J. ); Strong, B.R. ); Lew, B.S. ); Kramer, C. )

    1993-01-01

    For a postulated cold-leg loss-of-coolant accident (LOCA) in a pressurized water reactor, borated water from the safety injection and recirculation systems is predicted to flow preferentially around the reactor pressure vessel (RPV) downcomer and out the rupture, bypassing the core. Flow to the core may therefore be limited to just the flow that is required to make up for boil-off in the core and to maintain an equal static head between the downcomer and core regions. Lacking any mixing of dilute injection water in the core, this would result in the accumulation of boron in the core region until saturation concentrations are reached and boric acid begins to precipitate out of solution. Boric acid precipitation is undesirable because it may interfere with long-term core cooling. Without a reliable estimate of reflux condensation, this time to precipitation establishes the minimum time for the initiation of hot-leg recirculation to flush the core and terminate boric acid concentration. This analysis estimates the boric acid concentration over time for the postulated conditions of a cold-leg LOCA in San Onofre nuclear generating station unit 1, including the explicit incorporation of the stored heat release from the RPV and structures discussed in a companion paper. Earlier analyses assumed that the RPV stored energy was released during the safety injection phase immediately after the LOCA. Recent analyses showed that a significant portion of this stored energy is released into the coolant after core safety injection and needs to be explicitly addressed.

  19. Direct interaction of lignin and lignin peroxidase from Phanerochaete chrysosporium.

    PubMed

    Johjima, T; Itoh, N; Kabuto, M; Tokimura, F; Nakagawa, T; Wariishi, H; Tanaka, H

    1999-03-01

    Binding properties of lignin peroxidase (LiP) from the basidiomycete Phanerochaete chrysosporium against a synthetic lignin (dehydrogenated polymerizate, DHP) were studied with a resonant mirror biosensor. Among several ligninolytic enzymes, only LiP specifically binds to DHP. Kinetic analysis revealed that the binding was reversible, and that the dissociation equilibrium constant was 330 microM. The LiP-DHP interaction was controlled by the ionization group with a pKa of 5.3, strongly suggesting that a specific amino acid residue plays a role in lignin binding. A one-electron transfer from DHP to oxidized intermediates LiP compounds I and II (LiPI and LiPII) was characterized by using a stopped-flow technique, showing that binding interactions of DHP with LiPI and LiPII led to saturation kinetics. The dissociation equilibrium constants for LiPI-DHP and LiPII-DHP interactions were calculated to be 350 and 250 microM, and the first-order rate constants for electron transfer from DHP to LiPI and to LiPII were calculated to be 46 and 16 s-1, respectively. These kinetic and spectral studies strongly suggest that LiP is capable of oxidizing lignin directly at the protein surface by a long-range electron transfer process. A close look at the crystal structure suggested that LiP possesses His-239 as a possible lignin-binding site on the surface, which is linked to Asp-238. This Asp residue is hydrogen-bonded to the proximal His-176. This His-Asp...proximal-His motif would be a possible electron transfer route to oxidize polymeric lignin. PMID:10051582

  20. Structure of Brewer's Spent Grain Lignin and Its Interactions with Gut Microbiota in Vitro.

    PubMed

    Ohra-aho, Taina; Niemi, Piritta; Aura, Anna-Marja; Orlandi, Marco; Poutanen, Kaisa; Buchert, Johanna; Tamminen, Tarja

    2016-02-01

    Lignin is part of dietary fiber, but its conversion in the gastrointestinal tract is not well understood. The aim of this work was to obtain structural information on brewer's spent grain (BSG) lignin and to understand the behavior of the polymeric part of lignin exposed to fecal microbiota. The original BSG and different lignin fractions were characterized by pyrolysis-GC/MS with and without methylation. Methylation pyrolysis proved that the ratio between guaiacyl and syringyl units was similar in all lignin samples, but the ratio between p-coumaric and ferulic acids varied by the isolation method. Combined pyrolysis results indicated higher acylation of γ-OH groups in syringyl than in guaiacyl lignin units. The polymeric lignin structure in the alkali-soluble fraction after enzymatic hydrolysis was slightly altered in the in vitro colon fermentation, whereas lignin in the insoluble residue after enzymatic treatments remained intact. PMID:26751846

  1. FRAMEWORK FOR UNCERTAINTY ANALYSIS OF THE NAPAP (NATIONAL ACID PRECIPITATION ASSESSMENT PROGRAM) EMISSIONS INVENTORY

    EPA Science Inventory

    The report gives results of a project to develop a methodologies framework to assess the uncertainties associated with the emissions values as presented in the National Acid Precipitation Assessment Program (NAPAP) emissions inventory and to implement a prototype computer system ...

  2. SPATIAL ALLOCATION FACTOR PROCEDURES FOR THE 1980 NAPAP (NATIONAL ACID PRECIPITATION ASSESSMENT PROGRAM) EMISSIONS INVENTORY DOCUMENTATION

    EPA Science Inventory

    The report documents the development of spatial allocation factors to apportion National Acid Precipitation Assessment Program (NAPAP) area source emissions from counties to individual grid cells for input to the Regional Acid Deposition Models (RADM) and Regional Oxidant Models ...

  3. Solvent Fractionation of Lignin

    SciTech Connect

    Chatterjee, Sabornie; Saito, Tomonori

    2014-01-01

    Lignin is a highly abundant source of renewable carbon that can be considered as a valuable sustainable source of biobased materials. The major issues for the commercial production of value added high performance lignin products are lignin s physical and chemical heterogenities. To overcome these problems, a variety of procedures have been developed to produce pure lignin suitable for high performace applications such as lignin-derived carbon materials. However, most of the isolation procedures affect lignin s properties and structure. In this chapter, a short review of the effect of solvent fractionation on lignin s properties and structure is presented.

  4. Sequestration and transport of lignin monomeric precursors.

    PubMed

    Liu, Chang-Jun; Miao, Yu-Chen; Zhang, Ke-Wei

    2011-01-01

    Lignin is the second most abundant terrestrial biopolymer after cellulose. It is essential for the viability of vascular plants. Lignin precursors, the monolignols, are synthesized within the cytosol of the cell. Thereafter, these monomeric precursors are exported into the cell wall, where they are polymerized and integrated into the wall matrix. Accordingly, transport of monolignols across cell membranes is a critical step affecting deposition of lignin in the secondarily thickened cell wall. While the biosynthesis of monolignols is relatively well understood, our knowledge of sequestration and transport of these monomers is sketchy. In this article, we review different hypotheses on monolignol transport and summarize the recent progresses toward the understanding of the molecular mechanisms underlying monolignol sequestration and transport across membranes. Deciphering molecular mechanisms for lignin precursor transport will support a better biotechnological solution to manipulate plant lignification for more efficient agricultural and industrial applications of cell wall biomass. PMID:21245806

  5. Sequestration and Transport of Lignin Monomeric Precursors

    SciTech Connect

    Liu, C.J.; Miao, Y.-C.; Zhang, K.-W.

    2011-01-18

    Lignin is the second most abundant terrestrial biopolymer after cellulose. It is essential for the viability of vascular plants. Lignin precursors, the monolignols, are synthesized within the cytosol of the cell. Thereafter, these monomeric precursors are exported into the cell wall, where they are polymerized and integrated into the wall matrix. Accordingly, transport of monolignols across cell membranes is a critical step affecting deposition of lignin in the secondarily thickened cell wall. While the biosynthesis of monolignols is relatively well understood, our knowledge of sequestration and transport of these monomers is sketchy. In this article, we review different hypotheses on monolignol transport and summarize the recent progresses toward the understanding of the molecular mechanisms underlying monolignol sequestration and transport across membranes. Deciphering molecular mechanisms for lignin precursor transport will support a better biotechnological solution to manipulate plant lignification for more efficient agricultural and industrial applications of cell wall biomass.

  6. Lignin profiling in extracted xylans by size-exclusion chromatography.

    PubMed

    Hutterer, Christian; Schild, Gabriele; Kliba, Gerhard; Potthast, Antje

    2016-10-20

    Utilization of the polymeric parts of lignocellulose is expected to gain increasing importance in future biorefinery scenarios. In that respect, a particular focus is placed on hemicelluloses from different wood species gained from an industrially feasible upgrading step in the production of dissolving pulps from paper pulps. During alkaline post-extractions for hemicellulose removal, residual lignins are extracted as well. They are either covalently linked to the extracted hardwood xylans or simply co-dissolved in the alkaline lye. In order to better describe the lignin in xylan containing lyes, a method for lignin profiling was set up by hyphenating size-exclusion chromatography of xylans with UV detection which facilitates visualization of the residual lignin distribution. Simultaneous lignin quantification was achieved with lignin standards prepared from Kraft cooking liquors. The setup presented may serve as advanced characterization for novel xylan products. PMID:27474629

  7. LIGNIN ACYLATION IN GRASSES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Acylation of lignin during growth and development is a commonly found among some plant species. Grasses form unique acylated lignins involving p-coumarate (pCA). In corn rind tissue, it is exclusively attached to the gamma-carbon of lignin monomers, with a strong preference (over 90%) for attachment...

  8. Modulating lignin in plants

    DOEpatents

    Apuya, Nestor; Bobzin, Steven Craig; Okamuro, Jack; Zhang, Ke

    2013-01-29

    Materials and methods for modulating (e.g., increasing or decreasing) lignin content in plants are disclosed. For example, nucleic acids encoding lignin-modulating polypeptides are disclosed as well as methods for using such nucleic acids to generate transgenic plants having a modulated lignin content.

  9. Considerations of an air-quality standard to protect terrestrial vegetation from acidic precipitation

    SciTech Connect

    Evans, L.S.

    1981-01-01

    Studies on the effects of acidic precipitation which is here defined as wet or frozen deposition with a hydrogen ion concentration greater than 2.5 ..mu..eq 1/sup -1/, are reviewed. At the present time there is an inadequate amount of information that shows decreases in crop growth except for one field study. Most studies with plants (crops and forests) are inadequate for standard setting because they are not conducted in the field with adequate randomization of plots coupled with rigorous statistical analyses. Although visible injury to foliage has been documented in a variety of greenhouse studies, no experimental evidence demonstrates loss of field crop value or reduction in plant productivity due to visible foliar injury. Acidic precipitation can contribute nutrients to vegetation and could also influence leaching rates of nutrients from vegetation. Although these processes occur, there are no data that show changes in nutrient levels in foliage that relate to crop or natural ecosystem productivity. Experimental results show that fertilization of ferns is inhibited by current levels of acidic precipitation in the northeastern United States. However, the overall impacts of inhibited fertilization on perpetuation of the species or ecosystem productivity have not been evaluated. Simulated acidic precipitation has been shown to effect plant pathogens in greenhouse and field experiments. Simulated acidic precipitation inhibited pathogen activities under some circumstances and promoted pathogen activities under other circumstances. No conclusion can be drawn about the effects of current levels of precipitation acidity on plant pathogen-host interactions. From these data it must be concluded that research on the effects of acidic precipitation on terrestrial vegetation is too meager to draw any conclusions with regard to an air quality standard.

  10. Deciphering the Enigma of Lignification: Precursor Transport, Oxidation, and the Topochemistry of Lignin Assembly

    SciTech Connect

    Liu C. J.

    2012-03-01

    Plant lignification is a tightly regulated complex cellular process that occurs via three sequential steps: the synthesis of monolignols within the cytosol; the transport of monomeric precursors across plasma membrane; and the oxidative polymerization of monolignols to form lignin macromolecules within the cell wall. Although we have a reasonable understanding of monolignol biosynthesis, many aspects of lignin assembly remain elusive. These include the precursors transport and oxidation, and the initiation of lignin polymerization. This review describes our current knowledge of the molecular mechanisms underlying monolignol transport and oxidation, discusses the intriguing yet least-understood aspects of lignin assembly, and highlights the technologies potentially aiding in clarifying the enigma of plant lignification.

  11. DEVELOPMENT OF THE 1980 NAPAP (NATIONAL ACID PRECIPITATION ASSESSMENT PROGRAM) EMISSIONS INVENTORY

    EPA Science Inventory

    The report documents the development of the 1980 National Acid Precipitation Assessment Program (NAPAP) Emissions Inventory. The current version of the annual inventory, Version 5.0, and the related Version 5.2 Eulerian Modeling Inventory and Version 5.3 Regional Oxidant Modeling...

  12. PH BUFFERING IN FOREST SOIL ORGANIC HORIZONS: RELEVANCE TO ACID PRECIPITATION

    EPA Science Inventory

    Samples of organic surface horizons (Oi, Oe, Oa) from New York State forest soils were equilibrated with 0 to 20 cmol HNO3 Kg(-1) soil in the laboratory by a batch technique designed to simulate reactions of acid precipitation with forest floors. Each organic horizon retained a c...

  13. OCCURRENCE OF ACID PRECIPITATION ON THE WEST COAST OF THE UNITED STATES

    EPA Science Inventory

    Compilation of published and unpublished data shows acid precipitation to be more widespread in the Pacific coastal states than is generally recognized. Although information is scattered and discontinuous, precipitation is definitely acidic in the Los Angeles Basin and north-cent...

  14. Acid Precipitation Learning Materials: Science, Environmental and Social Studies, Grades 6-12.

    ERIC Educational Resources Information Center

    Hessler, Edward W.

    The major environmental problem of acid precipition is addressed through a series of activities contained in this guide for teachers of grades 6 through 12. Exercises are provided to help students learn science inquiry skills, facts, and concepts while focusing on the acid rain situation. Activities are organized by content areas. These include:…

  15. ANTHROPOGENIC EMISSIONS DATA FOR THE 1985 NAPAP (NATIONAL ACID PRECIPITATION ASSESSMENT PROGRAM) INVENTORY

    EPA Science Inventory

    The report documents the development of the anthropogenic emissions estimates to be used in the 1985 National Acid Precipitation Assessment Program (NAPAP) Emissions Inventory. Point and area source data, spanning the contiguous U.S., focus on the NAPAP high priority pollutants S...

  16. EFFECTS OF ACID PRECIPITATION ON MICROBIOLOGICAL AND CHEMICAL PARAMETERS IN SOILS: THE FLORIDA EXPERIENCE

    EPA Science Inventory

    The effects of acid precipitation on microbiological and chemical parameters in soils were investigated under field conditions. The study site consisted of three transects, each including three 75 sq. m. plots. One transect served as a control, the second one was irrigated with a...

  17. AREA SOURCE DOCUMENTATION FOR THE 1985 NATIONAL ACID PRECIPITATION ASSESSMENT PROGRAM INVENTORY

    EPA Science Inventory

    The report provides, to states and other participants and users of the 1985 National Acid Precipitation Assessment Program Emissions Inventory, a general understanding of the estimating procedures that will be used by NAPAP and EPA's Office of Air Quality Planning and Standards t...

  18. ANALYSIS OF ACID PRECIPITATION SAMPLES COLLECTED BY STATE AGENCIES--SAMPLING PERIOD JAN 1988 - DEC 1988

    EPA Science Inventory

    This report presents analytical data from the 30 acid precipitation collection sites in the State-operated Network. amples are collected weekly in plastic bag liners and shipped in 500 mL polyethylene bottles to Global Geochemistry Corporation (the central laboratory for the netw...

  19. ANALYSIS OF ACID PRECIPITATION SAMPLES COLLECTED BY STATE AGENCIES SAMPLING PERIOD JANUARY 1990 - DECEMBER 1990

    EPA Science Inventory

    This report presents analytical data from the 30 acid precipitation collection sites in the State-Operated Network. amples are collected weekly in plastic bag liners and shipped in 500 mL polyethylene bottles to Global Geochemistry Corporation (the central laboratory for the netw...

  20. ANALYSIS OF ACID PRECIPITATION SAMPLES COLLECTED BY STATE AGENCIES SAMPLING PERIOD: JANUARY 1992 - DECEMBER 1992

    EPA Science Inventory

    This report presents analytical data from 30 acid precipitation collection sites in the State-Operated Network. amples are collected weekly in plastic bag bucket liners and shipped in 500 mL polyethylene bottled to Global Geochemistry Corporation, the central laboratory for the n...

  1. ANALYSIS OF ACID PRECIPITATION SAMPLES COLLECTED BY STATE AGENCIES: JANUARY 1987 - DECEMBER 1987

    EPA Science Inventory

    The report presents the analytical data from the 31 acid precipitation collection sites in the State Operated Network. Samples are collected weekly in plastic bag liners and shipped in 500 mL polyethylene bottles to Global Geochemistry Corp. (the central laboratory for the networ...

  2. Conformations of Low-Molecular-Weight Lignin Polymers in Water.

    PubMed

    Petridis, Loukas; Smith, Jeremy C

    2016-02-01

    Low-molecular-weight lignin binds to cellulose during the thermochemical pretreatment of biomass for biofuel production, which prevents the efficient hydrolysis of the cellulose to sugars. The binding properties of lignin are influenced strongly by the conformations it adopts. Here, we use molecular dynamics simulations in aqueous solution to investigate the dependence of the shape of lignin polymers on chain length and temperature. Lignin is found to adopt collapsed conformations in water at 300 and 500 K. However, at 300 K, a discontinuous transition is found in the shape of the polymer as a function of the chain length. Below a critical degree of polymerization, Nc =15, the polymer adopts less spherical conformations than above Nc. The transition disappears at high temperatures (500 K) at which only spherical shapes are adopted. An implication relevant to cellulosic biofuel production is that lignin will self-aggregate even at high pretreatment temperatures. PMID:26763657

  3. Coexistence but Independent Biosynthesis of Catechyl and Guaiacyl/Syringyl Lignin Polymers in Seed Coats[W][OPEN

    PubMed Central

    Tobimatsu, Yuki; Chen, Fang; Nakashima, Jin; Escamilla-Treviño, Luis L.; Jackson, Lisa; Dixon, Richard A.; Ralph, John

    2013-01-01

    Lignins are phenylpropanoid polymers, derived from monolignols, commonly found in terrestrial plant secondary cell walls. We recently reported evidence of an unanticipated catechyl lignin homopolymer (C lignin) derived solely from caffeyl alcohol in the seed coats of several monocot and dicot plants. We previously identified plant seeds that possessed either C lignin or traditional guaiacyl/syringyl (G/S) lignins, but not both. Here, we identified several dicot plants (Euphorbiaceae and Cleomaceae) that produce C lignin together with traditional G/S lignins in their seed coats. Solution-state NMR analyses, along with an in vitro lignin polymerization study, determined that there is, however, no copolymerization detectable (i.e., that the synthesis and polymerization of caffeyl alcohol and conventional monolignols in vivo is spatially and/or temporally separated). In particular, the deposition of G and C lignins in Cleome hassleriana seed coats is developmentally regulated during seed maturation; C lignin appears successively after G lignin within the same testa layers, concurrently with apparent loss of the functionality of O-methyltransferases, which are key enzymes for the conversion of C to G lignin precursors. This study exemplifies the flexible biosynthesis of different types of lignin polymers in plants dictated by substantial, but poorly understood, control of monomer supply by the cells. PMID:23903315

  4. Acid Precipitation

    ERIC Educational Resources Information Center

    Likens, Gene E.

    1976-01-01

    Discusses the fact that the acidity of rain and snow falling on parts of the U.S. and Europe has been rising. The reasons are still not entirely clear and the consequences have yet to be well evaluated. (MLH)

  5. Pathways for Biomass-Derived Lignin to Hydrocarbon Fuels

    SciTech Connect

    Laskar, Dhrubojyoti; Yang, Bin; Wang, Huamin; Lee, Guo-Shuh J.

    2013-09-01

    Production of hydrocarbon fuel from biomass-derived lignin sources with current version of biorefinery infrastructure would significantly improve the total carbon use in biomass and make biomass conversion more economically viable. Thus, developing specialty and commodity products from biomass derived-lignin has been an important industrial and scientific endeavor for several decades. However, deconstruction of lignin’s complex polymeric framework into low molecular weight reactive moieties amenable for deoxygenation and subsequent processing into hydrocarbons has been proven challenging. This review offers a comprehensive outlook on the existing body of work that has been devoted to catalytic processing of lignin derivatives into hydrocarbon fuels, focusing on: (1) The intrinsic complexity and characteristic structural features of biomass-derived lignin; (2) Existing processing technologies for the isolation and depolymerization of bulk lignin (including detailed mechanistic considerations); (3) Approaches aimed at significantly improving the yields of depolymerized lignin species amenable to catalytic upgrading, and; (4) Catalytic upgrading, using aqueous phase processes for transforming depolymerized lignin to hydrocarbon derivatives. Technical barriers and challenges to the valorization of lignin are highlighted throughout. The central goal of this review is to present an array of strategies that have been reported to obtain lignin, deconstruct it to reactive intermediates, and reduce its substantial oxygen content to yield hydrocarbon liquids. In this regard, reaction networks with reference to studies of lignin model compounds are exclusively surveyed. Special attention is paid to catalytic hydrodeoxygenation, hydrogenolyis and hydrogenation. Finally, this review addresses important features of lignin that are vital to economic success of hydrocarbon production.

  6. Lignin-rich Enzyme Lignin (LREL), a Cellulase-treated Lignin-Carbohydrate Derived from Plants, Activates Myeloid Dendritic Cells via Toll-like Receptor 4 (TLR4)

    PubMed Central

    Tsuji, Ryohei; Koizumi, Hideki; Aoki, Dan; Watanabe, Yuta; Sugihara, Yoshihiko; Matsushita, Yasuyuki; Fukushima, Kazuhiko; Fujiwara, Daisuke

    2015-01-01

    Lignin-carbohydrates, one of the major cell wall components, are believed to be the structures that form chemical linkage between lignin and cell wall polysaccharides. Due to the molecular complexity of lignin-containing substances, their isolation and the assignment of their biological activities have so far remained a difficult task. Here, we extracted two lignin-containing carbohydrates, lignin-rich enzyme lignin (LREL) and pure enzyme lignin (PEL), from barley husk and demonstrated that they act as immune stimulators of dendritic cells (DCs), which are particularly important in linking innate and adaptive immunity. Thioacidolysis, acid hydrolysis, and mild alkali hydrolysis of both LREL and PEL revealed that their immunostimulatory activities depended on the lignin structure and/or content, neutral sugar content (especially the characteristic distribution of galactose and mannose), and presence of an ester bond. Furthermore, we showed that the immunostimulatory potency of the lignin-carbohydrate depended on its molecular weight and degree of polymerization. We also demonstrated that the LREL-induced activation of DCs was mediated via TLR4. Thus, LREL-induced increases in the expression levels of several cell surface marker proteins, production of inflammatory cytokines IL-12p40 and TNF-α, and activation and nuclear translocation of transcription factors, as was observed in the WT DCs, were completely abrogated in DCs derived from the TLR4−/− mice but not in DCs derived from the TLR2−/−, TLR7−/−, and TLR9−/− mice. We further demonstrated that LRELs isolated from other plant tissues also activated DCs. These immunostimulatory activities of lignin-carbohydrates, extracted from edible plant tissues, could have potential relevance in anti-infectious immunity and vaccine adjuvants. PMID:25548274

  7. Molecular architecture requirements for polymer-grafted lignin superplasticizers.

    PubMed

    Gupta, Chetali; Sverdlove, Madeline J; Washburn, Newell R

    2015-04-01

    Superplasticizers are a class of anionic polymer dispersants used to inhibit aggregation in hydraulic cement, lowering the yield stress of cement pastes to improve workability and reduce water requirements. The plant-derived biopolymer lignin is commonly used as a low-cost/low-performance plasticizer, but attempts to improve its effects on cement rheology through copolymerization with synthetic monomers have not led to significant improvements. Here we demonstrate that kraft lignin can form the basis for high-performance superplasticizers in hydraulic cement, but the molecular architecture must be based on a lignin core with a synthetic-polymer corona that can be produced via controlled radical polymerization. Using slump tests of ordinary Portland cement pastes, we show that polyacrylamide-grafted lignin prepared via reversible addition-fragmentation chain transfer polymerization can reduce the yield stress of cement paste to similar levels as a leading commercial polycarboxylate ether superplasticizer at concentrations ten-fold lower, although the lignin material produced via controlled radical polymerization does not appear to reduce the dynamic viscosity of cement paste as effectively as the polycarboxylate superplasticizer, despite having a similar affinity for the individual mineral components of ordinary Portland cement. In contrast, polyacrylamide copolymerized with a methacrylated kraft lignin via conventional free radical polymerization having a similar overall composition did not reduce the yield stress or the viscosity of cement pastes. While further work is required to elucidate the mechanism of this effect, these results indicate that controlling the architecture of polymer-grafted lignin can significantly enhance its performance as a superplasticizer for cement. PMID:25693832

  8. Acid precipitation. (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect

    Not Available

    1993-07-01

    The bibliography contains citations concerning the causes, and ecological and economic consequences of acid precipitation and deposition. Emissions of sulfur and nitrogen compounds, loading rates at specific study sites, the role of buffering materials on the acidification of lakes and streams, and the effects on aquatic life are considered. The effects on soil chemistry and vegetation are also discussed. (Contains 250 citations and includes a subject term index and title list.)

  9. Composition and hygroscopicity of aerosol particles at Mt. Lu in South China: Implications for acid precipitation

    NASA Astrophysics Data System (ADS)

    Li, Weijun; Chi, Jianwei; Shi, Zongbo; Wang, Xinfeng; Chen, Bin; Wang, Yan; Li, Tao; Chen, Jianmin; Zhang, Daizhou; Wang, Zifa; Shi, Chune; Liu, Liangke; Wang, Wenxing

    2014-09-01

    Physicochemical properties of aerosol particles were studied at Mt. Lu, an elevated site (115°59‧E, 29°35‧N, 1165 m) within the acid precipitation area. Northeast winds transport copious amounts of air pollutants and water vapor from the Yangtze River Delta into this acid precipitation area. NH4+ and SO42- are the dominant ions in PM2.5 and determine aerosol acidity. Individual particle analysis shows abundant S-rich and metals (i.e. Fe-, Zn-, Mn-, and Pb-rich) particles. Unlike aerosol particles in North China and urban areas, there are little soot and mineral particles at Mt. Lu. Lack of mineral particles contributed to the higher acidity in precipitation in the research area. Nano-sized spherical metal particles were observed to be embedded in 37% of S-rich particles. These metal particles were likely originated from heavy industries and fired-power plants. Hygroscopic experiments show that most particles start to deliquesce at 73-76% but organic coating lowers the particle deliquescence relative humidity (DRH) to 63-73%. The DRHs of these aerosol particles are clearly smaller than that of pure ammonium sulfate particles which is 80%. Since RH in ambient air was relatively high, ranging from 65% to 85% during our study period, most particles at our sampling site were in liquid phase. Our results suggest that liquid phase reactions in aerosol particles may contribute to SO2 to sulfuric acid conversion in the acid precipitation area.

  10. Exploring bacterial lignin degradation.

    PubMed

    Brown, Margaret E; Chang, Michelle C Y

    2014-04-01

    Plant biomass represents a renewable carbon feedstock that could potentially be used to replace a significant level of petroleum-derived chemicals. One major challenge in its utilization is that the majority of this carbon is trapped in the recalcitrant structural polymers of the plant cell wall. Deconstruction of lignin is a key step in the processing of biomass to useful monomers but remains challenging. Microbial systems can provide molecular information on lignin depolymerization as they have evolved to break lignin down using metalloenzyme-dependent radical pathways. Both fungi and bacteria have been observed to metabolize lignin; however, their differential reactivity with this substrate indicates that they may utilize different chemical strategies for its breakdown. This review will discuss recent advances in studying bacterial lignin degradation as an approach to exploring greater diversity in the environment. PMID:24780273

  11. National Acid Precipitation Assessment Program: Acidic deposition: An inventory of non-Federal research, monitoring, and assessment information

    SciTech Connect

    Herrick, C.N.

    1990-01-01

    The Acid Precipitation Act of 1990 (Title VII of the Energy Security Act of 1980, P.L. 96-294) established the Interagency Task Force on Acid Precipitation to develop and implement the National Acid Precipitation Assessment Program (NAPAP). The information included in the document was provided to NAPAP's Task Group Leaders and State-of-Science and State-of-Technology authors in July 1989. The early release was intended to assure that the authors would be aware of the information at an early phase in the assessment production process.

  12. A mechanism for localized lignin deposition in the endodermis.

    PubMed

    Lee, Yuree; Rubio, Maria C; Alassimone, Julien; Geldner, Niko

    2013-04-11

    The precise localization of extracellular matrix and cell wall components is of critical importance for multicellular organisms. Lignin is a major cell wall modification that often forms intricate subcellular patterns that are central to cellular function. Yet the mechanisms of lignin polymerization and the subcellular precision of its formation remain enigmatic. Here, we show that the Casparian strip, a lignin-based, paracellular diffusion barrier in plants, forms as a precise, median ring by the concerted action of a specific, localized NADPH oxidase, brought into proximity of localized peroxidases through the action of Casparian strip domain proteins (CASPs). Our findings in Arabidopsis provide a simple mechanistic model of how plant cells regulate lignin formation with subcellular precision. We speculate that scaffolding of NADPH oxidases to the downstream targets of the reactive oxygen species (ROS) that they produce might be a widespread mechanism to ensure specificity and subcellular precision of ROS action within the extracellular matrix. PMID:23541512

  13. Optimizing Noncovalent Interactions Between Lignin and Synthetic Polymers to Develop Effective Compatibilizers

    SciTech Connect

    Henry, Nathan; Harper, David; Dadmun, Mark D

    2012-01-01

    Experiments are designed and completed to identify an effective polymeric compatibilizer for lignin polystyrene blends. Copolymers of styrene and vinylphenol are chosen as the structure of the compatibilizer as the VPh unit can readily form intermolecular hydrogen bonds with the lignin molecule. Electron microscopy, thermal analysis, and neutron refl ectivity results demonstrate that among these compatibilizers, a copolymer of styrene and VPh with 20% 30% VPh most readily forms intermolecular interactions with the lignin molecule and results in the most well-dispersed blends with lignin. This behavior is explained by invoking the competition of intra- and intermolecular hydrogen bonding and functional group accessibility in forming intermolecular interactions.

  14. Occurrence of acid precipitation on the West Coast of the United States

    SciTech Connect

    Powers, C.F.; Rambo, D.L.

    1981-01-01

    Compilation of published and unpublished data shows acid precipitation to be more widespread in the Pacific coastal states than is generally recognized. Although information is scattered and discontinuous, precipitation is definitely acidic in the Los Angeles Basin and north-central California and in the Puget Sound region in Washington. Acid-rain occurrences were observed in western and eastern Oregon, but data are inadequate for regional generalization. New stations currently being established in Washington and Oregon, largely in response to the recently renewed activity of Mount St. Helens, will greatly facilitate assessment of precipitation acidity in the Northwest.

  15. UV-absorbent lignin-based multi-arm star thermoplastic elastomers.

    PubMed

    Yu, Juan; Wang, Jifu; Wang, Chunpeng; Liu, Yupeng; Xu, Yuzhi; Tang, Chuanbing; Chu, Fuxiang

    2015-02-01

    Lignin-grafted copolymers, namely lignin-graft-poly(methyl methacrylate-co-butyl acrylate) (lignin-g-P(MMA-co-BA)), are synthesized via "grafting from" atom transfer radical polymerization (ATRP) with the aid of lignin-based macroinitiators. By manipulating the monomer feed ratios of MMA/BA, grafted copolymers with tunable glass transition temperatures (-10-40 °C) are obtained. These copolymers are evaluated as sustainable thermoplastic elastomers (TPEs). The results suggest that the mechanical properties of these TPEs lignin-g-P(MMA-co-BA) copolymers are improved significantly by comparing with those of linear P(MMA-co-BA) copolymer counterparts, and the elastic strain recovery is nearly 70%. Lignin-g-P(MMA-co-BA) copolymers exhibit high absorption in the range of the UV spectrum, which might allow for applications in UV-blocking coatings. PMID:25545630

  16. Tunable Pickering emulsions with polymer-grafted lignin nanoparticles (PGLNs).

    PubMed

    Silmore, Kevin S; Gupta, Chetali; Washburn, Newell R

    2016-03-15

    activities, and polymer-nanoparticle interactions are critical for optimizing interfacial activities. Controlled radical polymerization is a powerful tool for polymer grafting that can leverage the intrinsic interfacial functions of lignin for the formation of Pickering emulsions. PMID:26707776

  17. Natural acidity of waters in podzolized soils and potential impacts from acid precipitation

    SciTech Connect

    Stednick, J.D.; Johnson, D.W.

    1982-01-01

    Nutrient movements through sites in southeast Alaska and Washington were documented to determine net changes in chemical composition of precipitation water as it passed through a forest soil and became stream-flow. These sites were not subject to acid precipitation (rainfall pH 5.8 to 7.2), yet soil water was acidified to 4.2 by natural organic acid-forming processes in the podzol soils. Organic acids precipitated in the subsoils, allowing a pH increase. Streamwater pH ranged from 6.5 to 7.2 indicating a natural buffering capacity that may exceed any additional acid input from acid rain. Precipitation composition was dominated by calcium, magnesium, sodium, and chloride due to the proximity of the ocean at the southeast Alaska site. Anionic constituents of the precipitation were dominated by bicarbonate at the Washington site. Soil podzolization processes concurrently increased solution color and iron concentrations in the litter and surface horizons leachates. The anion flux through the soil profile was dominated by chloride and sulfate at the southeast Alaska site, whereas at the Washington site anion flux appeared to be dominated by organic acids. Electroneutrality calculations indicated a cation deficit for the southeast Alaska site.

  18. Natural acidity of waters in podzolized soils and potential impacts from acid precipitation

    SciTech Connect

    Stednick, J.D.; Johnson, D.W.

    1982-01-01

    Nutrient movements through sites in southeast Alaska and Washington were documented to determine net changes in chemical composition of precipitation water as it passed through a forest soil and became stream flow. These sites were not subject to acid precipitation (rainfall pH 5.8 to 7.2), yet soil water was acidified to 4.2 by natural organic acid forming processes in the podzol soils. Organic acids precipitated in the subsoils, allowing a pH increase. Stream water pH ranged from 6.5 to 7.2 indicating a natural buffering capacity that may exceed any additional acid input from acid rain. Precipitation composition was dominated by magnesium, sodium, and chloride due to the proximity of the ocean at the southeast Alaska site. Anionic constituents of the precipitation were dominated by bicarbonate at the Washington site. Soil podzolization processes concurrently increased solution color and iron concentrations in the litter and surface horizons leachates. The anion flux through the soil profile was dominated by chloride and sulfate at the southwast Alaska site, whereas at the Washington site anion flux appeared to be dominated by organic acids. Electroneutrality calculations indicated a cation deficit for the southeast Alaska site. 10 references, 2 tables.

  19. Effect of atmospheric sulfur pollutants derived from acid precipitation on the benthic dynamics of lakes

    SciTech Connect

    Mitchell, M.J.

    1982-11-01

    Sulfuric acid is a major contributor to acid precipitation in the United States. The relationship of acid precipitation to the sulfur dynamics of three lakes in New York was studied. For South Lake, which has probably been acidified, the sulfur profile in the sediment corresponded to historical changes in anthropogenic sulfur inputs. In all three study lakes, the organic sulfur constituents, which generally have been ignored in limnological investigations, played a major role in sulfur dynamics. The transformations and fluxes of inorganic and organic sulfur differed among the lakes and reflected characteristic abiotic and biotic properties, including productivity parameters. The community structure and secondary production of the invertebrate benthos were ascertained and, for South Lake, were similar to other acidified lakes. The importance of benthic insects on sulfur dynamics was demonstrated. Further studies on sulfur in lakes will enhance the understanding of the role of these anthropogenic inputs on lake systems and permit a more accurate appraisal of the present and future impacts of acidic deposition on water quality. 10 references.

  20. Effectiveness of coagulation and acid precipitation processes for the pre-treatment of diluted black liquor.

    PubMed

    Garg, Anurag; Mishra, I M; Chand, S

    2010-08-15

    The effectiveness of coagulation (using aluminium-based chemicals and ferrous sulfate) and acid precipitation (using H(2)SO(4)) processes for the pre-treatment of diluted black liquor obtained from a pulp and paper mill is reported. Commercial alum was found to be the most economical among all the aluminium and ferrous salts used as a coagulant. A maximum removal of chemical oxygen demand (COD) (ca. 63%) and colour reduction (ca. 90%) from the wastewater (COD = 7000 mg l(-1)) at pH 5.0 was obtained with alum. During the acid precipitation process, at pH < 5.0, significant COD reductions (up to 64%) were observed. Solid residue obtained from the alum treatment at a temperature of 95 degrees C showed much better (3 times) settling rate than that for the residue obtained after treatment with the same coagulant at a temperature of 25 degrees C. The settling curves had three parts, namely, hindered, transition and compression zones. Tory plots were used to determine the critical height of suspension-supernatant interface that is used in the design of a clarifier-thickener unit. High heating values and large biomass fraction of the solid residues can encourage the fuel users to use this waste derived sludge as a potential renewable energy source. PMID:20430523

  1. Chromium adsorption by lignin

    SciTech Connect

    Lalvani, S.B.; Huebner, A.; Wiltowski, T.S.

    2000-01-01

    Hexavalent chromium is a known carcinogen, and its maximum contamination level in drinking water is determined by the US Environmental Protection Agency (EPA). Chromium in the wastewaters from plating and metal finishing, tanning, and photographic industries poses environmental problems. A commercially available lignin was used for the removal of hexavalent as well as trivalent chromium from aqueous solution. It is known that hexavalent chromium is present as an anionic species in the solution. It was found that lignin can remove up to 63% hexavalent and 100% trivalent chromium from aqueous solutions. The removal of chromium ions was also investigated using a commercially available activated carbon. This absorbent facilitated very little hexavalent and almost complete trivalent chromium removal. Adsorption isotherms and kinetics data on the metal removal by lignin and activated carbon are presented and discussed.

  2. Extracting lignins from mill wastes

    NASA Technical Reports Server (NTRS)

    Humphrey, M. F.

    1977-01-01

    Addition of quaternary ammonium compound and activated charcoal to pulp and mill wastes precipitates lignins in sludge mixture. Methanol dissolves lignins for separation from resulting slurry. Mineral acid reprecipitates lignins in filtered solution. Quaternary ammonium compound, activated charcoal, as well as water may be recovered and recycled from this process.

  3. Starch-Lignin Baked Foams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch-kraft lignin foams were prepared by a baking process. Replacing up to 20% of the starch with lignin has no effect on foam density or overall morphology. At 10% replacement, lignin marginally increases water resistance and modulus of elasticity but decreases strain at maximum stress. At 20% re...

  4. Fluorescence analyzer for lignin

    DOEpatents

    Berthold, John W.; Malito, Michael L.; Jeffers, Larry

    1993-01-01

    A method and apparatus for measuring lignin concentration in a sample of wood pulp or black liquor comprises a light emitting arrangement for emitting an excitation light through optical fiber bundles into a probe which has an undiluted sensing end facing the sample. The excitation light causes the lignin concentration to produce fluorescent emission light which is then conveyed through the probe to analyzing equipment which measures the intensity of the emission light. Measures a This invention was made with Government support under Contract Number DOE: DE-FC05-90CE40905 awarded by the Department of Energy (DOE). The Government has certain rights in this invention.

  5. Effects of ozone, sulfur dioxide and acidic precipitation on formation of ectomycorrhizae by forest tree seedlings

    SciTech Connect

    Keane, K.D.; Manning, W.J. )

    1987-01-01

    Gaseous air pollutants and acidic precipitation impact upon forest ecosystems. Forest declines in central Europe and, more recently, in the northeastern United States have been largely attributed to these air pollutants. The possible direct effects of these air pollutants, such as foliar injury and growth reductions, on forests have been extensively investigated. Potential secondary effects of air pollutants, on tree root processes such as ectomycorrhizae, have received much less attention. These secondary effects are addressed in this paper. Ectomycorrhizae are symbiotic fungal-root associations in which fungal hyphae penetrate the cortex of plant roots intercellularly to form a structure called Hartig net. Mycorrhizal fungi typically become associated with the fine feeder roots of their hosts. The ectomyocorrhizae, once associated, results in distinct morphological changes in these roots. Ectomycorrhizae are known to associate with most tree species.

  6. Effects of acid precipitation on reproduction in alpine plant species. [Erythronium grandiflorum; Aquilegia caerulea

    SciTech Connect

    McKenna, M.A.; Hille-Salgueiro, M.; Musselman, R.C. Dept. of Agriculture, Fort Collins, CO )

    1990-01-01

    A series of experiments were designed to determine the impact of acid rain on plant reproductive processes, a critical component of a species life history. Research was carried out in herbaceous alpine communities at the USDA (United States Department of Agriculture) Forest Service Glacier Lakes Ecosystem Experiments Site in the Snowy Mts. of Wyoming. A range of species were surveyed to monitor the sensitivity of pollen to acidification during germination and growth, and all species demonstrated reduced in vitro pollen germination in acidified media. Field pollinations were carried out in Erythronium grandiflorum and Aquilegia caerulea to determine the reproductive success of plants exposed to simulated ambient precipitation (pH 5.6) or simulated acid precipitation (pH 3.6) prior to pollination. In Erythronium, no differences were observed in seed set and seed weight of fruits resulting from the two pollination treatments. In Aquilegia, fruits resulting from the acid spray treatment produced fewer seeds and lighter seeds.

  7. Evaluation of simulated acid precipitation effects on forest microcosms. Final report

    SciTech Connect

    Kelly, J.M.; Strickland, R.C.; Weatherford, F.P.; Noggle, J.C.

    1984-04-01

    Microcosms were treated for a 30-month period with simulated precipitation acidified to four pH levels (5.7, 4.5, 4.0, and 3.5) to evaluate the impact of acid precipitation on foliar leaching, plant nutrient content, soil leaching, soil nutrient content, and litter decomposition. Direct effects of acid precipitation on diameter growth, bud break, leaf senescence, chlorophyll content, stomatal size, stomatal density, photosynthesis, respiration, transpiration, and cuticle erosion were evaluated on tulip poplar, white oak, and Virginia pine seedlings growing as mixed stands in the microcosms. None of the plant physiological or morphological parameters evaluated responded in a statistically significant manner as a result of treatment. A significant treatment canopy interaction was observed in the form of a 60 percent increase in calcium input in throughfall in response to the pH 3.5 treatment. Foliar nutrient content did not change in response to treatment nor did field measurements of decomposer activity. Soil analysis indicated a significantly lower concentration of exchangeable calcium and magnesium in the top 3.5 cm of the mineral soil in association with the pH 3.5 treatment. Soil leachate concentrations exhibited significant increases at both the 25 and 50 cm depths. However, at the 100 cm depth no significant response in concentration or elemental loss from the system was observed. Laboratory respiration measurements indicated a small, but statistically significant reduction in decomposer activity in the lower litter (02) horizon. This reduction was masked in the field measurements of decomposer activity due to the relatively small contribution of the 02 to total soil respiration. 38 references, 12 figures, 18 tables.

  8. Acidic precipitation-induced chemical changes in subalpine fir forest organic soil layers

    SciTech Connect

    Hanson, D.W.

    1980-01-01

    The effects of acid precipitation and heavy metal deposition on the surface organic layer of conifer forest soils of New England and Canada were studied. Trends in concentrations of elements across the regional precipitation pH gradient were analyzed. Leaching of Mn, and Ca from subalpine fir forest soil litter increased as precipitation acidity increased. The order of relative susceptibility to increased leaching due to increased precipitation acidity is Mn > Ca > Mg greater than or equal to K greater than or equal to Zn. Sodium and Cd possibly show leaching patterns similar to those of Mg, K, and Zn. Iron and Pb concentrations increased as precipitation acidity increased. The Fe and Pb concentration gradients are partially caused by relative enrichment of Fe and Pb in litter as more mobile cations and compounds are leached. Relative enrichment was greatest at sites receiving precipitation of greater acidity. A large part of the Pb concentration gradient in litter is due to an atmospheric Pb deposition gradient which parallels the regional precipitation-pH gradient. The order of relative accumulation is Pb > Fe. Lead concentrations were highest in soil L and F layers, indicating that Pb accumulation is a recent, continuing phenomenon. Soil litter showed a pH gradient across the sampling transect. Litter generally increased in acidity as precipitation acidity increased. Increased soil litter acidity and increased cation leaching are related; both are caused by acidic precipitation. Cluster analysis of soil litter chemistry data ordered the mountain sites, with one exception, according to their position along the regional precipitation-pH gradient. This implies that precipitation-pH, and associated heavy metal deposition, control soil litter chemistry in subalpine fir forests. 113 references. (MDF)

  9. Microbial degradation of lignin-derived compounds under anaerobic conditions

    SciTech Connect

    Colberg, P.J.

    1983-01-01

    Lignin is the second most abundant form of organic carbon in the biosphere. Recent laboratory studies indicate that a large fraction of polymeric lignin is incompletely degraded by aerobic lignolytic microorganisms and is subsequently released as lignin fragments of reduced molecular size. If such lignin-derived compounds become available in the anaerobic environment, they may serve as potential sources of organic carbon for organisms which release methane precursors. The methanogenic bacteria, in turn, serve as terminal members of the anaerobic food chain, and thus, limit the accumulation of organic carbon in anaerobic sinks. This thesis presents evidence to suggest that lignin-derived compounds which have molecular sizes greater than those of single-ring aromatic compounds (MW > 200) are anaerobically biodegradable to methane. This research involved development of selective enrichment cultures capable of utilizing oligolignols as sole carbon sources. Radiolabeled water-soluble catabolites, released during aerobic lignin degradation by the white rot fungus Phanerochaete chrysosporium, were subjected to anaerobic degradation. The second phase of work involved capillary gas chromatographic analyses of enrichment cultures fed a /sup 14/C-labeled, lignin-derived substrate of average molecular weight 600. 2-Bromoethanesulfonic acid was used to inhibit methane formation and enhance buildup of metabolic intermediates, resulting in the accumulation of volatile fatty acids, phenylacetate, benzoate, catechol, 3-phenyl-propionate, vanillin, syringic acid, vanillic acid, ferulic acid, and caffeic acid. A conceptual model for the anaerobic degradation of two- and three-ring lignin fragments is proposed which overlaps both the ferulate and benzoate degradation pathways at the level of single-ring aromatic compounds.

  10. Lignin blockers and uses thereof

    DOEpatents

    Yang, Bin; Wyman, Charles E.

    2011-01-25

    Disclosed is a method for converting cellulose in a lignocellulosic biomass. The method provides for a lignin-blocking polypeptide and/or protein treatment of high lignin solids. The treatment enhances cellulase availability in cellulose conversion and allows for the determination of optimized pretreatment conditions. Additionally, ethanol yields from a Simultaneous Saccharification and Fermentation process are improved 5-25% by treatment with a lignin-blocking polypeptide and/or protein. Thus, a more efficient and economical method of processing lignin containing biomass materials utilizes a polypeptide/protein treatment step that effectively blocks lignin binding of cellulase.

  11. Biosynthsis of Lignin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to understand the effects of up- and down-regulating genes on the lignin biosynthetic pathway, the intracacies of the pathway should be known. Many of the genes are long-known, although the actual substrates of some have been clarified in planta. Others are surprisingly new. All of the majo...

  12. Self-similar multiscale structure of lignin revealed by neutron scattering and molecular dynamics simulation

    SciTech Connect

    Petridis, Loukas; Pingali, Sai Venkatesh; Urban, Volker; Heller, William T; O'Neill, Hugh Michael; Foston, Marcus B; Ragauskas, Arthur J; Smith, Jeremy C

    2011-01-01

    Lignin, a major polymeric component of plant cell walls, forms aggregates in vivo and poses a barrier to cellulosic ethanol production. Here, neutron scattering experiments and molecular dynamics simulations reveal that lignin aggregates are characterized by a surface fractal dimension that is invariant under change of scale from 1 1000 A. The simulations also reveal extensive water penetration of the aggregates and heterogeneous chain dynamics corresponding to a rigid core with a fluid surface.

  13. A versatile click-compatible monolignol probe to study lignin deposition in plant cell walls.

    PubMed

    Pandey, Jyotsna L; Wang, Bo; Diehl, Brett G; Richard, Tom L; Chen, Gong; Anderson, Charles T

    2015-01-01

    Lignin plays important structural and functional roles in plants by forming a hydrophobic matrix in secondary cell walls that enhances mechanical strength and resists microbial decay. While the importance of the lignin matrix is well documented and the biosynthetic pathways for monolignols are known, the process by which lignin precursors or monolignols are transported and polymerized to form this matrix remains a subject of considerable debate. In this study, we have synthesized and tested an analog of coniferyl alcohol that has been modified to contain an ethynyl group at the C-3 position. This modification enables fluorescent tagging and imaging of this molecule after its incorporation into plant tissue by click chemistry-assisted covalent labeling with a fluorescent azide dye, and confers a distinct Raman signature that could be used for Raman imaging. We found that this monolignol analog is incorporated into in vitro-polymerized dehydrogenation polymer (DHP) lignin and into root epidermal cell walls of 4-day-old Arabidopsis seedlings. Incorporation of the analog in stem sections of 6-week-old Arabidopsis thaliana plants and labeling with an Alexa-594 azide dye revealed the precise locations of new lignin polymerization. Results from this study indicate that this molecule can provide high-resolution localization of lignification during plant cell wall maturation and lignin matrix assembly. PMID:25884205

  14. A Versatile Click-Compatible Monolignol Probe to Study Lignin Deposition in Plant Cell Walls

    PubMed Central

    Pandey, Jyotsna L.; Wang, Bo; Diehl, Brett G.; Richard, Tom L.; Chen, Gong; Anderson, Charles T.

    2015-01-01

    Lignin plays important structural and functional roles in plants by forming a hydrophobic matrix in secondary cell walls that enhances mechanical strength and resists microbial decay. While the importance of the lignin matrix is well documented and the biosynthetic pathways for monolignols are known, the process by which lignin precursors or monolignols are transported and polymerized to form this matrix remains a subject of considerable debate. In this study, we have synthesized and tested an analog of coniferyl alcohol that has been modified to contain an ethynyl group at the C-3 position. This modification enables fluorescent tagging and imaging of this molecule after its incorporation into plant tissue by click chemistry-assisted covalent labeling with a fluorescent azide dye, and confers a distinct Raman signature that could be used for Raman imaging. We found that this monolignol analog is incorporated into in vitro-polymerized dehydrogenation polymer (DHP) lignin and into root epidermal cell walls of 4-day-old Arabidopsis seedlings. Incorporation of the analog in stem sections of 6-week-old Arabidopsis thaliana plants and labeling with an Alexa-594 azide dye revealed the precise locations of new lignin polymerization. Results from this study indicate that this molecule can provide high-resolution localization of lignification during plant cell wall maturation and lignin matrix assembly. PMID:25884205

  15. Geological and hydrochemical sensitivity of the eastern United States to acid precipitation

    SciTech Connect

    Hendrey, G.R.; Galloway, J.N.; Norton, S.A.; Schofield, C.L.; Shaffer, P.W.; Burns, D.A.

    1980-03-01

    A new analysis of bedrock geology maps of the eastern US constitutes a simple model for predicting areas which might be impacted by acid precipitation and it allows much greater resolution for detecting sensitivity than has previously been available for the region. Map accuracy has been verified by examining current alkalinities and pH's of waters in several test states, including Maine, New Hampshire, New York, Virginia and North Carolina. In regions predicted to be highly sensitive, alkalinities in upstream sites were generally low. Many areas of the eastern US are pinpointed in which some of the surface waters, especially upstream reaches, may be sensitive to acidification. Pre-1970 data were compared to post-1975 data, revealing marked declines in both alkalinity and pH of sensitive waters of two states tested, North Carolina, where pH and alkalinity have decreased in 80% of 38 streams and New Hampshire, where pH in 90% of 49 streams and lakes has decreased since 1949. These sites are predicted to be sensitive by the geological map on the basis of their earlier alkalinity values. The map is to be improved by the addition of a soils component.

  16. National Acid Precipitation Assessment Program Report to Congress: An Integrated Assessment

    SciTech Connect

    Uhart, M.; et al,

    2005-08-01

    Under Title IX of the 1990 Clean Air Act Amendments, Congress reauthorized the National Acid Precipitation Assessment Program (NAPAP) to continue coordinating acid rain research and monitoring, as it had done during the previous decade, and to provide Congress with periodic reports. In particular, Congress asked NAPAP to assess all available data and information to answer two questions: (1) What are the costs, benefits, and effectiveness of Title IV? This question addresses the costs and economic impacts of complying with the Acid Rain Program as well as benefit analyses associated with the various human health and welfare effects, including reduced visibility, damages to materials and cultural resources, and effects on ecosystems. (2) What reductions in deposition rates are needed to prevent adverse ecological effects? This complex questions addresses ecological systems and the deposition levels at which they experience harmful effects. The results of the assessment of the effects of Title IV and of the relationship between acid deposition rates and ecological effects were to be reported to Congress quadrennially, beginning with the 1996 report to Congress. The objective of this Report is to address the two main questions posed by Congress and fully communicate the results of the assessment to decision-makers. Given the primary audience, most of this report is not written as a technical document, although information supporting the conclusions is provided along with references.

  17. Weathering processes and pickeringite formation in a sulfidic schist: a consideration in acid precipitation neutralization studies

    SciTech Connect

    Parnell, R.A. Jr.

    1983-01-01

    Extremely low abrasion pH values (2.8-3.3) characterize the weathering products of the Partridge Formation, a Middle-Ordovician metamorphosed, black, sulfidic shale. The local occurrence is observed of two sulfates that are rare in the Northeast: pickeringite and jarosite. X-ray diffraction studies of the weathering residues and the sulfate efflorescences have also identified dioctahedral and trioctahedral illite, kaolinite, vermiculite, and an 11-12 Angstrom phase, thought to be a type of randomly-interstratified biotite-vermiculite. From the mineralogical studies, qualitative weathering processes for the schist are formulated. A probable mechanism for the intense chemical weathering of the schist appears to be oxidation of iron sulfides to form iron oxide-hydroxides, sulfates, and sulfuric acid. This natural weathering process is proposed as an analog to anthropogenic low pH rock weathering resulting from acid precipitation. In the Northeast, natural weathering rates, may, in places, significantly affect the water chemistry and mineralogy used to quantify total (natural plus anthropogenic) weathering and leaching rates. 27 references, 4 figures.

  18. From gene towards selective biomass valorization: bacterial β-etherases with catalytic activity on lignin-like polymers.

    PubMed

    Picart, Pere; Müller, Christoph; Mottweiler, Jakob; Wiermans, Lotte; Bolm, Carsten; Domínguez de María, Pablo; Schallmey, Anett

    2014-11-01

    Microbial β-etherases, which selectively cleave the β-O-4 aryl ether linkage present in lignin, hold great promise for future applications in lignin valorization. However, very few members have been reported so far and little is known about these enzymes. By using a database mining approach, four novel bacterial β-etherases were identified, recombinantly produced in Escherichia coli, and investigated together with known β-etherases in the conversion of various lignin and non-lignin-type model compounds. The resulting activities revealed the significant influence of the substituents at the phenyl ring adjacent to the ether bond. Finally, β-etherase activity on polymeric substrates, measured by using a fluorescently labeled synthetic lignin, was also proven; this underlined the applicability of the enzymes for the conversion of lignin into renewable chemicals. PMID:25186983

  19. Lignin blockers and uses thereof

    SciTech Connect

    Yang, Bin; Wyman, Charles E

    2013-11-12

    Disclosed is a method for converting cellulose in a lignocellulosic biomass. The method provides for a lignin-blocking polypeptide and/or protein treatment of high lignin solids. The treatment enhances cellulase availability in cellulose conversion and allows for the determination of optimized pretreatment conditions. Additionally, ethanol yields from a Simultaneous Saccharification and Fermentation process are improved 5-25% by treatment with a lignin-blocking polypeptide and/or protein.

  20. Identifying new lignin bioengineering targets: impact of epicatechin, quercetin glycoside, and gallate derivatives on the lignification and fermentation of maize cell walls

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Apoplastic targeting of secondary metabolites compatible with monolignol polymerization may provide new avenues for designing lignins that are less inhibitory toward fiber fermentation. To identify suitable monolignol substitutes, we artificially lignified maize cell walls with normal monolignols pl...

  1. Effects of acid precipitation and natural processes on cation leaching from four diverse forest ecosystems

    SciTech Connect

    Johnson, D.W.; Van Miegroet, H.; Cole, D.W.; Richter, D.D.

    1983-01-01

    Four forest ecosystems (two in eastern Tennessee and two in western Washington) with a history of intensive nutrient cycling research were selected for studies on the effects of acid precipitation and natural acid production processes on cation leaching rates. At the Tennessee sites, atmospheric acid input in bulk precipitation equaled or exceeded natural leaching by carbonic acid. At the less polluted Washington sites, natural leaching by carbonic acid was slightly larger than atmospheric acid input in the Douglas-fir soil. In the red alder soil, natural nitric acid formation far exceeded atmospheric acid inputs and appeared to have caused significant acidification of both soil and soil solution. The mobility of SO/sub 4//sup 2 -/ and NO/sub 3//sup -/ in these four soils was a major factor in their relative susceptibilities to leaching by H/sub 2/SO/sub 4/ and HNO/sub 3/ entering from the atmosphere. In two of the sites (chestnut oak in Tennessee and red alder in Washington), SO/sub 4//sup 2 -/ adsorption reduced the potential for sulfate-mediated leaching by H/sub 2/SO/sub 4/ by as much as one-half. Biological immobilization of NO/sub 3//sup -/ prevented leaching in all but the N-fixing red alder site. Both field and laboratory soil column studies involving artificial additions of SO/sub 4//sup 2 -/ and NO/sub 3//sup -/ verified the concept that cation leaching is controlled by the mobility of the associated anion.

  2. Potential effects of clean coal technologies on acid precipitation, greenhouse gases, and solid waste disposal

    SciTech Connect

    Blasing, T.J.; Miller, R.L.; McCold, L.N.

    1993-11-01

    The US Department of Energy`s (DOE`s) Clean Coal Technology Demonstration Program (CCTDP) was initially funded by Congress to demonstrate more efficient, economically feasible, and environmentally acceptable coal technologies. Although the environmental focus at first was on sulfur dioxide (SO{sub 2}) and nitrogen oxides (NO{sub x}) because their relationship to acid precipitation, the CCTDP may also lead to reductions in carbon dioxide (CO{sub 2}) emissions and in the volume of solid waste produced, compared with conventional technologies. The environmental effects of clean coal technologies (CCTs) depend upon which (if any) specific technologies eventually achieve high acceptance in the marketplace. In general, the repowering technologies and a small group of retrofit technologies show the most promise for reducing C0{sub 2} emissions and solid waste. These technologies also compare favorably with other CCTs in terms of SO{sub 2} and NO{sub x} reductions. The upper bound for CO{sup 2} reductions in the year 2010 is only enough to reduce global ``greenhouse`` warming potential by about 1%. However, CO{sub 2} emissions come from such variety of sources around the globe that no single technological innovation or national policy change could realistically be expected to reduce these emissions by more than a few percent. Particular CCTs can lead to either increases or decreases in the amount of solid waste produced. However, even if decreases are not achieved, much of the solid waste from clean coal technologies would be dry and therefore easier to dispose of than scrubber sludge.

  3. Potential health implications for acid precipitation, corrosion, and metals contamination of drinking water.

    PubMed Central

    Sharpe, W E; DeWalle, D R

    1985-01-01

    Potential health effects of drinking water quality changes caused by acid precipitation are presented. Several different types of water supply are discussed and their roles in modifying acid rain impacts on drinking water are explained. Sources of metals contamination in surface water supplies are enumerated. The authors present some results from their research into acid rain impacts on roof-catchment cisterns, small surface water supplies, and lead mobilization in acid soils. A good correlation was obtained between cistern water corrosivity as measured by the Ryznar Index (RI) values and standing tapwater copper concentrations. However, lead concentrations in tapwater did not correlate well with cistern water RI. A modified linear regression model that accounted for Ryznar Index change during storage in vinyl-lined cisterns was used to predict the Ryznar Index value at a copper concentration of 1000 micrograms/L. The predicted RI was greater than the RI of precipitation with a pH of 5.3, indicating that anthropogenically acidified precipitation may result in cistern tapwater copper concentrations in excess of the 1000 micrograms/L suggested drinking water limit. Good correlations between tapwater Ryznar Index and tapwater copper and lead concentrations were not obtained for the small surface water supply. Aluminum concentrations in reservoir water were similar to those in stream source water. Limited data were also presented that indicated lead was present in acid forest soil leachate and streams draining such soils in relatively small concentrations. Where appropriate, recommendations for future research are included with the discussions of research results. PMID:4076096

  4. Lignin amine microemulsions

    SciTech Connect

    DaGue, M.G.

    1992-03-10

    This patent describes a method of recovering hydrocarbons from an underground hydrocarbon formation having at least one injection well and at least one production well. It comprises injecting into the formation through an injection well a microemulsion comprising an internal phase of a primary amine having from about 8 to about 22 carbon atoms, lignin, a water soluble anionic surfactant, a solubilizer and an oil; and an external phase of brine comprising greater than about 90% by weight of the microemulsion; driving the microemulsion through the formation; and producing hydrocarbons through a production well.

  5. Model pathways in lignin thermolysis

    SciTech Connect

    Klein, M.T.; Virk, P.S.

    1981-02-01

    A fundamental description of lignin thermolysis was attempted. Analysis of the chemical topology of lignin suggested likely reaction pathways of import to lignin pyrolysis. In turn, 20 model compound pyrolysis substrates were selected to mimic the important reactive functional groups present in whole-lignin thermolysis. The more salient models were: phenethyl phenyl ether (PPE), which depicts the most prevalent lignin interunit linkage, guaiacol, model of the predominant aromatic methoxyl, and saligenol and cinnamyl alcohol, models of important propanoid side chains. Detailed pathway and kinetic analyses and determination of reaction Arrhenius parameters provided mechanistic insights into the model compound pyrolyses. Several pericyclic reaction mechanisms, hitherto not mentioned in the lignin pyrolysis literature, were suggested. In particular, PPE likely pyrolyses via a concerted retro-ene mechanism, whereas guaiacol and saligenol may respectively eliminate methane and water by concerted group transfers. A statistical interpretation of the lignin substrate coupled with the experimental model compound pyrolyses allowed simulation of whole-lignin thermolysis. The simulations were in substantial agreement with experimental pyrolyses reported in the literature in regard to overall gas, methane, carbon monoxide, individual phenols, and carbonaceous residue yields. Weight loss kinetics deduced from the time dependency of the latter yield also accorded well with the experimental literature.

  6. Engineering a monolignol 4-O-methyltransferase with high selectivity for the condensed lignin precursor coniferyl alchohol

    SciTech Connect

    Cai, Yuanheng; Shanklin, John; Mohammad -Wadud Bhuiya; Liu, Chang -Jun

    2015-09-16

    Lignin, a rigid biopolymer in plant cell walls, is derived from the oxidative polymerization of three monolignols. The composition of monolignol monomers dictates the degree of lignin condensation, reactivity, and thus the degradability of plant cell walls. Guaiacyl lignin is regarded as the condensed structural unit. Polymerization of lignin is initiated through the deprotonation of the para-hydroxyl group of monolignols. Therefore, preferentially modifying the para-hydroxyl of a specific monolignol to deprive its dehydrogenation propensity would disturb the formation of particular lignin subunits. Here, we test the hypothesis that specific remodeling the active site of a monolignol 4-O-methyltransferase would create an enzyme that specifically methylates the condensed guaiacyl lignin precursor coniferyl alcohol. Combining crystal structural information with combinatorial active site saturation mutagenesis and starting with the engineered promiscuous enzyme, MOMT5 (T133L/E165I/F175I/F166W/H169F), we incrementally remodeled its substrate binding pocket by the addition of four substitutions, i.e. M26H, S30R, V33S, and T319M, yielding a mutant enzyme capable of discriminately etherifying the para-hydroxyl of coniferyl alcohol even in the presence of excess sinapyl alcohol. The engineered enzyme variant has a substantially reduced substrate binding pocket that imposes a clear steric hindrance thereby excluding bulkier lignin precursors. Lastly, the resulting enzyme variant represents an excellent candidate for modulating lignin composition and/or structure in planta.

  7. Engineering a monolignol 4-O-methyltransferase with high selectivity for the condensed lignin precursor coniferyl alchohol

    DOE PAGESBeta

    Cai, Yuanheng; Shanklin, John; Mohammad -Wadud Bhuiya; Liu, Chang -Jun

    2015-09-16

    Lignin, a rigid biopolymer in plant cell walls, is derived from the oxidative polymerization of three monolignols. The composition of monolignol monomers dictates the degree of lignin condensation, reactivity, and thus the degradability of plant cell walls. Guaiacyl lignin is regarded as the condensed structural unit. Polymerization of lignin is initiated through the deprotonation of the para-hydroxyl group of monolignols. Therefore, preferentially modifying the para-hydroxyl of a specific monolignol to deprive its dehydrogenation propensity would disturb the formation of particular lignin subunits. Here, we test the hypothesis that specific remodeling the active site of a monolignol 4-O-methyltransferase would create anmore » enzyme that specifically methylates the condensed guaiacyl lignin precursor coniferyl alcohol. Combining crystal structural information with combinatorial active site saturation mutagenesis and starting with the engineered promiscuous enzyme, MOMT5 (T133L/E165I/F175I/F166W/H169F), we incrementally remodeled its substrate binding pocket by the addition of four substitutions, i.e. M26H, S30R, V33S, and T319M, yielding a mutant enzyme capable of discriminately etherifying the para-hydroxyl of coniferyl alcohol even in the presence of excess sinapyl alcohol. The engineered enzyme variant has a substantially reduced substrate binding pocket that imposes a clear steric hindrance thereby excluding bulkier lignin precursors. Lastly, the resulting enzyme variant represents an excellent candidate for modulating lignin composition and/or structure in planta.« less

  8. Engineering a monolignol 4-O-methyltransferase with high selectivity for the condensed lignin precursor coniferyl alcohol.

    PubMed

    Cai, Yuanheng; Bhuiya, Mohammad-Wadud; Shanklin, John; Liu, Chang-Jun

    2015-10-30

    Lignin, a rigid biopolymer in plant cell walls, is derived from the oxidative polymerization of three monolignols. The composition of monolignol monomers dictates the degree of lignin condensation, reactivity, and thus the degradability of plant cell walls. Guaiacyl lignin is regarded as the condensed structural unit. Polymerization of lignin is initiated through the deprotonation of the para-hydroxyl group of monolignols. Therefore, preferentially modifying the para-hydroxyl of a specific monolignol to deprive its dehydrogenation propensity would disturb the formation of particular lignin subunits. Here, we test the hypothesis that specific remodeling the active site of a monolignol 4-O-methyltransferase would create an enzyme that specifically methylates the condensed guaiacyl lignin precursor coniferyl alcohol. Combining crystal structural information with combinatorial active site saturation mutagenesis and starting with the engineered promiscuous enzyme, MOMT5 (T133L/E165I/F175I/F166W/H169F), we incrementally remodeled its substrate binding pocket by the addition of four substitutions, i.e. M26H, S30R, V33S, and T319M, yielding a mutant enzyme capable of discriminately etherifying the para-hydroxyl of coniferyl alcohol even in the presence of excess sinapyl alcohol. The engineered enzyme variant has a substantially reduced substrate binding pocket that imposes a clear steric hindrance thereby excluding bulkier lignin precursors. The resulting enzyme variant represents an excellent candidate for modulating lignin composition and/or structure in planta. PMID:26378240

  9. Polymeric microspheres

    DOEpatents

    Walt, David R.; Mandal, Tarun K.; Fleming, Michael S.

    2004-04-13

    The invention features core-shell microsphere compositions, hollow polymeric microspheres, and methods for making the microspheres. The microspheres are characterized as having a polymeric shell with consistent shell thickness.

  10. Modeling the neutralizing processes of acid precipitation in soils and glacial sediments of northern Ohio

    NASA Astrophysics Data System (ADS)

    Eckstein, Yoram; Hau, Joseph A.

    1992-02-01

    Most studies of the acidic deposition phenomena have been focused on processes occurring in the northeastern USA and Scandinavia. In these regions the soil cover is thin, the bedrock is acidic, and the terrain has very poor acid buffering capacity. Most of the US Midwest, including northern Ohio, has been ignored because the terrain is covered by glacial sediments with an abundance of carbonate minerals. Yet, for the last three decades the area has been experiencing acidic precipitation with a pH range of 3.5-4.5. the lowest in the USA. Samples of precipitation, soil water, and shallow ground water from Leroy Township in Lake County, Ohio, and from Wooster Township in Wayne County, Ohio, were analyzed and processed using WATEQ3 and PHREEQE computer models to quantify the effects of the acidic deposition. The two regions are characterized by very similar topographic, geological and hydrogeological conditions. Although the cation content of the precipitation in both regions is similar, the anion concentrations are much higher (sulfate by 70%, nitrate by 14% and chloride by 167%) in Leroy, located 50 km east-northeast and downwind of the Cleveland-Akron industrial complex, than in Wooster, located 80 km south-southwest and off-wind from the industrial complex. Computer modeling results indicate that buffering of acidic deposition in the surficial sediments and glacial tills of the two regions is dominated apparently by calcite dissolution, and dissolution and exchange of hydrogen for magnesium ions are the dominant neutralizing processes. However, reaction simulations also suggest that the buffering capacity of the Leroy soils and tills has been depleted to a much greater degree than in Wooster Township. In Leroy more acidic input is reacting with less buffering material to produce lower soil and groundwater pH. The depletion of carbonate and alumino-silicate minerals in the soils of Leroy Township is occurring at a rate that is 3-5 times faster than in the same type

  11. 21 CFR 573.600 - Lignin sulfonates.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Lignin sulfonates. 573.600 Section 573.600 Food... Additive Listing § 573.600 Lignin sulfonates. Lignin sulfonates may be safely used in animal feeds in... feeds, as liquid lignin sulfonate, in an amount not to exceed 11 percent of the molasses. (4) As...

  12. 21 CFR 573.600 - Lignin sulfonates.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Lignin sulfonates. 573.600 Section 573.600 Food... Additive Listing § 573.600 Lignin sulfonates. Lignin sulfonates may be safely used in animal feeds in... feeds, as liquid lignin sulfonate, in an amount not to exceed 11 percent of the molasses. (4) As...

  13. 21 CFR 573.600 - Lignin sulfonates.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Lignin sulfonates. 573.600 Section 573.600 Food... Additive Listing § 573.600 Lignin sulfonates. Lignin sulfonates may be safely used in animal feeds in... feeds, as liquid lignin sulfonate, in an amount not to exceed 11 percent of the molasses. (4) As...

  14. 21 CFR 573.600 - Lignin sulfonates.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Lignin sulfonates. 573.600 Section 573.600 Food... Additive Listing § 573.600 Lignin sulfonates. Lignin sulfonates may be safely used in animal feeds in... feeds, as liquid lignin sulfonate, in an amount not to exceed 11 percent of the molasses. (4) As...

  15. 21 CFR 573.600 - Lignin sulfonates.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Lignin sulfonates. 573.600 Section 573.600 Food... Additive Listing § 573.600 Lignin sulfonates. Lignin sulfonates may be safely used in animal feeds in... feeds, as liquid lignin sulfonate, in an amount not to exceed 11 percent of the molasses. (4) As...

  16. Towards the specification of consecutive steps in macromolecular lignin assembly

    NASA Technical Reports Server (NTRS)

    Nose, M.; Bernards, M. A.; Furlan, M.; Zajicek, J.; Eberhardt, T. L.; Lewis, N. G.

    1995-01-01

    When Pinus taeda cell suspension cultures are exposed to 8% sucrose solution, the cells undergo significant intracellular disruption, irregular wall thickening/lignification with concomitant formation of an 'extracellular lignin precipitate. However, addition of potassium iodide (KI), an H202 scavenger, inhibits this lignification response, while the ability to synthesize the monolignols, p-coumaryl and coniferyl alcohols, is retained. Lignin synthesis (i.e. polymerization) is thus temporarily correlated with H202 generation, strongly implying a regulatory role for the latter. Time course analyses of extracellular metabolites leading up to polymer formation reveal that coniferyl alcohol, but not p-coumaryl alcohol, undergoes substantial coupling reactions to give various lignans. Of these, the metabolites, dihydrodehydrodiconiferyl alcohol, shonanin (divanillyl tetrahydrofuran) and its apparent aryl tetralin derivative, cannot be explained simply on the basis of phenolic coupling. It is proposed that these moieties are the precursors of so-called reduced substructures in the lignin macromolecule. This adds a new perspective to the lignin assembly mechanism.

  17. The Influence of Zeolites on Radical Formation During Lignin Pyrolysis.

    PubMed

    Bährle, Christian; Custodis, Victoria; Jeschke, Gunnar; van Bokhoven, Jeroen A; Vogel, Frédéric

    2016-09-01

    Lignin from lignocellulosic biomass is a promising source of energy, fuels, and chemicals. The conversion of the polymeric lignin to fuels and chemicals can be achieved by catalytic and noncatalytic pyrolysis. The influence of nonporous silica and zeolite catalysts, such as silicalite, HZSM5, and HUSY, on the radical and volatile product formation during lignin pyrolysis was studied by in situ high-temperature electron paramagnetic resonance spectroscopy (HTEPR) as well as GC-MS. Higher radical concentrations were observed in the samples containing zeolite compared to the sample containing only lignin, which suggests that there is a stabilizing effect by the inorganic surfaces on the formed radical fragments. This effect was observed for nonporous silica as well as for HUSY, HZSM5, and silicalite zeolite catalysts. However, the effect is far larger for the zeolites owing to their higher specific surface area. The zeolites also showed an effect on the volatile product yield and the product distribution within the volatile phase. Although silicalite showed no effect on the product selectivity, the acidic zeolites such as HZSM5 or HUSY increased the formation of deoxygenated products such as benzene, toluene, xylene (BTX), and naphthalene. PMID:27486717

  18. Lignin oxidation by laccase isozymes from Trametes versicolor and role of the mediator 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) in kraft lignin depolymerization.

    PubMed Central

    Bourbonnais, R; Paice, M G; Reid, I D; Lanthier, P; Yaguchi, M

    1995-01-01

    Two laccase isozymes (I and II) produced by the white-rot fungus Trametes versicolor were purified, and their reactivities towards various substrates and lignins were studied. The N-terminal amino acid sequences of these enzymes were determined and compared to other known laccase sequences. Laccase II showed a very high sequence similarity to a laccase which was previously reported to depolymerize lignin. The reactivities of the two isozymes on most of the substrates tested were similar, but there were some differences in the oxidation rate of polymeric substrates. We found that the two laccases produced similar qualitative effects on kraft lignin and residual lignin in kraft pulp, with no evidence of a marked preference for depolymerization by either enzyme. However, the presence of the mediator 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) prevented and reversed the polymerization of kraft lignin by either laccase. The delignification of hardwood and softwood kraft pulps with the two isozymes and the mediator was compared; either laccase was able to reduce the kappa number of pulp, but only in the presence of 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate). PMID:7646025

  19. Transition-metal catalyzed valorization of lignin: the key to a sustainable carbon-neutral future.

    PubMed

    Kärkäs, Markus D; Matsuura, Bryan S; Monos, Timothy M; Magallanes, Gabriel; Stephenson, Corey R J

    2016-02-14

    The development of a sustainable, carbon-neutral biorefinery has emerged as a prominent scientific and engineering goal of the 21st century. As petroleum has become less accessible, biomass-based carbon sources have been investigated for utility in fuel production and commodity chemical manufacturing. One underutilized biomaterial is lignin; however, its highly crosslinked and randomly polymerized composition have rendered this biopolymer recalcitrant to existing chemical processing. More recently, insight into lignin's molecular structure has reinvigorated chemists to develop catalytic methods for lignin depolymerization. This review examines the development of transition-metal catalyzed reactions and the insights shared between the homogeneous and heterogeneous catalytic systems towards the ultimate goal of valorizing lignin to produce value-added products. PMID:26732312

  20. Epigallocatechin gallate incorporation into lignin enhances the alkaline delignification and enzymatic saccharification of cell walls

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Epigallocatechin gallate (EGCG) was evaluated as a potential lignin bioengineering target for rendering biomass more amenable to processing for biofuel production. In vitro peroxidase-catalyzed polymerization experiments revealed that both gallate and pyrogalloyl (B-ring) moieties in EGCG underwent ...

  1. Synthesis and characterization of lignin-based carbon materials with tunable microstructure

    SciTech Connect

    Chatterjee, Sabornie; Clingenpeel, Amy; McKenna, Amy; Rios, Orlando; Johs, Alexander

    2013-01-01

    Lignin-based carbons can be used as a low-cost alternative to graphite and petroleum-based carbons enabling the production of sustainable, functional carbon materials for various applications. The microstructure development of these carbons can be controlled through chemical modification of the lignin precursor and choice of carbonization parameters. In this work, microstructured carbon materials are synthesized from lignin using a combination of chemical modification and carbon fiber processing techniques. Lignin is modified by incorporating different ester groups which results in a precursor highly compatible with melt processing using the fiber extrusion technique and conversion into microstructured carbons by oxidative stabilization and subsequent carbonization. Furthermore, the impact of esterifications on precursor chemistry and carbonizations is investigated. A nuclear magnetic resonance study of modified lignins shows characteristic spectral changes as a result of esterifications. Ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry shows the modification process does not affect the polymeric character of the lignin backbone. Esterifications result in moderate shifts in O:C and H:C ratios. Thermogravimetric analysis of lignins reveals distinct differences in mass loss trends during oxidations and carbonizations.

  2. Degradation of carbohydrates during dilute sulfuric acid pretreatment can interfere with lignin measurements in solid residues.

    PubMed

    Katahira, Rui; Sluiter, Justin B; Schell, Daniel J; Davis, Mark F

    2013-04-01

    The lignin content measured after dilute sulfuric acid pretreatment of corn stover indicates more lignin than could be accounted for on the basis of the untreated corn stover lignin content. This phenomenon was investigated using a combination of (13)C cross-polarization/magic-angle spinning (CP/MAS) solid-state nuclear magnetic resonance (NMR) spectroscopy and lignin removal using acid chlorite bleaching. Only minimal contamination with carbohydrates and proteins was observed in the pretreated corn stover. Incorporating degradation products from sugars was also investigated using (13)C-labeled sugars. The results indicate that sugar degradation products are present in the pretreatment residue and may be intimately associated with the lignin. Studies comparing whole corn stover (CS) to extractives-free corn stover [CS(Ext)] clearly demonstrated that extractives are a key contributor to the high-lignin mass balance closure (MBC). Sugars and other low molecular weight compounds present in plant extractives polymerize and form solids during pretreatment, resulting in apparent Klason lignin measurements that are biased high. PMID:23428141

  3. Engineering Monolignol 4-O-Methyltransferases to Modulate Lignin Biosynthesis

    SciTech Connect

    Bhuiya, M.W.; Liu, C.

    2010-01-01

    Lignin is a complex polymer derived from the oxidative coupling of three classical monolignols. Lignin precursors are methylated exclusively at the meta-positions (i.e. 3/5-OH) of their phenyl rings by native O-methyltransferases, and are precluded from substitution of the para-hydroxyl (4-OH) position. Ostensibly, the para-hydroxyls of phenolics are critically important for oxidative coupling of phenoxy radicals to form polymers. Therefore, creating a 4-O-methyltransferase to substitute the para-hydroxyl of monolignols might well interfere with the synthesis of lignin. The phylogeny of plant phenolic O-methyltransferases points to the existence of a batch of evolutionarily 'plastic' amino acid residues. Following one amino acid at a time path of directed evolution, and using the strategy of structure-based iterative site-saturation mutagenesis, we created a novel monolignol 4-O-methyltransferase from the enzyme responsible for methylating phenylpropenes. We show that two plastic residues in the active site of the parental enzyme are vital in dominating substrate discrimination. Mutations at either one of these separate the evolutionarily tightly linked properties of substrate specificity and regioselective methylation of native O-methyltransferase, thereby conferring the ability for para-methylation of the lignin monomeric precursors, primarily monolignols. Beneficial mutations at both sites have an additive effect. By further optimizing enzyme activity, we generated a triple mutant variant that may structurally constitute a novel phenolic substrate binding pocket, leading to its high binding affinity and catalytic efficiency on monolignols. The 4-O-methoxylation of monolignol efficiently impairs oxidative radical coupling in vitro, highlighting the potential for applying this novel enzyme in managing lignin polymerization in planta.

  4. Expression of a bacterial 3-dehydroshikimate dehydratase reduces lignin content and improves biomass saccharification efficiency.

    PubMed

    Eudes, Aymerick; Sathitsuksanoh, Noppadon; Baidoo, Edward E K; George, Anthe; Liang, Yan; Yang, Fan; Singh, Seema; Keasling, Jay D; Simmons, Blake A; Loqué, Dominique

    2015-12-01

    Lignin confers recalcitrance to plant biomass used as feedstocks in agro-processing industries or as source of renewable sugars for the production of bioproducts. The metabolic steps for the synthesis of lignin building blocks belong to the shikimate and phenylpropanoid pathways. Genetic engineering efforts to reduce lignin content typically employ gene knockout or gene silencing techniques to constitutively repress one of these metabolic pathways. Recently, new strategies have emerged offering better spatiotemporal control of lignin deposition, including the expression of enzymes that interfere with the normal process for cell wall lignification. In this study, we report that expression of a 3-dehydroshikimate dehydratase (QsuB from Corynebacterium glutamicum) reduces lignin deposition in Arabidopsis cell walls. QsuB was targeted to the plastids to convert 3-dehydroshikimate - an intermediate of the shikimate pathway - into protocatechuate. Compared to wild-type plants, lines expressing QsuB contain higher amounts of protocatechuate, p-coumarate, p-coumaraldehyde and p-coumaryl alcohol, and lower amounts of coniferaldehyde, coniferyl alcohol, sinapaldehyde and sinapyl alcohol. 2D-NMR spectroscopy and pyrolysis-gas chromatography/mass spectrometry (pyro-GC/MS) reveal an increase of p-hydroxyphenyl units and a reduction of guaiacyl units in the lignin of QsuB lines. Size-exclusion chromatography indicates a lower degree of lignin polymerization in the transgenic lines. Therefore, our data show that the expression of QsuB primarily affects the lignin biosynthetic pathway. Finally, biomass from these lines exhibits more than a twofold improvement in saccharification efficiency. We conclude that the expression of QsuB in plants, in combination with specific promoters, is a promising gain-of-function strategy for spatiotemporal reduction of lignin in plant biomass. PMID:25583257

  5. Expression of a bacterial 3-dehydroshikimate dehydratase reduces lignin content and improves biomass saccharification efficiency

    DOE PAGESBeta

    Eudes, Aymerick; Sathitsuksanoh, Noppadon; Baidoo, Edward E. K.; George, Anthe; Liang, Yan; Yang, Fan; Singh, Seema; Keasling, Jay D.; Simmons, Blake A.; Loqué, Dominique

    2015-01-13

    Lignin confers recalcitrance to plant biomass used as feedstocks in agro-processing industries or as source of renewable sugars for the production of bioproducts. The metabolic steps for the synthesis of lignin building blocks belong to the shikimate and phenylpropanoid pathways. Genetic engineering efforts to reduce lignin content typically employ gene knockout or gene silencing techniques to constitutively repress one of these metabolic pathways. Recently, new strategies have emerged offering better spatiotemporal control of lignin deposition, including the expression of enzymes that interfere with the normal process for cell wall lignification. In this study, we report that expression of a 3-dehydroshikimatemore » dehydratase (QsuB from Corynebacterium glutamicum) reduces lignin deposition in Arabidopsis cell walls. QsuB was targeted to the plastids to convert 3-dehydroshikimate – an intermediate of the shikimate pathway – into protocatechuate. Compared to wild-type plants, lines expressing QsuB contain higher amounts of protocatechuate, p-coumarate, p-coumaraldehyde and p-coumaryl alcohol, and lower amounts of coniferaldehyde, coniferyl alcohol, sinapaldehyde and sinapyl alcohol. 2D-NMR spectroscopy and pyrolysis-gas chromatography/mass spectrometry (pyro-GC/MS) reveal an increase of p-hydroxyphenyl units and a reduction of guaiacyl units in the lignin of QsuB lines. Size-exclusion chromatography indicates a lower degree of lignin polymerization in the transgenic lines. Therefore, our data show that the expression of QsuB primarily affects the lignin biosynthetic pathway. Finally, biomass from these lines exhibits more than a twofold improvement in saccharification efficiency. We conclude that the expression of QsuB in plants, in combination with specific promoters, is a promising gain-of-function strategy for spatiotemporal reduction of lignin in plant biomass.« less

  6. Expression of a bacterial 3-dehydroshikimate dehydratase reduces lignin content and improves biomass saccharification efficiency

    SciTech Connect

    Eudes, Aymerick; Sathitsuksanoh, Noppadon; Baidoo, Edward E. K.; George, Anthe; Liang, Yan; Yang, Fan; Singh, Seema; Keasling, Jay D.; Simmons, Blake A.; Loqué, Dominique

    2015-01-13

    Lignin confers recalcitrance to plant biomass used as feedstocks in agro-processing industries or as source of renewable sugars for the production of bioproducts. The metabolic steps for the synthesis of lignin building blocks belong to the shikimate and phenylpropanoid pathways. Genetic engineering efforts to reduce lignin content typically employ gene knockout or gene silencing techniques to constitutively repress one of these metabolic pathways. Recently, new strategies have emerged offering better spatiotemporal control of lignin deposition, including the expression of enzymes that interfere with the normal process for cell wall lignification. In this study, we report that expression of a 3-dehydroshikimate dehydratase (QsuB from Corynebacterium glutamicum) reduces lignin deposition in Arabidopsis cell walls. QsuB was targeted to the plastids to convert 3-dehydroshikimate – an intermediate of the shikimate pathway – into protocatechuate. Compared to wild-type plants, lines expressing QsuB contain higher amounts of protocatechuate, p-coumarate, p-coumaraldehyde and p-coumaryl alcohol, and lower amounts of coniferaldehyde, coniferyl alcohol, sinapaldehyde and sinapyl alcohol. 2D-NMR spectroscopy and pyrolysis-gas chromatography/mass spectrometry (pyro-GC/MS) reveal an increase of p-hydroxyphenyl units and a reduction of guaiacyl units in the lignin of QsuB lines. Size-exclusion chromatography indicates a lower degree of lignin polymerization in the transgenic lines. Therefore, our data show that the expression of QsuB primarily affects the lignin biosynthetic pathway. Finally, biomass from these lines exhibits more than a twofold improvement in saccharification efficiency. We conclude that the expression of QsuB in plants, in combination with specific promoters, is a promising gain-of-function strategy for spatiotemporal reduction of lignin in plant biomass.

  7. Mechanochemical modification of lignin and application of the modified lignin for thermoplastics and thermosets

    NASA Astrophysics Data System (ADS)

    Guo, Xiaojie; Zhang, Jinwen; Xin, Junna

    In this work, mechanochemical modification of lignin and use of the modified lignin in thermoplastics and thermosets were studied. Oleated lignin was successfully prepared by transesterification between lignin and methyl, and the oleation reaction was performed in a solvent-free and room temperature ball milling process with a relatively short time. PLA/lignin blends were prepared through melt extrusion. Compared with the PLA/lignin blends, the PLA/oleated lignin blends exhibited finer dispersion of lignin in the blends, increased glass transition temperature and higher tensile properties, suggesting improved compatibility between lignin and PLA. Carboxylic and anhydride groups were also introduced into the structure of lignin via mechanochemical modification, and the resulting lignin derivatives were used as curing agents for epoxies. The dynamic mechanical properties and thermal stability of the cured epoxy resins were studied using dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA).

  8. Lignin-Derived Advanced Carbon Materials

    SciTech Connect

    Chatterjee, Sabornie; Saito, Tomonori

    2015-01-01

    Lignin is a highly abundant source of renewable carbon that can be considered as a valuable sustainable source of biobased materials. By application specific pretreatments and manufacturing method, lignin can be converted to a variety of value added carbon materials. However, the physical and chemical heterogenitites in lignin complicate its use as a feedstock. In this review, lignin manufacturing process, effects of pretreatments and manufacturing methods on the properties of lignin, properties and applications of various lignin derived carbon materials such as carbon fibers, carbon mats, activated carbons, carbon films; are discussed.

  9. Abnormal lignin in a loblolly pine mutant

    SciTech Connect

    Ralph, J.; MacKay, J.J.; Hatfield, R.D.

    1997-07-11

    Novel lignin is formed in a mutant loblolly pine (Pinus taeda L.) severely depleted in cinnamyl alcohol dehydrogenase (E.C. 1.1.1.195), which converts coniferaldehyde to coniferyl alcohol, the primary lignin precursor in pines. Dihydroconiferyl alcohol, a monomer not normally associated with the lignin biosynthetic pathway, is the major component of the mutant`s lignin, accounting for {approximately}30 percent (versus {approximately}3 percent in normal pine) of the units. The level of aldehydes, including new 2-methoxybenzaldehydes, is also increased. The mutant pines grew normally indicating that, even within a species, extensive variations in lignin composition need not disrupt the essential functions of lignin.

  10. Lignin-Derived Advanced Carbon Materials.

    PubMed

    Chatterjee, Sabornie; Saito, Tomonori

    2015-12-01

    Lignin is a highly abundant source of renewable carbon that can be considered as a valuable sustainable source of biobased materials. By applying specific pretreatments and manufacturing methods, lignin can be converted into a variety of value-added carbon materials. However, the physical and chemical heterogeneities of lignin complicate its use as a feedstock. Herein lignin manufacturing process, the effects of pretreatments and manufacturing methods on the properties of product lignin, and structure-property relationships in various applications of lignin-derived carbon materials, such as carbon fibers, carbon mats, activated carbons, carbon films, and templated carbon, are discussed. PMID:26568373

  11. Lignin-Derived Advanced Carbon Materials

    SciTech Connect

    Chatterjee, Sabornie; Saito, Tomonori

    2015-11-16

    Lignin is a highly abundant source of renewable carbon that can be considered as a valuable sustainable source of biobased materials. By applying specific pretreatments and manufacturing methods, it has been found that lignin can be converted into a variety of value-added carbon materials. However, the physical and chemical heterogeneities of lignin complicate its use as a feedstock. Herein, we discuss the lignin manufacturing process, the effects of pretreatments and manufacturing methods on the properties of product lignin, and structure–property relationships in various applications of lignin-derived carbon materials, such as carbon fibers, carbon mats, activated carbons, carbon films, and templated carbon.

  12. Does elevated N make lignin more recalcitrant?

    NASA Astrophysics Data System (ADS)

    Weintraub, M. N.; Rinkes, Z. L.; Grandy, S.; Wickings, K.; Bertrand, I.

    2014-12-01

    Increases in nitrogen (N) availability are often found to reduce decomposition rates of lignin-rich plant litter. However, the biological and chemical mechanisms that cause this inhibitory effect are still unclear. Our goal was to determine why increased N availability inhibits lignin decomposition. We tested two competing hypotheses: 1) decomposers degrade lignin to obtain protected N compounds and stop producing lignin-degrading enzymes if mineral N is available; or 2) chemical reactions between lignin and mineral N make lignin more recalcitrant, thereby limiting the ability of decomposers to break it down. To test these hypotheses, we followed changes in carbon (C) mineralization, microbial biomass and enzyme activities, litter chemistry, and lignin monomer concentrations over a 478-day laboratory incubation of three genotypes of maize stem internodes varying in litter quality. They were factorially combined with either an acidic or neutral pH sandy soil, with and without added N. Adding N reduced C mineralization, microbial biomass, and lignin-degrading enzyme activities in all treatments. Furthermore, our data on litter chemistry and lignin monomers indicate that N addition did not significantly alter the quantity or quality of lignin in any treatment. These results suggest that abiotic interactions between N and lignin compounds did not alter the ability of decomposers to breakdown lignin. Thus, we conclude that mineral N alters microbial enzyme and biomass dynamics, but not lignin chemistry during maize decomposition.

  13. The fate of lignin during hydrothermal pretreatment

    PubMed Central

    2013-01-01

    Background Effective enzymatic hydrolysis of lignocellulosic biomass benefits from lignin removal, relocation, and/or modification during hydrothermal pretreatment. Phase transition, depolymerization/repolymerization, and solubility effects may all influence these lignin changes. To better understand how lignin is altered, Populus trichocarpa x P. deltoides wood samples and cellulolytic enzyme lignin (CEL) isolated from P. trichocarpa x P. deltoides were subjected to batch and flowthrough pretreatments. The residual solids and liquid hydrolysate were characterized by gel permeation chromatography, heteronuclear single quantum coherence NMR, compositional analysis, and gas chromatography–mass spectrometry. Results Changes in the structure of the solids recovered after the pretreatment of CEL and the production of aromatic monomers point strongly to depolymerization and condensation being primary mechanisms for lignin extraction and redeposition. The differences in lignin removal and phenolic compound production from native P. trichocarpa x P. deltoides and CEL suggested that lignin-carbohydrate interactions increased lignin extraction and the extractability of syringyl groups relative to guaiacyl groups. Conclusions These insights into delignification during hydrothermal pretreatment point to desirable pretreatment strategies and plant modifications. Because depolymerization followed by repolymerization appears to be the dominant mode of lignin modification, limiting the residence time of depolymerized lignin moieties in the bulk liquid phase should reduce lignin content in pretreated biomass. In addition, the increase in lignin removal in the presence of polysaccharides suggests that increasing lignin-carbohydrate cross-links in biomass would increase delignification during pretreatment. PMID:23902789

  14. Lignin-assisted coal depolymerization

    SciTech Connect

    Lalvani, S.B.

    1991-01-01

    Previous research has shown that addition of lignin-derived liquids to coal stirred in tetralin under mild reaction conditions (375{degree}C and 300--500 psig) results in a marked enhancement in the rate of coal depolymerization. A mathematical model was developed to study the kinetics of coal depolymerization in the presence of liquid-derived liquids. In the present study, a reaction pathway was formulated to explain the enhancement in coal depolymerization due to lignin (solid) addition. The model postulated assumes that the products of lignin obtained during thermolysis interact with the reactive moieties present in coal while simultaneous depolymerization of coal occurs. A good fit between the experimental data and the kinetic model was found. The results show that in addition to the enhancement in the rate of coal depolymerization, lignin also reacts (and enhances the extent of depolymerization of coal) with those reaction sites in coal that are not susceptible to depolymerization when coal alone is reacted in tetralin under identical reaction conditions. Additional work is being carried out to determine a thorough materials balance on the lignin-assisted coal depolymerization process. A number of liquid samples have been obtained which are being studied for their stability in various environments. 5 refs., 4 figs., 1 tab.

  15. ISSUES IN LIGNIN CHEMISTRY. "THE HELSINKI CONNECTION"

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This presentation covers advances in lignin chemistry (and our Helsinki connection) on dibenzodioxocins, spirodienones, and reduced structures in lignins. It also explores the various roles in defending lignification theory (based on Freudenberg's original hypothesis) against a supposed new contende...

  16. Lignin analysis by FT-Raman spectroscopy

    SciTech Connect

    Agarwal, U.P.; Obst, J.R.; Cannon, A.B.

    1996-10-01

    Traditional methods of lignin analysis, such as Klason (acid insoluble) lignin determinations, give satisfactory results, are widely accepted, and often are considered as standard analyses. However, the Klason lignin method is laborious and time consuming; it also requires a fairly large-amount of isolated analyte. FT-Raman spectroscopy offers an opportunity to simplify and speed up lignin analyses. FT-Raman data for a number of hardwoods (angiosperms) and softwoods (gymnosperms) are compared with data obtained using other analytical methods, including Klason lignin (with corrections for acid soluble lignin), acetyl bromide, and FT-IR determinations. In addition, 10 different specimens of Nothofagus dombeyii (chosen because of the widely varying syringyl:guaiacyl monomer compositions of their lignins) were also analyzed. Lignin monomer compositions were determined by thioacidolysis of by nitrobenzene oxidation.

  17. Fate of Residual Lignin during Delignification of Kraft Pulp by Trametes versicolor

    PubMed Central

    Reid, Ian D.

    1998-01-01

    The fungus Trametes versicolor can delignify and brighten kraft pulps. To better understand the mechanism of this biological bleaching and the by-products formed, I traced the transformation of pulp lignin during treatment with the fungus. Hardwood and softwood kraft pulps containing 14C-labelled residual lignin were prepared by laboratory pulping of lignin-labelled aspen and spruce wood and then incubated with T. versicolor. After initially polymerizing the lignin, the fungus depolymerized it to alkali-extractable forms and then to soluble forms. Most of the labelled carbon accumulated in the water-soluble pool. The extractable and soluble products were oligomeric; single-ring aromatic products were not detected. The mineralization of the lignin carbon to CO2 varied between experiments, up to 22% in the most vigorous cultures. The activities of the known enzymes laccase and manganese peroxidase did not account for all of the lignin degradation that took place in the T. versicolor cultures. This fungus may produce additional enzymes that could be useful in enzyme bleaching systems. PMID:9603823

  18. [Preparation of spherical lignin cation adsorption resin with black pulping liquor].

    PubMed

    Liu, Ming-Hua; Zou, Jin-Guang; Hong, Shu-Nan; Zeng, Zhen-Ou

    2005-09-01

    Spherical lignin cation adsorption resin was obtained by two-step method with black liquor of paper mill and characterized by the Scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FTIR). Firstly, the spherical lignin beads were prepared with black liquor of paper mill by applying reverse-phase suspension polymerization technique, and the preparation conditions were also optimized. The suitable conditions include 200 r/min of stirring speed, 90 degrees C of reaction temperature, 1.0 h of reaction time and use epoxy chloropropane (1.5% by weight of lignin) as cross-linking agent, the ideal volume ratio between oil phase and water phase was 3:1 by using kerosene oil as disperse phase, and the perfect dispersant agent was Tween 80 (3% by weight of lignin). Secondly, the spherical lignin cation adsorption resin was developed by grafting the acrylamide onto the back-bone of the spherical lignin beads. The best concentration of acrylamide was 0.72 mol/L at ambient temperature for 2.0 h, and the ideal initiator system was the Fenton reagent of H2O2/Fe2+. Under the above conditions, the ion exchange capacity of the prepared resin could reach 1.640 5 mmol/g. PMID:16366482

  19. Lignin degradation during plant litter photodegradation

    NASA Astrophysics Data System (ADS)

    Lin, Y.; King, J. Y.

    2014-12-01

    Lignin is the second most abundant compound, after cellulose, synthesized by plants. Numerous studies have demonstrated that initial lignin concentration is negatively correlated with litter decomposition rate under both laboratory and field conditions. Thus lignin is commonly considered to be a "recalcitrant" compound during litter decomposition. However, lignin can also serve as a radiation-absorbing compound during photodegradation, the process through which solar radiation breaks down organic matter. Here, we synthesize recent studies concerning lignin degradation during litter photodegradation and report results from our study on how photodegradation changes lignin chemistry at a molecular scale. Recent field studies have found that litter with high initial lignin concentration does not necessarily exhibit high mass loss during photodegradation. A meta-analysis (King et al. 2012) even found a weak negative correlation between initial lignin concentration and photodegradation rate. Contradicting results have been reported with regard to the change in lignin concentration during photodegradation. Some studies have found significant loss of lignin during photodegradation, while others have not. In most studies, loss of lignin only accounts for a small proportion of the overall mass loss. Using NMR spectroscopy, we found significant loss of lignin structural units containing beta-aryl ether linkages during photodegradation of a common grass litter, Bromus diandrus, even though conventional forage fiber analysis did not reveal changes in lignin concentration. Both our NMR and fiber analyses supported the idea that photodegradation induced loss of hemicellulose, which was mainly responsible for the litter mass loss during photodegradation. Our results suggest that photodegradation induces degradation, but not necessarily complete breakdown, of lignin structures and consequently exposes hemicellulose and cellulose to microbial decomposition. We conclude that lignin

  20. Development of novel assays for lignin degradation: comparative analysis of bacterial and fungal lignin degraders.

    PubMed

    Ahmad, Mark; Taylor, Charles R; Pink, David; Burton, Kerry; Eastwood, Daniel; Bending, Gary D; Bugg, Timothy D H

    2010-05-01

    Two spectrophotometric assays have been developed to monitor breakdown of the lignin component of plant lignocellulose: a continuous fluorescent assay involving fluorescently modified lignin, and a UV-vis assay involving chemically nitrated lignin. These assays have been used to analyse lignin degradation activity in bacterial and fungal lignin degraders, and to identify additional soil bacteria that show activity for lignin degradation. Two soil bacteria known to act as aromatic degraders, Pseudomonas putida and Rhodococcus sp. RHA1, consistently showed activity in these assays, and these strains were shown in a small scale experiment to breakdown lignocellulose, producing a number of monocyclic phenolic products. Using milled wood lignin prepared from wheat straw, pine, and miscanthus, some bacterial lignin degraders were found to show specificity for lignin type. These assays could be used to identify novel lignin degraders for breakdown of plant lignocellulose. PMID:20567767

  1. Liquid Fuels from Lignins: Annual Report

    SciTech Connect

    Chum, H. L.; Johnson, D. K.

    1986-01-01

    This task was initiated to assess the conversion of lignins into liquid fuels, primarily of lignins relevant to biomass-to-ethanol conversion processes. The task was composed of a literature review of this area and an experimental part to obtain pertinent data on the conversion of lignins germane to biomass-to-ethanol conversion processes.

  2. 40 CFR 721.5460 - Organosolv lignin.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Organosolv lignin. 721.5460 Section... Substances § 721.5460 Organosolv lignin. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as an organosolv lignin (PMN P-95-1584; CAS No. 8068-03-9)...

  3. 40 CFR 721.5460 - Organosolv lignin.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Organosolv lignin. 721.5460 Section... Substances § 721.5460 Organosolv lignin. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as an organosolv lignin (PMN P-95-1584; CAS No. 8068-03-9)...

  4. 40 CFR 721.5460 - Organosolv lignin.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Organosolv lignin. 721.5460 Section... Substances § 721.5460 Organosolv lignin. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as an organosolv lignin (PMN P-95-1584; CAS No. 8068-03-9)...

  5. 40 CFR 721.5460 - Organosolv lignin.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Organosolv lignin. 721.5460 Section... Substances § 721.5460 Organosolv lignin. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as an organosolv lignin (PMN P-95-1584; CAS No. 8068-03-9)...

  6. 40 CFR 721.5460 - Organosolv lignin.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Organosolv lignin. 721.5460 Section... Substances § 721.5460 Organosolv lignin. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as an organosolv lignin (PMN P-95-1584; CAS No. 8068-03-9)...

  7. Cationic electrodepositable coating composition comprising lignin

    DOEpatents

    Fenn, David; Bowman, Mark P; Zawacky, Steven R; Van Buskirk, Ellor J; Kamarchik, Peter

    2013-07-30

    A cationic electrodepositable coating composition is disclosed. The present invention in directed to a cationic electrodepositable coating composition comprising a lignin-containing cationic salt resin, that comprises (A) the reaction product of: lignin, an amine, and a carbonyl compound; (B) the reaction product of lignin, epichlorohydrin, and an amine; or (C) combinations thereof.

  8. Polymerization catalyst

    SciTech Connect

    Graves, V.

    1987-05-12

    A process is described for polymerizing at least one alpha olefin under conditions characteristic of Ziegler polymerization wherein the polymerization is conducted in the presence of a catalyst system which comprises: a supported catalyst prepared under anhydrous conditions by the sequential steps of: preparing a slurry of inert particulate support material; adding to the slurry a solution of an organomagnesium compound; adding to the slurry and reacting a solution of a zirconium halide compound, hafnium compound or mixtures thereof; adding to the slurry and reacting a halogenator; adding to the slurry and reacting a tetravalent titanium halide compound; and recovering solid catalyst.

  9. Polymerization catalyst

    SciTech Connect

    Graves, V.

    1986-10-21

    A process is described for polymerizing at least one alpha-olefin under conditions characteristic of Ziegler polymerization wherein the polymerization is conducted in the presence of a catalyst comprising: a supported catalyst prepared under anhydrous conditions by the steps of: (1) sequentially; (a) preparing a slurry of inert particulate support material; (b) adding to the slurry a solution of an organomagnesium compound; (c) adding to the slurry and reacting a solution of zirconium compound; and (2) thereafter; (d) adding to the slurry and reacting a halogenator; (e) adding to the slurry and reacting a tetravalent titanium compound; (f) recovering solid catalyst; and an organoaluminum compound.

  10. Enzymatic monitoring of lignin and lignin derivatives biooxidation.

    PubMed

    Ibrahim, Victor; Mamo, Gashaw

    2016-01-01

    Lignin oxidation was enzymatically monitored by measuring methanol released during the reaction. The methanol was oxidized to formaldehyde and hydrogen peroxide, and the latter used to oxidize ABTS to a product measured spectrophotometrically. The efficiency was comparable to the commonly used gas chromatography method. The assay was fast and inexpensive. PMID:26632344

  11. Integrated Lake-Watershed Acidification Study (ILWAS): contributions to the international conference on the ecological impact of acid precipitation

    SciTech Connect

    Not Available

    1981-05-01

    The Integrated Lake-Watershed Acidification Study (ILWAS) was initiated to study and detail lake acidification processes for three lake watershed basins in the Adirondack Park region of New York. The three basins (Woods, Sagamore, and Panther), receive similar amounts of acid deposition yet observable pH values for the lakes are very dissimilar indicating unequal acid neutralizing capacities among the watersheds. This volume contains a compilation of seven papers. Relevant topics include: a characterization of the geology, hydrology, limnology and vegetation of the three study sites, an analysis of acid precipitation quality and quantity, the effects of vegetative canopy, the effects of snowmelt, the effects of winter lake stratification, comparison of heavy metal transport, examination of acidic sources other than direct precipitation, assessment of lake acidification during spring thaw and integration of all acidification components with a mathematical model.

  12. Biogeochemical effects of forest vegetation on acid precipitation-related water chemistry: a case study in southwest China.

    PubMed

    Chen, Jing; Li, Wei; Gao, Fang

    2010-10-01

    The elemental composition of rainwater, throughfall, and soil solutions of a forest ecosystem in the acid rain control region of southwest China was investigated during 2007-2008 to assess the acid buffering capacity of different forest covers. A possible seasonal distribution of wet deposition was identified. Sulfur was determined as the dominant acidification precursor in this region. The chemical composition of rainfall intercepted by the forest canopy was modified substantially; generally the ion concentrations were increased by dry deposition and foliar leaching. As an exception, the concentration of NH(4)(+) and NO(3)(-) decreased in throughfall, which was probably due to the absorption of nitrogen by the leaves. Elemental concentrations in soil solutions decreased with depth. The water conservation capacity of different forests was also evaluated. The most appropriate forest vegetation for water conservation and remediation of acid precipitation in this region was explored for the sake of ecosystem management, ecological restoration and economic development. PMID:20859590

  13. VARIABILITY OF GRASS LIGNIN ACYLATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grasses are being championed as biomass sources for bioenergy production. Their ultimate use would be as a source of carbohydrate for fermentation to ethanol, conversion to oils via pyrolysis, or direct conversion to energy through combustion. In the latter case, increasing lignin content would enha...

  14. Towards development of lignin reinforced elastomeric compounds with reduced energy dissipation

    NASA Astrophysics Data System (ADS)

    Bahl, Kushal

    This research deals with development of lignin as reinforcing filler for elastomeric compounds. Lignins are naturally abundant and cost competitive wood derivatives possessing strong mechanical properties and offering reactive functional groups on their surfaces. The presence of the functional groups imparts polarity to the lignin molecules and makes them incompatible with non-polar elastomers. Also, the large particle size of lignin does not produce desired mechanical reinforcement. The present study deals with solving the outstanding issues associated with the use of lignin as fillers for polymeric compounds. In addition, the work specifically focuses on producing rubber compounds with reduced energy dissipation via partial replacement of carbon black with lignin. The first part of this study is devoted to suppression of the polarity of lignin and achievement of compatibility with rubber matrix via modification of lignosulfonates (LS) with cyclohexylamine (CA). CA reduces the polarity of lignin via interactions originating from proton transfer and hydrogen bonding. X-ray Photoelectron Spectroscopy (XPS) confirms the attachment of CA on the surfaces of lignin. The mechanical properties of rubber compounds increase substantially along with improvement in cure properties and increase in crosslink density in the presence of LS particles modified with CA. The tensile strength and storage modulus show an increase by 45% and 41% respectively. The values of the 100% modulus and elongation at break also improve by 35% and 60% respectively. The second part of this study exploits the non-covalent interactions between lignin and carbon black (CB) for the design of novel hybrid filler particles exhibiting lower energy loss in rubber compounds. The hybrid fillers offer unique morphology consisting of coating layers of lignin on carbon black particle aggregates. It is found that such coating layers are formed due to pi-pi interactions between lignin and carbon black. Raman

  15. Isolation and structural characterization of the milled wood lignin, dioxane lignin, and cellulolytic lignin preparations from brewer's spent grain.

    PubMed

    Rencoret, Jorge; Prinsen, Pepijn; Gutiérrez, Ana; Martínez, Ángel T; Del Río, José C

    2015-01-21

    The structure of the lignin from brewer's spent grain (BSG) has been studied in detail. Three different lignin preparations, the so-called "milled-wood" lignin (MWL), dioxane lignin (DL), and cellulolytic lignin (CEL), were isolated from BSG and then thoroughly characterized by pyrolysis GC/MS, 2D-NMR, and derivatization followed by reductive cleavage (DFRC). The data indicated that BSG lignin presents a predominance of guaiacyl units (syringyl/guaiacyl ratio of 0.4-0.5) with significant amounts of associated p-coumarates and ferulates. The flavone tricin was also present in the lignin from BSG, as also occurred in other grasses. 2D-NMR (HSQC) revealed that the main substructures present are β-O-4' alkyl-aryl ethers (77-79%) followed by β-5' phenylcoumarans (11-13%) and lower amounts of β-β' resinols (5-6%) and 5-5' dibenzodioxocins (3-5%). The results from 2D-NMR (HMBC) and DFRC indicated that p-coumarates are acylating the γ-carbon of lignin side chains and are mostly involved in condensed structures. DFRC analyses also indicated a minor degree of γ-acylation with acetate groups, which takes place preferentially on S lignin (6% of S units are acetylated) over G lignin (only 1% of G units are acetylated). PMID:25520237

  16. Physicochemical and structural characterization of alkali soluble lignins from oil palm trunk and empty fruit-bunch fibers.

    PubMed

    Sun, R; Fang, J M; Tomkinson, J; Bolton, J

    1999-07-01

    Six alkali soluble lignin fractions were extracted from the cell wall materials of oil palm trunk and empty fruit-bunch (EFB) fibers with 5% NaOH, 10% NaOH, and 24% KOH/2% H(3)BO(3). All of the lignin fractions contained rather low amounts of associated neutral sugars (0.8-1.2%) and uronic acids (1.1-2.0%). The lignin fractions isolated with 5% NaOH from the lignified palm trunk and EFB fibers gave a relatively higher degree of polymerization as shown by weight-average molecular weights ranging between 2620 and 2840, whereas the lignin fractions isolated with 10% NaOH and 24% KOH/2% H(3)BO(3) from the partially delignified palm trunk and EFB fibers showed a relatively lower degree of polymerization, as shown by weight-average molecular weights ranging between 1750 and 1980. The results obtained by alkaline nitrobenzene oxidation showed that all of the lignin preparations contained a high proportion of noncondensed syringyl units with small amounts of noncondensed guaiacyl and fewer p-hydroxyphenyl units. The lignin fraction extracted with 5% NaOH from the lignified EFB fiber was mainly composed of beta-O-4 ether-linked units. Small amounts of 5-5', beta-5, and beta-beta' carbon-carbon linkages were also found to be present between the lignin structural units. Further studies showed that uronic, p-hydroxybenzoic, and ferulic acids in the cell walls of palm fibers were esterified to lignin. PMID:10552589

  17. Polymeric nanoparticles

    PubMed Central

    Bolhassani, Azam; Javanzad, Shabnam; Saleh, Tayebeh; Hashemi, Mehrdad; Aghasadeghi, Mohammad Reza; Sadat, Seyed Mehdi

    2014-01-01

    Nanocarriers with various compositions and biological properties have been extensively applied for in vitro/in vivo drug and gene delivery. The family of nanocarriers includes polymeric nanoparticles, lipid-based carriers (liposomes/micelles), dendrimers, carbon nanotubes, and gold nanoparticles (nanoshells/nanocages). Among different delivery systems, polymeric carriers have several properties such as: easy to synthesize, inexpensive, biocompatible, biodegradable, non-immunogenic, non-toxic, and water soluble. In addition, cationic polymers seem to produce more stable complexes led to a more protection during cellular trafficking than cationic lipids. Nanoparticles often show significant adjuvant effects in vaccine delivery since they may be easily taken up by antigen presenting cells (APCs). Natural polymers such as polysaccharides and synthetic polymers have demonstrated great potential to form vaccine nanoparticles. The development of new adjuvants or delivery systems for DNA and protein immunization is an expanding research field. This review describes polymeric carriers especially PLGA, chitosan, and PEI as vaccine delivery systems. PMID:24128651

  18. Simultaneously disrupting AtPrx2, AtPrx25 and AtPrx71 alters lignin content and structure in Arabidopsis stem.

    PubMed

    Shigeto, Jun; Itoh, Yoshitaka; Hirao, Sakie; Ohira, Kaori; Fujita, Koki; Tsutsumi, Yuji

    2015-04-01

    Plant class III heme peroxidases catalyze lignin polymerization. Previous reports have shown that at least three Arabidopsis thaliana peroxidases, AtPrx2, AtPrx25 and AtPrx71, are involved in stem lignification using T-DNA insertion mutants, atprx2, atprx25, and atprx71. Here, we generated three double mutants, atprx2/atprx25, atprx2/atprx71, and atprx25/atprx71, and investigated the impact of the simultaneous deficiency of these peroxidases on lignins and plant growth. Stem tissue analysis using the acetyl bromide method and derivatization followed by reductive cleavage revealed improved lignin characteristics, such as lowered lignin content and increased arylglycerol-β-aryl (β-O-4) linkage type, especially β-O-4 linked syringyl units, in lignin, supporting the roles of these genes in lignin polymerization. In addition, none of the double mutants exhibited severe growth defects, such as shorter plant stature, dwarfing, or sterility, and their stems had improved cell wall degradability. This study will contribute to progress in lignin bioengineering to improve lignocellulosic biomass. PMID:25644691

  19. An Engineered Monolignol 4-O-Methyltransferase Depresses Lignin Biosynthesis and Confers Novel Metabolic Capability in Arabidopsis[C][W][OA

    PubMed Central

    Zhang, Kewei; Bhuiya, Mohammad-Wadud; Pazo, Jorge Rencoret; Miao, Yuchen; Kim, Hoon; Ralph, John; Liu, Chang-Jun

    2012-01-01

    Although the practice of protein engineering is industrially fruitful in creating biocatalysts and therapeutic proteins, applications of analogous techniques in the field of plant metabolic engineering are still in their infancy. Lignins are aromatic natural polymers derived from the oxidative polymerization of primarily three different hydroxycinnamyl alcohols, the monolignols. Polymerization of lignin starts with the oxidation of monolignols, followed by endwise cross-coupling of (radicals of) a monolignol and the growing oligomer/polymer. The para-hydroxyl of each monolignol is crucial for radical generation and subsequent coupling. Here, we describe the structure-function analysis and catalytic improvement of an artificial monolignol 4-O-methyltransferase created by iterative saturation mutagenesis and its use in modulating lignin and phenylpropanoid biosynthesis. We show that expressing the created enzyme in planta, thus etherifying the para-hydroxyls of lignin monomeric precursors, denies the derived monolignols any participation in the subsequent coupling process, substantially reducing lignification and, ultimately, lignin content. Concomitantly, the transgenic plants accumulated de novo synthesized 4-O-methylated soluble phenolics and wall-bound esters. The lower lignin levels of transgenic plants resulted in higher saccharification yields. Our study, through a structure-based protein engineering approach, offers a novel strategy for modulating phenylpropanoid/lignin biosynthesis to improve cell wall digestibility and diversify the repertories of biologically active compounds. PMID:22851762

  20. Potentiometric chemical sensors from lignin-poly(propylene oxide) copolymers doped by carbon nanotubes.

    PubMed

    Rudnitskaya, Alisa; Evtuguin, Dmitry V; Costa, Luis C; Graça, M Pedro F; Fernandes, António J S; Correia, M Rosario P; Gomes, M Teresa S R; Oliveira, J A B P

    2013-01-21

    Hardwood and softwood lignins obtained from industrial sulphite and kraft and laboratory oxygen-organosolv pulping processes were employed in co-polymerization with tolylene 2,4-diisocyanate terminated poly(propylene glycol). The obtained lignin-based polyurethanes were doped with 0.72 w/w% of multiwall carbon nanotubes (MWCNTs) with the aim of increasing their electrical conductivity to the levels suitable for sensor applications. Effects of the polymer doping with MWCNTs were assessed using electrical impedance (EIS) and UV-Resonance Raman (UV-RR) spectroscopy. Potentiometric sensors were prepared by drop casting of liquid polymer on the surface of carbon glass or platinum electrodes. Lignin-based sensors displayed a very low or no sensitivity to all alkali, alkali-earth and transition metal cations ions except Cr(VI) at pH 2. Response to Cr(VI) values of 39, 50 and 53 mV pX(-1) for the sensors based on kraft, organosolv and lignosulphonate lignins, respectively, were observed. Redox sensitivity values close to the theoretical values of 20 and 21 mV pX(-1) for organosolv and lignosulphonate based sensors respectively were detected in the Cr(III)/Cr(VI) solutions while a very low response was observed in the solutions containing Fe(CN)(6)(3-/4-). Conducting composite lignin-based polyurethanes doped with MWCNTs were suggested as being promising materials for Cr(VI)-sensitive potentiometric sensors. PMID:23162814

  1. Reaction chemistry and phase behavior of lignin in high-temperature and supercritical water.

    PubMed

    Fang, Zhen; Sato, Takafumi; Smith, Richard L; Inomata, Hiroshi; Arai, Kunio; Kozinski, Janusz A

    2008-06-01

    Decomposition of organosolve lignin in water/phenol solutions was studied in a 50 nL micro-reactor coupled with optical, Raman and infrared microscopies at temperatures up to 600 degrees C and water densities up to 1165 kg/m3. It was found that when phenol was used with {lignin+water} mixtures that a homogenous phase was formed that seemed to promote the decomposition of lignin into phenolic fragments by hydrolysis and pyrolysis. Phenol, along with the homogenous reaction conditions also inhibited re-polymerization of the phenolics and promoted oil formation. On the other hand, in the absence of phenol, lignin remained as a heterogeneous phase with water over the range of conditions studied. The homogeneous conditions and conditions for inhibiting char formation by phenol were elucidated and it was found that mixtures of phenol and lignin become homogeneous at 400-600 degrees C and high water densities of 428-683 kg/m3, corresponding to maximum pressures of 93 MPa. These results were further used to propose reaction paths. PMID:17881227

  2. Unravelling lignin formation and structure. Final report, April 1, 1988--March 31, 1991

    SciTech Connect

    Lewis, N.G.

    1991-12-31

    During this study, we established that the Fagaceae exclusively accumulate Z-monolignois/glucosides, and not the E-isomers. Evidence for the presence of a novel E{yields}Z isomerse has been obtained. Our pioneering work in lignin biosynthesis and structure in situ has also progressed smoothly. We established the bonding environments of a woody angiosperm, Leucanea leucocephala, as well as wheat (T. aestivum) and tobacco (N. tabacum). A cell culture system from Pinus taeda was developed which seems ideal for investigating the early stages of lignification. These cultures excrete peroxidase isozymes, considered to be specifically involved in lignin deposition. We also studied the effect of the putative lignin-degrading enzyme, lignin peroxidase, on monolignols and dehydropolymerisates therefrom. In all cases, polymerization was observed, and not degradation; these polymers are identical to that obtained with horseradish peroxidases/H{sub 2}O{sub 2}. It seems inconceivable that these enzymes can be considered as being primarily responsible for lignin biodegradation.

  3. Epigallocatechin gallate incorporation into lignin enhances the alkaline delignification and enzymatic saccharification of cell walls

    PubMed Central

    2012-01-01

    Background Lignin is an integral component of the plant cell wall matrix but impedes the conversion of biomass into biofuels. The plasticity of lignin biosynthesis should permit the inclusion of new compatible phenolic monomers such as flavonoids into cell wall lignins that are consequently less recalcitrant to biomass processing. In the present study, epigallocatechin gallate (EGCG) was evaluated as a potential lignin bioengineering target for rendering biomass more amenable to processing for biofuel production. Results In vitro peroxidase-catalyzed polymerization experiments revealed that both gallate and pyrogallyl (B-ring) moieties in EGCG underwent radical cross-coupling with monolignols mainly by β–O–4-type cross-coupling, producing benzodioxane units following rearomatization reactions. Biomimetic lignification of maize cell walls with a 3:1 molar ratio of monolignols and EGCG permitted extensive alkaline delignification of cell walls (72 to 92%) that far exceeded that for lignified controls (44 to 62%). Alkali-insoluble residues from EGCG-lignified walls yielded up to 34% more glucose and total sugars following enzymatic saccharification than lignified controls. Conclusions It was found that EGCG readily copolymerized with monolignols to become integrally cross-coupled into cell wall lignins, where it greatly enhanced alkaline delignification and subsequent enzymatic saccharification. Improved delignification may be attributed to internal trapping of quinone-methide intermediates to prevent benzyl ether cross-linking of lignin to structural polysaccharides during lignification, and to the cleavage of ester intra-unit linkages within EGCG during pretreatment. Overall, our results suggest that apoplastic deposition of EGCG for incorporation into lignin would be a promising plant genetic engineering target for improving the delignification and saccharification of biomass crops. PMID:22889353

  4. Lignin phenols derivatives in lichens.

    PubMed

    Zavarzina, A G; Romankevich, E A; Peresypkin, V I; Ulyantzev, A S; Belyaev, N A; Zavarzin, A A

    2015-01-01

    Lignin monophenols have been measured in the cupric oxide oxidation products from lichens of different systematic groups. It is shown for the first time that syringyl structures in most lichens strongly dominate over vanillyl and p-hydroxyl ones (S/V 7-583, S/P 3-30). This distinguishes lichens from algae and mosses (p-hydroxyl phenols are dominant) and from higher plants (S/V ratios are from 0 in gymnosperms to 1.1-5.2 in angiosperms). Molecular ratios of phenols as well as the ratios of acids to aldehydes in lichens were different from lignin of higher plants, suggesting contribution of non-lignin phenols in CuO oxidation products. The contents of syringyl and vanillyl phenols in some lichen species were comparable to non-woody tissues of higher plants. Results of the study suggest that lichens can be important source of aromatic structures in soils and hydrosphere, particularly in the regions were lichens are abundant. PMID:26728733

  5. Lignins of bioenergy crops: a review?

    PubMed

    Guragain, Yadhu N; Herrera, Alvaro I; Vadlani, Praveen V; Prakash, Om

    2015-01-01

    Lignin provides structural support, a mechanical barrier against microbial infestation and facilitates movement of water inside plant systems. It is the second most abundant natural polymer in the terrestrial environments and possesses unique routes for the production of bulk and specialty chemicals with aromatic/phenolic skeletons. The commercial applications of lignin are limited and it is often recognized for its negative impact on the biochemical conversion of lignocellulosic biomass to fuels and chemicals. Understanding of the structure of lignin monomers and their interactions among themselves, as well as with carbohydrate polymers in biomass, is vital for the development of innovative biomass deconstruction processes and thereby valorization of all biopolymers of lignocellulosic residues, including lignin. In this paper, we review the major energy crops and their lignin structure, as well as the recent developments in biomass lignin characterization, with special focus on 1D and 2D Nuclear Magnetic Resonance (NMR) techniques. PMID:25920245

  6. Lignin-degrading peroxidases of Phanerochaete chrysosporium.

    PubMed

    Cai, D; Tien, M

    1993-07-01

    Lignin and manganese peroxidases are secreted by the basidiomycete Phanerochaete chrysosporium during secondary metabolism. These enzymes play major roles in lignin degradation. The active site amino acid sequence of these lignin-degrading peroxidases is similar to that of horseradish peroxidase (HRP) and cytochrome c peroxidase (CcP). The mechanism by which they oxidize substrates also appears to be the similar. pH has a similar effect on lignin peroxidase compound I formation as on HRP or CcP; however, the pKa controlling compound I formation for lignin peroxidase appears to be much lower. Lignin-degrading peroxidases are able to catalyze the oxidation of substrates with high redox potential. This unique ability is consistent with a heme active site of low electron density, which is indicated by high redox potential. PMID:7763834

  7. Designer lignins: harnessing the plasticity of lignification.

    PubMed

    Mottiar, Yaseen; Vanholme, Ruben; Boerjan, Wout; Ralph, John; Mansfield, Shawn D

    2016-02-01

    Lignin is a complex polyphenolic constituent of plant secondary cell walls. Inspired largely by the recalcitrance of lignin to biomass processing, plant engineering efforts have routinely sought to alter lignin quantity, composition, and structure by exploiting the inherent plasticity of lignin biosynthesis. More recently, researchers are attempting to strategically design plants for increased degradability by incorporating monomers that lead to a lower degree of polymerisation, reduced hydrophobicity, fewer bonds to other cell wall constituents, or novel chemically labile linkages in the polymer backbone. In addition, the incorporation of value-added structures could help valorise lignin. Designer lignins may satisfy the biological requirement for lignification in plants while improving the overall efficiency of biomass utilisation. PMID:26775114

  8. Lignin-Derived Advanced Carbon Materials

    DOE PAGESBeta

    Chatterjee, Sabornie; Saito, Tomonori

    2015-11-16

    Lignin is a highly abundant source of renewable carbon that can be considered as a valuable sustainable source of biobased materials. By applying specific pretreatments and manufacturing methods, it has been found that lignin can be converted into a variety of value-added carbon materials. However, the physical and chemical heterogeneities of lignin complicate its use as a feedstock. Herein, we discuss the lignin manufacturing process, the effects of pretreatments and manufacturing methods on the properties of product lignin, and structure–property relationships in various applications of lignin-derived carbon materials, such as carbon fibers, carbon mats, activated carbons, carbon films, and templatedmore » carbon.« less

  9. Lignin Formation in Wheat Coleoptile Cell Walls

    PubMed Central

    Whitmore, F. W.

    1971-01-01

    Four growth-influencing compounds—hydroxyproline, 2,2′-dipyridyl, 2-chloroethylphosphonic acid, and indoleacetic acid—were used to examine the relationship between lignin formation and growth of wheat coleoptile sections. Hydroxyproline and 2-chloroethylphosphonic acid, at low concentrations, inhibited growth and increased lignin content. Dipyridyl, which promoted coleoptile elongation, decreased lignin content. Indoleacetic acid caused a 300% increase in growth at 0.1 mm but resulted in lignin content no different from controls with no auxin. Chemical and anatomical evidence is given which indicates that lignin is present in the epidermal cell walls of the wheat coleoptile. It is thus possible that bonding between lignin and hemicellulose may have some influence on coleoptile growth. Images PMID:16657843

  10. The effects of acid precipitation runoff episodes on reservoir and tapwater quality in an Appalachian Mountain water supply.

    PubMed Central

    Sharpe, W E; DeWalle, D R

    1990-01-01

    The aluminum concentration and Ryznar Index increased and the pH decreased in a small Appalachian water supply reservoir following acid precipitation runoff episodes. Concomitant increases in tapwater aluminum and decreases in tapwater pH were also observed at two homes in the water distribution system. Lead concentrations in the tapwater of one home frequently exceeded recommended levels, although spatial and temporal variation in tapwater copper and lead concentrations was considerable. Since source water and reservoir water copper and lead concentrations were much lower, the increased copper and lead concentrations in tapwater were attributed to corrosion of household plumbing. Tapwater copper concentration correlated well with tapwater pH and tapwater temperature. Asbestos fibers were not detected in tapwater. The asbestos-cement pipe in the water distribution system was protected by a spontaneous metallic coating that inhibited fiber release from the pipe. Several simultaneous reactions were hypothesized to be taking place in the distribution system that involved corrosion of metallic components and coating of asbestos-cement pipe components in part with corrosion products and in part by cations of watershed origin. Greater water quality changes might be expected in areas of higher atmospheric deposition. Images FIGURE 5. FIGURE 6. PMID:2088742

  11. Cytocompatible cellulose hydrogels containing trace lignin.

    PubMed

    Nakasone, Kazuki; Kobayashi, Takaomi

    2016-07-01

    Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43N/mm(2) and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference. PMID:27127053

  12. EFFECTS OF ACID PRECIPITATION

    EPA Science Inventory

    Recent reviews of available data indicate that precipitation in a large region of North America is highly acidic when its pH is compared with the expected pH value of 5.65 for pure rain water in equilibrium with CO2. A growing body of evidence suggests that acid rain is responsib...

  13. Editorial: Acid precipitation

    SciTech Connect

    1995-09-01

    This editorial focuses on acid rain and the history of public and governmental response to acid rain. Comments on a book by Gwineth Howell `Acid Rain and Acid Waters` are included. The editor feels that Howells has provide a service to the environmental scientific community, with a textbook useful to a range of people, as well as a call for decision makers to learn from the acid rain issue and use it as a model for more sweeping global environmental issues. A balance is needed among several parameters such as level of evidence, probability that the evidence will lead to a specific direction and the cost to the global community. 1 tab.

  14. Method for recovering and using lignin in adhesive resins by extracting demethylated lignin

    DOEpatents

    Schroeder, Herbert A.

    1991-01-01

    Lignin, or a lignin derived material, which has been significantly demethylated (e.g., the demethylated lignin found in the raffinate produced as a by-product of dimethyl sulfide production which can be carried out using the spent liquor from wood pulping operations) can be isolated by a process wherein an organic solvent is added to a lignin-containing aqueous solution. The organic solvent is typically a polar, and at least a partially water-immiscible substance such as, for example, ethyl acetate. The resulting lignin-containing aqueous solution/organic solvent mixture is acidified to produce a water layer which is discarded and an organic solvent layer which contains the demethylated lignin. Upon its recovery, the demethylated lignin is preferably dried and stored until it is used (along with an alkali, an aldehyde and an adhesive filler) in compounding an adhesive of the type generally used in the manufacture of plywood.

  15. Identification of 4-O-5-Units in Softwood Lignins via Definitive Lignin Models and NMR.

    PubMed

    Yue, Fengxia; Lu, Fachuang; Ralph, Sally; Ralph, John

    2016-06-13

    Lignins are complex and heterogeneous natural polymers in which the major units are characterized by certain prominent interunit linkages. Previous attempts to identify and quantify 4-O-5-linked units in softwood lignins by NMR were not successful. In this work, various lignin model compounds, including the tetramers formed by the 4-O-5-coupling of β-O-4-, β-β-, and β-5-model dimers, were synthesized. Such compounds are better able to model the corresponding structures in lignins than those used previously. 4-O-5-Linked structures could be clearly observed and identified in real softwood lignin samples by comparison of their 2D HSQC NMR spectra with those from the model compounds. When comparing NMR data of phenol-acetylated versus phenol-etherified model compounds with those of acetylated lignins, it was apparent that most of the 4-O-5-linked structures in softwood lignins are present as free-phenolic end units. PMID:27078826

  16. Method for recovering and using lignin in adhesive resins by extracting demethylated lignin

    DOEpatents

    Schroeder, Herbert A.

    1991-01-01

    Lignin, or a lignin derived material, which has been significantly demethylated (e.g., the demethylated lignin found in the raffinate produced as a by-product of dimethyl sulfide production which can be carried out using the spent liquor from wood pulping operations) can be isolated by a process wherein an organic solvent is added to a lignin-containing aqueous solution. The organic solvent is typically a polar, and at least a partially water-immiscible substance such as, for example, ethyl acetate. The resulting lignin-containing aqueous solution/organic solvent mixture is acidified to produce a water layer which is discarded and an organic solvent layer which contains the demethylated lignin. Upon its recovery, the demethylated lignin is dissolved in an alkaline solution to which an aldehyde source is added to produce a resol-type resin. The aldehyde source may be formaldehyde in solution, paraformaldehyde, hexamethylenetetramine, or other aldehydes including acetaldehyde, furfural, and their derivatives.

  17. Effect of Penicillium chrysogenum on Lignin Transformation

    PubMed Central

    Rodríguez, A.; Carnicero, A.; Perestelo, F.; de la Fuente, G.; Milstein, O.; Falcón, M. A.

    1994-01-01

    A strain of Penicillium chrysogenum has been isolated from pine forest soils in Tenerife (Canary Islands). This strain was capable of utilizing hydroxylated and nonhydroxylated aromatic compounds, in particular cinnamic acid, as its sole carbon source. In an optimum medium with high levels of nitrogen (25.6 mM) and low levels of glucose (5.5 mM), it was able to decolorize Poly B-411 and to transform kraft, organosolv, and synthetic dehydrogenative polymerisate lignins. After 30 days of incubation, the amount of recovered kraft lignin was reduced to 83.5 and 91.3% of that estimated for uninoculated controls by spectrophotometry and klason lignin, respectively. At the same time, the pattern of molecular mass distribution of the lignin remaining in cultures was changed. The amount of organosolv lignin recovered from cultures was reduced to 90.1 and 94.6% of the initial amount as evaluated by spectrophotometry and klason lignin, respectively. About 6% of total applied radioactivity of O14CH3-organosolv lignin was recovered as 14CO2 after 30 days of incubation, and 18.5% of radioactivity from insoluble O14CH3-organosolv lignin was solubilized. After 26 days of incubation, 2.9% of 14C-β-dehydrogenative polymerisate and 4.1% of 14C-ring-dehydrogenative polymerisate evolved as 14CO2. PMID:16349361

  18. Development of Lignin-Based Polyurethane Thermoplastics

    SciTech Connect

    Saito, Tomonori; Perkins, Joshua H; Jackson, Daniel C; Trammell, Neil E; Hunt, Marcus A; Naskar, Amit K

    2013-01-01

    In our continued effort to develop value-added thermoplastics from lignin, here we report utilizing a tailored feedstock to synthesize mechanically robust thermoplastic polyurethanes at very high lignin contents (75 65 wt %). The molecular weight and glass transition temperature (Tg) of lignin were altered through cross-linking with formaldehyde. The cross-linked lignin was coupled with diisocyanate-based telechelic polybutadiene as a network-forming soft segment. The appearance of two Tg s, around 35 and 154 C, for the polyurethanes indicates the existence of two-phase morphology, a characteristic of thermoplastic copolymers. A calculated Flory-Huggins interaction parameter of 7.71 also suggests phase immiscibility in the synthesized lignin polyurethanes. An increase in lignin loading increased the modulus, and an increase in crosslink-density increased the modulus in the rubbery plateau region of the thermoplastic. This path for synthesis of novel lignin-based polyurethane thermoplastics provides a design tool for high performance lignin-based biopolymers.

  19. Lignin: Characterization of a Multifaceted Crop Component

    PubMed Central

    2013-01-01

    Lignin is a plant component with important implications for various agricultural disciplines. It confers rigidity to cell walls, and is therefore associated with tolerance to abiotic and biotic stresses and the mechanical stability of plants. In animal nutrition, lignin is considered an antinutritive component of forages as it cannot be readily fermented by rumen microbes. In terms of energy yield from biomass, the role of lignin depends on the conversion process. It contains more gross energy than other cell wall components and therefore confers enhanced heat value in thermochemical processes such as direct combustion. Conversely, it negatively affects biological energy conversion processes such as bioethanol or biogas production, as it inhibits microbial fermentation of the cell wall. Lignin from crop residues plays an important role in the soil organic carbon cycling, as it constitutes a recalcitrant carbon pool affecting nutrient mineralization and carbon sequestration. Due to the significance of lignin in several agricultural disciplines, the modification of lignin content and composition by breeding is becoming increasingly important. Both mapping of quantitative trait loci and transgenic approaches have been adopted to modify lignin in crops. However, breeding goals must be defined considering the conflicting role of lignin in different agricultural disciplines. PMID:24348159

  20. (Characterization of lignin peroxidases from Phanerochaete)

    SciTech Connect

    Not Available

    1990-11-14

    Work has continued on characterizing the kinetics of lignin peroxidases and has now expanded to include the chemistry of Mn peroxidases. Progress in these two area in addition to the authors work on the molecular biology of lignin biodegradation is briefly described below. Copies of two reprints and one preprint which have resulted from the work are attached.

  1. Method for regulation of plant lignin composition

    DOEpatents

    Chapple, Clint

    1999-01-01

    A method is disclosed for the regulation of lignin composition in plant tissue. Plants are transformed with a gene encoding an active F5H gene. The expression of the F5H gene results in increased levels of syringyl monomer providing a lignin composition more easily degraded with chemicals and enzymes.

  2. Biodegradation of lignin by Agaricus Bisporus

    SciTech Connect

    Vane, C.H.; Abbott, G.D.; Head, I.M.

    1996-12-31

    The lignolytic activity of Agaricus bisporus will be addressed in this paper. Sound and fungally degraded lignins were characterized by Pyrolysis-Gas Chromatography-Mass Spectrometry (Py-GC-MS), Fourier Transform Infrared Spectroscopy (FnR) and elemental analysis. Fungally degraded lignins displayed increased wt%N, wt%H and wt%O content and decreased wt%C content The FTIR spectrum of decayed lignin showed an increase in the relative intensity of absorption bands assigned to carbonyl and carboxyl functional groups located on the aliphatic side chain and a decrease in absorption bands assigned to aromatic skeletal vibration modes. Semiquantitative Py-GC-MS revealed an 82% decrease in lignin derived pyrolysis products upon biodegradation. No significant increase in pyrolysis products with an oxygenated aliphatic side chain were detected in the fungally degraded lignin however shortening of the aliphatic side chain via cleavage at the {alpha}, {beta} and {gamma} positions was observed.

  3. Enzymatic conversion of lignin into renewable chemicals.

    PubMed

    Bugg, Timothy D H; Rahmanpour, Rahman

    2015-12-01

    The aromatic heteropolymer lignin is a major component of plant cell walls, and is produced industrially from paper/pulp manufacture and cellulosic bioethanol production. Conversion of lignin into renewable chemicals is a major unsolved problem in the development of a biomass-based biorefinery. The review describes recent developments in the understanding of bacterial enzymes for lignin breakdown, such as DyP peroxidases, bacterial laccases, and beta-etherase enzymes. The use of pathway engineering methods to construct genetically modified microbes to convert lignin to renewable chemicals (e.g. vanillin, adipic acid) via fermentation is discussed, and the search for novel applications for lignin (e.g. carbon fibre). PMID:26121945

  4. Functionalization of lignin through ATRP grafting of poly(2-dimethylaminoethyl methacrylate) for gene delivery.

    PubMed

    Liu, Xiaohong; Yin, Hui; Zhang, Zhongxing; Diao, Bishuo; Li, Jun

    2015-01-01

    The biomass kraft lignin was modified into lignin-based macroinitiators (LnMI) through esterification of the alcohol and phenol functional groups on lignin backbone with 2-bromo-isobutyric bromide under mild condition. Then a series of cationic amphiphilic lignin-based graft copolymers were synthesized by atom transfer radical polymerization (ATRP) of 2-(dimethylamino)ethyl methacrylate (DMAEMA) starting from the lignin-based macroinitiators. These copolymers, denoted as LnPDMAEMA, had a hyperbranched structure with a hydrophobic backbone of lignin and multiple cationic hydrophilic arms of PDMAEMA. The LnPDMAEMA copolymers were characterized by (1)H NMR and elemental analysis (EA), and studied in terms of their DNA binding capability, formation of nanoparticles with plasmid DNA (pDNA), cytotoxicity, and gene transfection in cultured cells. It was found that all the copolymers could efficiently compact pDNA into nanoparticles with sizes ranging from 100 to 200 nm at N/P ratios of 5 or higher. The cytotoxicity of these copolymers depends greatly on the chain length of PDMAEMA arms, the longer the PAMAEMA chain the higher the cytotoxicity. Luciferase assay was used to study the in vitro gene transfection for the LnPDMAEMA copolymers in different cell lines. The gene transfection efficiency of these copolymers was dependent on the grafted PDMAEMA chain length and N/P ratio. Generally, the transfection efficiency decreased with the increase of PAMAEMA length at N/P ratio of 20 or higher. It is very interesting that one of the LnPDMAEMA copolymers with very short arm length (degree of average DMAEMA units=5.5) showed excellent in vitro transfection efficiency that was comparable or even higher than that of branched PEI (25K). These novel biomass-based LnPDMAEMA hyperbranched copolymers can be a promising nonviral gene vectors for future gene delivery application. PMID:25506805

  5. Chain Reaction Polymerization.

    ERIC Educational Resources Information Center

    McGrath, James E.

    1981-01-01

    The salient features and importance of chain-reaction polymerization are discussed, including such topics as the thermodynamics of polymerization, free-radical polymerization kinetics, radical polymerization processes, copolymers, and free-radical chain, anionic, cationic, coordination, and ring-opening polymerizations. (JN)

  6. Methanol Fractionation of Softwood Kraft Lignin: Impact on the Lignin Properties

    SciTech Connect

    Saito, Tomonori; Perkins, Joshua H; Vautard, Frederic; Meyer III, Harry M; Messman, Jamie M; Tolnai, Balazs; Naskar, Amit K

    2014-01-01

    The development of technologies to tune lignin properties for high-performance lignin-based materials is crucial for the utilization of lignin in various applications. Here, the effect of methanol (MeOH) fractionation on the molecular weight, molecular weight distribution, glass transition temperature (Tg), thermal decomposition, and chemical structure of lignin were investigated. Repeated MeOH fractionation of softwood Kraft lignin successfully removed the low-molecular-weight fraction. The separated high-molecular-weight lignin showed a Tg of 211 C and a char yield of 47%, much higher than those of asreceived lignin (Tg 153 C, char yield 41%). The MeOH-soluble fraction of lignin showed an increased low-molecular-weight fraction and a lower Tg (117 C) and char yield (32%). The amount of low-molecular-weight fraction showed a quantitative correlation with both 1/Tg and char yield in a linear regression. This study demonstrated the efficient purification or fractionation technology for lignin; it also established a theoretical and empirical correlation between the physical characteristics of fractionated lignins.

  7. Genetic Augmentation of Syringyl Lignin in Low-lignin Aspen Trees, Final Report

    SciTech Connect

    Chung-Jui Tsai; Mark F. Davis; Vincent L. Chiang

    2004-11-10

    As a polysaccharide-encrusting component, lignin is critical to cell wall integrity and plant growth but also hinders recovery of cellulose fibers during the wood pulping process. To improve pulping efficiency, it is highly desirable to genetically modify lignin content and/or structure in pulpwood species to maximize pulp yields with minimal energy consumption and environmental impact. This project aimed to genetically augment the syringyl-to-guaiacyl lignin ratio in low-lignin transgenic aspen in order to produce trees with reduced lignin content, more reactive lignin structures and increased cellulose content. Transgenic aspen trees with reduced lignin content have already been achieved, prior to the start of this project, by antisense downregulation of a 4-coumarate:coenzyme A ligase gene (Hu et al., 1999 Nature Biotechnol 17: 808- 812). The primary objective of this study was to genetically augment syringyl lignin biosynthesis in these low-lignin trees in order to enhance lignin reactivity during chemical pulping. To accomplish this, both aspen and sweetgum genes encoding coniferaldehyde 5-hydroxylase (Osakabe et al., 1999 PNAS 96: 8955-8960) were targeted for over-expression in wildtype or low-lignin aspen under control of either a constitutive or a xylem-specific promoter. A second objective for this project was to develop reliable and cost-effective methods, such as pyrolysis Molecular Beam Mass Spectrometry and NMR, for rapid evaluation of cell wall chemical components of transgenic wood samples. With these high-throughput techniques, we observed increased syringyl-to-guaiacyl lignin ratios in the transgenic wood samples, regardless of the promoter used or gene origin. Our results confirmed that the coniferaldehyde 5-hydroxylase gene is key to syringyl lignin biosynthesis. The outcomes of this research should be readily applicable to other pulpwood species, and promise to bring direct economic and environmental benefits to the pulp and paper industry.

  8. Characterization of electrospun lignin based carbon fibers

    NASA Astrophysics Data System (ADS)

    Poursorkhabi, Vida; Mohanty, Amar; Misra, Manjusri

    2015-05-01

    The production of lignin fibers has been studied in order to replace the need for petroleum based precursors for carbon fiber production. In addition to its positive environmental effects, it also benefits the economics of the industries which cannot take advantage of carbon fiber properties because of their high price. A large amount of lignin is annually produced as the byproduct of paper and growing cellulosic ethanol industry. Therefore, finding high value applications for this low cost, highly available material is getting more attention. Lignin is a biopolymer making about 15 - 30 % of the plant cell walls and has a high carbon yield upon carbonization. However, its processing is challenging due to its low molecular weight and also variations based on its origin and the method of separation from cellulose. In this study, alkali solutions of organosolv lignin with less than 1 wt/v% of poly (ethylene oxide) and two types of lignin (hardwood and softwood) were electrospun followed by carbonization. Different heating programs for carbonization were tested. The carbonized fibers had a smooth surface with an average diameter of less than 5 µm and the diameter could be controlled by the carbonization process and lignin type. Scanning electron microscopy (SEM) was used to study morphology of the fibers before and after carbonization. Thermal conductivity of a sample with amorphous carbon was 2.31 W/m.K. The electrospun lignin carbon fibers potentially have a large range of application such as in energy storage devices and water or gas purification systems.

  9. Characterization of asparagus lignin by HPLC.

    PubMed

    Jaramillo-Carmona, S; Fuentes-Alventosa, J M; Rodríguez-Gutiérrez, G; Waldron, K W; Smith, A C; Guillén-Bejarano, R; Fernández-Bolaños, J; Jiménez-Araujo, A; Rodríguez-Arcos, R

    2008-09-01

    Lignin is the cell wall component most frequently associated with hardening. Its characterization and quantification are very important to understand the biochemical modifications related to the changes in texture of vegetables such as asparagus (Asparagus officinalis), in which this organoleptic attribute is a very important quality factor. In this study, asparagus lignin from the basal sections of fresh and stored spears was analyzed using 2 methods, the traditional (Klason lignin) and the recently developed derivatization, followed by reductive cleavage (DFRC) method. The latter is a simple and reproducible technique for lignin characterization based on a degradation procedure that produces analyzable monomers and dimers by cleaving alpha- and beta-aryl ethers in lignins. The primary monomers derived from DFRC degradation of lignins are essentially p-coumaryl peracetate, coniferyl peracetate, and sinapyl peracetate. To evaluate the efficiency of the DFRC method, our investigations have been carried on distinct sample types, including wood (data not shown), straw, and asparagus samples. The results have confirmed that lignin composition is affected by plant nature. It has been found that whereas wood samples mostly contain coniferyl units, plant foods, such as straw and asparagus, contain both coniferyl and guaiacyl units. PMID:18803697

  10. Lignin-derived phenols in Houston aerosols: implications for natural background sources.

    PubMed

    Shakya, Kabindra M; Louchouarn, Patrick; Griffin, Robert J

    2011-10-01

    Solvent-extractable monomeric methoxyphenols in aerosol samples conventionally have been used to indicate the influence of biomass combustion. In addition, the presence of lignin oxidation products (LOP), derived from the CuO oxidation of vascular plant organic matter, can help trace the source and inputs of primary biological particles in aerosols. Ambient aerosols (coarse and fine) collected in Houston during summer 2010 were analyzed by gas chromatography-mass spectrometry to characterize monomeric and polymeric sources of LOPs. This is the first time polymeric forms of the LOPs have been characterized in ambient aerosols. The absence or small concentrations of solvent-extractable monomeric LOPs and levoglucosan isomers point to the limited influence of biomass burning during the sampling period. The trace levels of anhydrosugar concentrations most likely result from long-range transport. This observation is supported by the absence of co-occurring lignin monomers that undergo photochemical degradation during transport. The larger concentration (142 ng m(-3)) of lignin polymers in coarse aerosols shows the relative importance of primary biological aerosol particles, even in the urban atmosphere. The LOP parameters suggest a predominant influence from woody tissue of angiosperms, with minor influence from soft tissues, gymnosperms, and soil organic matter. PMID:21877739

  11. Regiochemical control of monolignol radical coupling: a new paradigm for lignin and lignan biosynthesis

    NASA Technical Reports Server (NTRS)

    Gang, D. R.; Costa, M. A.; Fujita, M.; Dinkova-Kostova, A. T.; Wang, H. B.; Burlat, V.; Martin, W.; Sarkanen, S.; Davin, L. B.; Lewis, N. G.

    1999-01-01

    BACKGROUND: Although the lignins and lignans, both monolignol-derived coupling products, account for nearly 30% of the organic carbon circulating in the biosphere, the biosynthetic mechanism of their formation has been poorly understood. The prevailing view has been that lignins and lignans are produced by random free-radical polymerization and coupling, respectively. This view is challenged, mechanistically, by the recent discovery of dirigent proteins that precisely determine both the regiochemical and stereoselective outcome of monolignol radical coupling. RESULTS: To understand further the regulation and control of monolignol coupling, leading to both lignan and lignin formation, we sought to clone the first genes encoding dirigent proteins from several species. The encoding genes, described here, have no sequence homology with any other protein of known function. When expressed in a heterologous system, the recombinant protein was able to confer strict regiochemical and stereochemical control on monolignol free-radical coupling. The expression in plants of dirigent proteins and proposed dirigent protein arrays in developing xylem and in other lignified tissues indicates roles for these proteins in both lignan formation and lignification. CONCLUSIONS: The first understanding of regiochemical and stereochemical control of monolignol coupling in lignan biosynthesis has been established via the participation of a new class of dirigent proteins. Immunological studies have also implicated the involvement of potential corresponding arrays of dirigent protein sites in controlling lignin biopolymer assembly.

  12. Non-extractable procyanidins and lignin are important factors in the bile acid binding and radical scavenging properties of cell wall material in some fruits.

    PubMed

    Hamauzu, Yasunori; Mizuno, Yukari

    2011-03-01

    The cell wall components and the food functions of alcohol-insoluble solids (AIS) of Chinese quince, quince, hawthorn, apple, pear and blueberry fruits were analyzed. Chinese quince contained characteristically high contents of cellulose, lignin, and non-extractable procyanidins (NEPCs). On the other hand, the quince AIS contained the highest proportion of NEPCs, the highest mean degree of polymerization (mDP), the strongest radical scavenging activity, and strong bile acid binding activity. In fruit AIS, the lignin and NEPC contents both showed positive correlations with the bile acid binding and radical scavenging activities. The value for mDP × NEPC content was a good index for the radical scavenging activity. The results suggest that highly polymerized NEPCs and lignin are important factors of cell wall components of fruits to having a high functionality, and Chinese quince and quince are interesting fruits from this view point. PMID:21243435

  13. Effects of Soluble Lignin on the Formic Acid-Catalyzed Formation of Furfural: A Case Study for the Upgrading of Hemicellulose.

    PubMed

    Dussan, Karla; Girisuta, Buana; Lopes, Marystela; Leahy, James J; Hayes, Michael H B

    2016-03-01

    A comprehensive study is presented on the conversion of hemicellulose sugars in liquors obtained from the fractionation of Miscanthus, spruce bark, sawdust, and hemp by using formic acid. Experimental tests with varying temperature (130-170 °C), formic acid concentration (10-80 wt%), carbohydrate concentrations, and lignin separation were carried out, and experimental data were compared with predictions obtained by reaction kinetics developed in a previous study. The conversions of xylose and arabinose into furfural were inherently affected by the presence of polymeric soluble lignin, decreasing the maximum furfural yields observed experimentally by up to 24%. These results were also confirmed in synthetic mixtures of pentoses with Miscanthus and commercial alkali lignin. This observation was attributed to side reactions involving intermediate stable sugar species reacting with solubilized lignin during the conversion of xylose into furfural. PMID:26805656

  14. A molecular mechanics force field for lignin

    SciTech Connect

    Petridis, Loukas; Smith, Jeremy C

    2009-02-01

    A CHARMM molecular mechanics force field for lignin is derived. Parameterization is based on reproducing quantum mechanical data of model compounds. Partial atomic charges are derived using the RESP electrostatic potential fitting method supplemented by the examination of methoxybenzene:water interactions. Dihedral parameters are optimized by fitting to critical rotational potentials and bonded parameters are obtained by optimizing vibrational frequencies and normal modes. Finally, the force field is validated by performing a molecular dynamics simulation of a crystal of a lignin fragment molecule and comparing simulation-derived structural features with experimental results. Together with the existing force field for polysaccharides, this lignin force field will enable full simulations of lignocellulose.

  15. Lignin Sensor Based On Flash-Pyrolysis Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Kwack, Eug Y.; Lawson, Daniel D.; Shakkottai, Parthasarathy

    1990-01-01

    New lignin sensor takes only few minutes to measure lignin content of specimen of wood, pulp, paper, or similar material. Includes flash pyrolizer and ion-trap detector that acts as mass spectrometer. Apparatus measures amount of molecular fragments of lignin in pyrolysis products of samples. Helpful in controlling digestors in paper mills to maintain required lignin content, and also in bleaching plants, where good control of bleaching becomes possible if quick determination of lignin content made.

  16. Computational Design of Lignin Depolymerization Catalysts

    SciTech Connect

    Kim, S.; Chmely, S. C.; Sturgeon, M.; Katahira, R.; Paton, R. S.; Beckham, G. T.

    2012-01-01

    Lignin is a major component of plant cell walls that is typically underutilized in selective conversion strategies for renewable fuels and chemicals. The mechanisms by which thermal and catalytic treatments deconstruct lignin remain elusive, for which quantum mechanical calculations can offer fundamental insights. In this work, a computational approach has been used to elucidate the reductive deconstruction pathway of a ruthenium-catalyzed system. Transition states have been computed to determine the rate-limiting steps for a catalyst that cleaves arylether linkages. Our calculations are supported by experimental synthesis and kinetic and thermodynamic measurements of the deconstruction of model lignin dimers by a ruthenium catalyst with the ultimate objective of designing new catalysts to eventually utilize lignin in biorefineries.

  17. In vitro evaluation of the mixed xanthan/lignin hydrogels as vanillin carriers

    NASA Astrophysics Data System (ADS)

    Raschip, Irina Elena; Hitruc, Elena Gabriela; Oprea, Ana Maria; Popescu, Maria-Cristina; Vasile, Cornelia

    2011-09-01

    Various amounts of lignin from annual fiber crops (GL) exhibiting antioxidant properties were incorporated in xanthan to obtain hydrogel films. These mixed xanthan/lignin hydrogels were evaluated as matrices for vanillin release as active aroma ingredient. The new obtained biodegradable polymeric matrices, containing vanillin, have been characterized by the swelling/release experiments, FT-IR and AFM analysis. As a novelty, AFM microscopy was done on powder form. In FT-IR spectra after incorporation of the aroma, the shifting of the bands at 1618 and 1510 cm -1 (assigned to C dbnd C stretching vibration) to higher wavenumbers was observed, indicating interactions between components. The comparison of all the results afforded by the various characterization methods leads to the conclusion that the 70X/30GL hydrogel (15% within 100 min) slower releases the vanillin aroma more than 90X/10GL (18% within 100 min) one because of stronger inter- and intramolecular interactions between matrix and active substance.

  18. Production of manganic chelates by laccase from the lignin-degrading fungus Trametes (Coriolus) versicolor.

    PubMed Central

    Archibald, F; Roy, B

    1992-01-01

    Many ligninolytic basidiomycete fungi have been shown to secrete a group of peroxidase isozymes whose sole function appears to be the peroxide-dependent oxidation of manganous [Mn(II)] to manganic [Mn(III)] ions. Manganic chelates and these Mn peroxidases have been implicated as central to the degradation of various natural and synthetic lignins and lignin-containing effluents by white rot (ligninolytic) fungi. Another group of enzymes, the laccases, are commonly secreted by wood-rotting fungi, but are generally regarded as being able to oxidize (and usually polymerize) only phenolic substrates. In this report it is shown that in the presence of appropriate oxidizable phenolic accessory substances or primary substrates, a variety of laccases and peroxidases catalyzing one-electron oxidations can also produce Mn(III) chelates from Mn(II). PMID:1622216

  19. Metagenomic scaffolds enable combinatorial lignin transformation

    PubMed Central

    Strachan, Cameron R.; Singh, Rahul; VanInsberghe, David; Ievdokymenko, Kateryna; Budwill, Karen; Mohn, William W.; Eltis, Lindsay D.; Hallam, Steven J.

    2014-01-01

    Engineering the microbial transformation of lignocellulosic biomass is essential to developing modern biorefining processes that alleviate reliance on petroleum-derived energy and chemicals. Many current bioprocess streams depend on the genetic tractability of Escherichia coli with a primary emphasis on engineering cellulose/hemicellulose catabolism, small molecule production, and resistance to product inhibition. Conversely, bioprocess streams for lignin transformation remain embryonic, with relatively few environmental strains or enzymes implicated. Here we develop a biosensor responsive to monoaromatic lignin transformation products compatible with functional screening in E. coli. We use this biosensor to retrieve metagenomic scaffolds sourced from coal bed bacterial communities conferring an array of lignin transformation phenotypes that synergize in combination. Transposon mutagenesis and comparative sequence analysis of active clones identified genes encoding six functional classes mediating lignin transformation phenotypes that appear to be rearrayed in nature via horizontal gene transfer. Lignin transformation activity was then demonstrated for one of the predicted gene products encoding a multicopper oxidase to validate the screen. These results illuminate cellular and community-wide networks acting on aromatic polymers and expand the toolkit for engineering recombinant lignin transformation based on ecological design principles. PMID:24982175

  20. Top Value-Added Chemicals from Biomass - Volume II—Results of Screening for Potential Candidates from Biorefinery Lignin

    SciTech Connect

    Holladay, John E.; White, James F.; Bozell, Joseph J.; Johnson, David

    2007-10-01

    This report evaluates lignin’s role as a renewable raw material resource. Opportunities that arise from utilizing lignin fit into one of three categories: 1)power, fuel and syngas (generally near-term opportunities) 2) macromolecules (generally medium-term opportunities) 3) aromatics and miscellaneous monomers (long-term opportunities). Biorefineries will receive and process massive amounts of lignin. For this reason, how lignin can be best used to support the economic health of the biorefinery must be defined. An approach that only considers process heat would be shortsighted. Higher value products present economic opportunities and the potential to significantly increase the amount of liquid transportation fuel available from biomass. In this analysis a list of potential uses of lignin was compiled and sorted into “product types” which are broad classifications (listed above as power—fuel—syngas; macromolecules; and aromatics). In the first “product type” (power—fuel—gasification) lignin is used purely as a carbon source and aggressive means are employed to break down its polymeric structure. In the second “product type” (macromolecules) the opposite extreme is considered and advantage of the macromolecular structure imparted by nature is retained in high-molecular weight applications. The third “product type” (aromatics) lies somewhere between the two extremes and employs technologies that would break up lignin’s macromolecular structure but maintain the aromatic nature of the building block molecules. The individual opportunities were evaluated based on their technical difficulty, market, market risk, building block utility, and whether a pure material or a mixture would be produced. Unlike the “Sugars Top 10” report it was difficult to identify the ten best opportunities, however, the potential opportunities fell nicely into near-, medium- and long-term opportunities. Furthermore, the near-, medium- and long-term opportunities

  1. Recovering ultraclean lignins of controlled molecular weight from Kraft black-liquor lignins.

    PubMed

    Klett, A S; Chappell, P V; Thies, M C

    2015-08-18

    By operating in a region of liquid-liquid equilibrium, hot acetic acid-water mixtures can be used to simultaneously clean, fractionate, and solvate Kraft black-liquor lignins. Lignin-rich liquid phases of controlled molecular weight with key metals contents reduced to <50 ppm are obtained without a washing step. PMID:26169767

  2. Characterization of electrospun lignin based carbon fibers

    SciTech Connect

    Poursorkhabi, Vida; Mohanty, Amar; Misra, Manjusri

    2015-05-22

    The production of lignin fibers has been studied in order to replace the need for petroleum based precursors for carbon fiber production. In addition to its positive environmental effects, it also benefits the economics of the industries which cannot take advantage of carbon fiber properties because of their high price. A large amount of lignin is annually produced as the byproduct of paper and growing cellulosic ethanol industry. Therefore, finding high value applications for this low cost, highly available material is getting more attention. Lignin is a biopolymer making about 15 – 30 % of the plant cell walls and has a high carbon yield upon carbonization. However, its processing is challenging due to its low molecular weight and also variations based on its origin and the method of separation from cellulose. In this study, alkali solutions of organosolv lignin with less than 1 wt/v% of poly (ethylene oxide) and two types of lignin (hardwood and softwood) were electrospun followed by carbonization. Different heating programs for carbonization were tested. The carbonized fibers had a smooth surface with an average diameter of less than 5 µm and the diameter could be controlled by the carbonization process and lignin type. Scanning electron microscopy (SEM) was used to study morphology of the fibers before and after carbonization. Thermal conductivity of a sample with amorphous carbon was 2.31 W/m.K. The electrospun lignin carbon fibers potentially have a large range of application such as in energy storage devices and water or gas purification systems.

  3. Incorporation of Epicatechin Esters into Lignin Enhances Cell Wall Fermentability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyphenolic catechin esters are potentially attractive targets for lignin bioengineering because their copolymerization with monolignols could reduce lignin hydrophobicity and cross-linking to polysaccharides, or facilitate delignification by biomass pretreatments. To test this hypothesis, we biomi...

  4. Over-expression of F5H in COMT-deficient Arabidopsis leads to enrichment of an unusual lignin and disruption of pollen wall formation.

    PubMed

    Weng, Jing-Ke; Mo, Huaping; Chapple, Clint

    2010-12-01

    The presence of the phenylpropanoid polymer lignin in plant cell walls impedes breakdown of polysaccharides to the fermentable sugars that are used in biofuel production. Genetically modified plants with altered lignin properties hold great promise to improve biomass degradability. Here, we describe the generation of a new type of lignin enriched in 5-hydroxy-guaiacyl units by over-expressing ferulate 5-hydroxylase in a line of Arabidopsis lacking caffeic acid O-methyltransferase. The lignin modification strategy had a profound impact on plant growth and development and cell-wall properties, and resulted in male sterility due to complete disruption of formation of the pollen wall. The modified plants showed significantly improved cell-wall enzymatic saccharification efficiency without a reduction in post-harvest biomass yield despite the alterations in the overall growth morphology. This study demonstrated the plasticity of lignin polymerization in terms of incorporation of unusual monomers that chemically resemble conventional monomers, and also revealed the link between the biosynthetic pathways of lignin and the pollen wall-forming sporopollenin. PMID:21143672

  5. Isolation of functionalized phenolic monomers through selective oxidation and C-O bond cleavage of the β-O-4 linkages in lignin.

    PubMed

    Lancefield, Christopher S; Ojo, O Stephen; Tran, Fanny; Westwood, Nicholas J

    2015-01-01

    Functionalized phenolic monomers have been generated and isolated from an organosolv lignin through a two-step depolymerization process. Chemoselective catalytic oxidation of β-O-4 linkages promoted by the DDQ/tBuONO/O2 system was achieved in model compounds, including polymeric models and in real lignin. The oxidized β-O-4 linkages were then cleaved on reaction with zinc. Compared to many existing methods, this protocol, which can be achieved in one pot, is highly selective, giving rise to a simple mixture of products that can be readily purified to give pure compounds. The functionality present in these products makes them potentially valuable building blocks. PMID:25377996

  6. Deconstruction of Lignin Model Compounds and Biomass-Derived Lignin using Layered Double Hydroxide Catalysts

    SciTech Connect

    Chmely, S. C.; McKinney, K. A.; Lawrence, K. R.; Sturgeon, M.; Katahira, R.; Beckham, G. T.

    2013-01-01

    Lignin is an underutilized value stream in current biomass conversion technologies because there exist no economic and technically feasible routes for lignin depolymerization and upgrading. Base-catalyzed deconstruction (BCD) has been applied for lignin depolymerization (e.g., the Kraft process) in the pulp and paper industry for more than a century using aqueous-phase media. However, these efforts require treatment to neutralize the resulting streams, which adds significantly to the cost of lignin deconstruction. To circumvent the need for downstream treatment, here we report recent advances in the synthesis of layered double hydroxide and metal oxide catalysts to be applied to the BCD of lignin. These catalysts may prove more cost-effective than liquid-phase, non-recyclable base, and their use obviates downstream processing steps such as neutralization. Synthetic procedures for various transition-metal containing catalysts, detailed kinetics measurements using lignin model compounds, and results of the application of these catalysts to biomass-derived lignin will be presented.

  7. Polymeric materials from renewable resources

    NASA Astrophysics Data System (ADS)

    Frollini, Elisabete; Rodrigues, Bruno V. M.; da Silva, Cristina G.; Castro, Daniele O.; Ramires, Elaine C.; de Oliveira, Fernando; Santos, Rachel P. O.

    2016-05-01

    The goals of our studies have been the use of renewable raw materials in the preparation of polymeric materials with diversified properties. In this context, lignosulfonate, which is produced in large scale around the world, but not widely used in the production of polymeric materials, was used to replace phenol and polyols in the preparation of phenolic- (Ligno-PH) and polyurethane-type (Ligno-PU) polymers, respectively. These polymers were used to prepare composites reinforced with sisal lignocellulosic fibers. The use of lignosulfonate in the formulation of both types of polymers was beneficial, because in general composites with improved properties, specially impact strength, were obtained. Composites were also prepared from the so called "biopolyethylene" (HDPE), curaua lignocellulosic fiber, and castor oil (CO). All composites HDBPE/CO/Fiber exhibited higher impact strength, when compared to those of the corresponding HDBPE/Fiber. These results, combined with others (eg SEM images of the fractured surfaces) indicated that, in addition to acting as a plasticizer, this oil may have acted as a compatibilizer of the hydrophilic fiber with the hydrophobic polymer. The set of results indicated that (i) mats with nano (diameter ≤ 100nm) and/or ultrafine (submicron scale) fibers were produced, (ii) hybrid fibers were produced (bio-based mats composites), (iii) cellulosic pulp (CP) and/or lignin (Lig) can be combined with PET matrices to control properties such as stiffness and hydrophilicity of the respective mats. Materials with diversified properties were prepared from high content of renewable raw materials, thus fulfilling the proposed targets.

  8. Anaerobic biodegradation of the lignin and polysaccharide components of lignocellulose and synthetic lignin by sediment microflora

    SciTech Connect

    Benner, R.; Maccubbin, A.E.; Hodson, R.E.

    1984-05-01

    Specifically radiolabeled (/sup 14/C-lignin)lignocelluloses and (/sup 14/C-polysaccharide)lignocelluloses were prepared from a variety of marine and freshwater wetland plants including a grass, a sedge, a rush, and a hardwood. These (/sup 14/C)lignocellulose preparations and synthetic (/sup 14/C)lignin were incubated anaerobically with anoxic sediments collected from a salt marsh, a freshwater marsh, and a mangrove swamp. During long-term incubations lasting up to 300 days, the lignin and polysaccharide components of the lignocelluloses were slowly degraded anaerobically to /sup 14/CO/sub 2/ and /sup 14/CH/sub 4/. Lignocelluloses derived from herbaceous plants were degraded more rapidly than lignocellulose derived from the hardwood. After 294 days, 16.9% of the lignin component and 30.0% of the polysaccharide component of lignocellulose derived from the grass used (Spartina alterniflora) were degraded to gaseous end products. In contrast, after 246 days, only 1.5% of the lignin component and 4.1% of the polysaccharide component of lignocellulose derived from the hardwood used (Rhizophora mangle) were degraded to gaseous end products. Synthetic (/sup 14/C) lignin was degraded anaerobically faster than the lignin component of the hardwood lignocellulose; after 276 days 3.7% of the synthetic lignin was degraded to gaseous end products. Contrary to previous reports, these results demonstrate that lignin and lignified plant tissues are biodegradable in the absence of oxygen. Although lignocelluloses are recalcitrant to anaerobic biodegradation, rates of degradation measured in aquatic sediments are significant and have important implications for the biospheric cycling of carbon from these abundant biopolymers. 31 references.

  9. Fungal biodegradation and enzymatic modification of lignin

    PubMed Central

    Dashtban, Mehdi; Schraft, Heidi; Syed, Tarannum A.; Qin, Wensheng

    2010-01-01

    Lignin, the most abundant aromatic biopolymer on Earth, is extremely recalcitrant to degradation. By linking to both hemicellulose and cellulose, it creates a barrier to any solutions or enzymes and prevents the penetration of lignocellulolytic enzymes into the interior lignocellulosic structure. Some basidiomycetes white-rot fungi are able to degrade lignin efficiently using a combination of extracellular ligninolytic enzymes, organic acids, mediators and accessory enzymes. This review describes ligninolytic enzyme families produced by these fungi that are involved in wood decay processes, their molecular structures, biochemical properties and the mechanisms of action which render them attractive candidates in biotechnological applications. These enzymes include phenol oxidase (laccase) and heme peroxidases [lignin peroxidase (LiP), manganese peroxidase (MnP) and versatile peroxidase (VP)]. Accessory enzymes such as H2O2-generating oxidases and degradation mechanisms of plant cell-wall components in a non-enzymatic manner by production of free hydroxyl radicals (·OH) are also discussed. PMID:21968746

  10. Selective Conversion of Biorefinery Lignin into Dicarboxylic Acids

    SciTech Connect

    Ma, Ruoshui; Guo, Mond; Zhang, Xiao

    2014-02-01

    The emerging biomass-to-biofuel conversion industry has created an urgent need for identifying new applications for biorefinery lignin. This paper demonstrates a new route to producing dicarboxylic acids from biorefinery lignin through chalcopyrite-catalyzed oxidation in a highly selective process. Up to 95 % selectivity towards stable dicarboxylic acids was obtained for several types of biorefinery lignin and model compounds under mild, environmentally friendly reaction conditions. The findings from this study paved a new avenue to biorefinery lignin conversions and applications.

  11. Structure and radical scavenging activity relationships of pyrolytic lignins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This work deals with antioxidant properties of pyrolytic lignins against two free radicals, the 1,1-diphenyl-2-picrylhydrazyl and the 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid). Pyrolytic lignins produced by the thermal pyrolysis of the Etek lignin were extracted from the liquid pyrolysi...

  12. Genetics and chemistry of lignin degradation by Streptomyces

    SciTech Connect

    Crawford, D.L.

    1992-01-01

    Our research goal was to define the involvement of lignin peroxidases and other extracellular enzymes in lignin degradation by Streptomyces. We examined the biochemistry and genetics of lignin degrading enzyme production by several strains of Streptomyces. The lignin peroxidase ALiP-P3 of S. viridosporus was characterized kinetically and its activity optimized for oxidation of 2,4-dichlorophenol and vanillyl-acetone. Sensitive spectrophotometric assays were developed for monitoring oxidation of these substrates. ALiP-P3 reaction chemistry was examined using both spectrophotometric assays and gas chromatography/mass spectroscopy. Results showed that the enzyme oxidizes phenolic lignin substructure models in strong preference to nonphenolic ones. The peroxidase was also shown to depolymerize native lignin. We also cloned the ALip-P3 gene S. lividans in plasmid vector pIJ702. The cloned gene was partially sequenced, We also immunologically characterized the lignin peroxidase of S. viridosporus T7A and showed it to be structurally related to peroxidases produced by other lignin-solubilizing Streptomyces, but not the the H8 lignin peroxidase of P. chrysosporium. Studies with peroxidase deficient mutants of strain T7A showed that lignin peroxidases of S. viridosporus are directly involved in the solubilization of lignin. Additional research showed that other enzymes are also probably involved in lignin solubilization, possibly including extracellular esterases.

  13. Genetic engineering of syringyl-enriched lignin in plants

    DOEpatents

    Chiang, Vincent Lee; Li, Laigeng

    2004-11-02

    The present invention relates to a novel DNA sequence, which encodes a previously unidentified lignin biosynthetic pathway enzyme, sinapyl alcohol dehydrogenase (SAD) that regulates the biosynthesis of syringyl lignin in plants. Also provided are methods for incorporating this novel SAD gene sequence or substantially similar sequences into a plant genome for genetic engineering of syringyl-enriched lignin in plants.

  14. Solubilization of lignin by the ruminal anaerobic fungus Neocallimastix patriciarum.

    PubMed Central

    McSweeney, C S; Dulieu, A; Katayama, Y; Lowry, J B

    1994-01-01

    The ability of the ruminal anaerobic phycomycete Neocallimastix patriciarum to digest model lignin compounds and lignified structures in plant material was studied in batch culture. The fungus did not degrade or transform model lignin compounds that were representative of the predominant intermonomer linkages in lignin, nor did it solubilize acid detergent lignin that had been isolated from spear grass. In a stem fraction of sorghum, 33.6% of lignin was apparently solubilized by the fungus. Solubilization of ester- and either-linked phenolics accounted for 9.2% of the lignin released. The amounts of free phenolic acids detected in culture fluid were equivalent to the apparent loss of ester-linked phenolics from the sorghum substrate. However, the fungus was unable to cleave the ether bond in hydroxycinnamic acid bridges that cross-link lignin and polysaccharide. It is suggested that the majority of the solubilized lignin fraction was a lignin carbohydrate complex containing ether-linked hydroxycinnamic acids. The lignin carbohydrate complex was probably solubilized through dissolution of xylan in the lignin-xylan matrix rather than by lignin depolymerization. PMID:8085834

  15. Direct production of naphthenes and paraffins from lignin.

    PubMed

    Kong, Jiechen; He, Mingyuan; Lercher, Johannes A; Zhao, Chen

    2015-12-25

    The utilization of lignin as a fuel precursor has attracted attention, and a novel and facile process has been developed for one-pot conversion of lignin into cycloalkanes and alkanes with Ni catalysts under moderate conditions. This cascade hydrodeoxygenation approach may open the route to a new promising technique for direct liquefaction of lignin to hydrocarbons. PMID:26478925

  16. Caterpillar feeding responses to sorghum leaves with altered lignin levels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Production of liquid fuels from biomass is impeded by the presence of lignin. Plants with lower or altered lignin are more amenable to lignocellulosic conversion to ethanol and other biofuels, but may be more susceptible to insect damage where lignin is an important resistance factor. Sorghum, Sorg...

  17. Synthesis and characterization of aminated lignin.

    PubMed

    Pan, Hong; Sun, Gang; Zhao, Tao

    2013-08-01

    Amination of lignin can bring reactive amino groups onto the natural polymer and enable it to be employed in engineering materials. The amination reaction was successfully implemented after some of the hydroxyl groups on lignin were epoxidized. The resulted products showed a great quantity of primary amine group and secondary amine group which can be used as curing agents of epoxy resin. The results revealed that several factors including reaction temperature and time, as well as ratios of compounds, could influence the epoxidation and amination reactions. The resulted products were characterized by FT-IR spectra, (1)H NMR, (13)C NMR, element analysis, XPS and thermogravimetry analysis. PMID:23618954

  18. Process for producing phenolic compounds from lignins

    DOEpatents

    Agblevor, Foster A.

    1998-01-01

    A process for the production of low molecular weight phenolic compounds from lignins through the pyrolysis of the lignins in the presence of a strong base. In a preferred embodiment, potassium hydroxide is present in an amount of from about 0.1% to about 5% by weight, the pyrolysis temperature is from about 400.degree. C. to about 600.degree. C. at atmospheric pressure, and the time period for substantial completion of the reaction is from about 1-3 minutes. Examples of low molecular weight phenolic compounds produced include methoxyphenols, non-methoxylated phenols, and mixtures thereof.

  19. Process for producing phenolic compounds from lignins

    DOEpatents

    Agblevor, F.A.

    1998-09-15

    A process is described for the production of low molecular weight phenolic compounds from lignins through the pyrolysis of the lignins in the presence of a strong base. In a preferred embodiment, potassium hydroxide is present in an amount of from about 0.1% to about 5% by weight, the pyrolysis temperature is from about 400 C to about 600 C at atmospheric pressure, and the time period for substantial completion of the reaction is from about 1--3 minutes. Examples of low molecular weight phenolic compounds produced include methoxyphenols, non-methoxylated phenols, and mixtures thereof. 16 figs.

  20. Intermediates and products of synthetic lignin (dehydrogenative polymerizate) degradation by Phlebia tremellosa.

    PubMed Central

    Reid, I D

    1991-01-01

    Agitated, nitrogen-limited cultures of Phlebia tremellosa caused substantial changes in the distribution of 14C-labelled synthetic lignin (dehydrogenative polymerizate [DHP]) between water-soluble, dioxane-soluble, alkali-soluble, and insoluble fractions before much lignin carbon was metabolized to CO2. First, the insoluble form increased at the expense of the dioxane-soluble form. Later, the amounts of alkali-soluble and water-soluble 14C increased, and release of 14CO2 began. The molecular weight distribution of the dioxane-soluble lignin remained constant during degradation, but that of the water-soluble fraction changed to higher molecular weights. Culture agitation accelerated the attachment of suspended DHP to the mycelia and stimulated production of water-soluble 14C and 14CO2. The nonionic detergent Tween 80 also hastened release of 14CO2 and increased the early conversion of dioxane-soluble DHP to the alkali-soluble and insoluble forms. Oxidative polymerization is suggested as the first step in degradation of DHP by P. tremellosa. PMID:1746943

  1. Polymerization of perfluorobutadiene

    NASA Technical Reports Server (NTRS)

    Newman, J.; Toy, M. S.

    1970-01-01

    Diisopropyl peroxydicarbonate dissolved in liquid perfluorobutadiene is conducted in a sealed vessel at the autogenous pressure of polymerization. Reaction temperature, ratio of catalyst to monomer, and amount of agitation determine degree of polymerization and product yield.

  2. Lignin Degradation in a Coastal Groundwater Aquifer: a Useful Tracer?

    NASA Astrophysics Data System (ADS)

    Howley, E. M.; Jex, C.; Andersen, M. S.; Baker, A.; Zainuddin, N. S.; Meredith, K.; Wells, E.; McDonald, J.; Khan, S.; Blyth, A. J.; Spencer, R. G.

    2014-12-01

    Lignin as a biomarker in soils, peat, lakes and intertidal and marine sediment cores has been widely researched in the last four decades. The biogeochemical processes controlling their distribution and composition include fractionation due to phase changes, mineral binding, and abiotic and biotic decay. However, there appears to be no studies in the literature describing the concentration and composition of lignin in groundwater aquifers, despite lignin tracing having the potential to differentiate between types of vegetation and recharge source. In the latter case aquifers could potentially be a source of old, degradation resistant lignin. In this study, we characterise the lignin composition in groundwater samples from a coastal sand aquifer, in SE Australia. We compare these data with lignin composition of fresh vegetation samples from the study site, and with lignin data from other environments in the literature. Groundwater samples were also analysed for Dissolved Organic Carbon (DOC) and inorganic chemistry (major ions, Dissolved Inorganic Carbon (DIC) and redox sensitive species) to investigate lignin fractionation processes. To achieve this, the groundwater lignin composition was compared to the total DOC and DIC in the samples and the prevailing redox reactions. The lignin composition in groundwater was found to be unrelated to the surrounding surface vegetation, indicating significant alteration by biogeochemical processes along its flow paths. We identify potential lignin degradation zones, via determination of total OC consumed through redox reactions and microbial activity. In conclusion, this study, by closely examining the correlations of lignin phenols in groundwater with lignin in surface waters, as well as biogeochemical processes in the aquifer is shedding a new light on the ability of lignin as a biomarker in these subsurface systems. To our knowledge, this is the first attempt to assess the usefulness of lignin as a tracer in groundwater.

  3. Polymerization Reactor Engineering.

    ERIC Educational Resources Information Center

    Skaates, J. Michael

    1987-01-01

    Describes a polymerization reactor engineering course offered at Michigan Technological University which focuses on the design and operation of industrial polymerization reactors to achieve a desired degree of polymerization and molecular weight distribution. Provides a list of the course topics and assigned readings. (TW)

  4. Identifying New Lignin Bioengineering Targets: Monolignol Substitute Impacts on Lignin Formation and Cell Wall Utilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent discoveries highlighting the metabolic malleability of plant lignification indicate that lignin can be engineered to dramatically alter its composition and properties. Current plant engineering efforts are primarily aimed at manipulating the biosynthesis of normal monolignols, but in the futu...

  5. Identifying New Lignin Bioengineering Targets: 1. Monolignol Substitute Impacts on Lignin Formation and Cell Wall Fermentability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Recent discoveries highlighting the metabolic malleability of plant lignification indicate that lignin can be engineered to dramatically alter its composition and properties. Current plant engineering efforts are primarily aimed at manipulating the biosynthesis of normal monolignols but,...

  6. Lignin-blocking treatment of biomass and uses thereof

    DOEpatents

    Yang, Bin; Wyman, Charles E.

    2009-10-20

    Disclosed is a method for converting cellulose in a lignocellulosic biomass. The method provides for a lignin-blocking polypeptide and/or protein treatment of high lignin solids. The treatment enhances cellulase availability in cellulose conversion. Cellulase efficiencies are improved by the protein or polypeptide treatment. The treatment may be used in combination with steam explosion and acid prehydrolysis techniques. Hydrolysis yields from lignin containing biomass are enhanced 5-20%, and enzyme utilization is increased from 10% to 50%. Thus, a more efficient and economical method of processing lignin containing biomass materials utilizes a polypeptide/protein treatment step that effectively blocks lignin binding of cellulase.

  7. Nylon biodegradation by lignin-degrading fungi.

    PubMed Central

    Deguchi, T; Kakezawa, M; Nishida, T

    1997-01-01

    The biodegradation of nylon by lignin-degrading fungi was investigated. The fungus IZU-154 significantly degraded nylon-66 membrane under ligninolytic conditions. Nuclear magnetic resonance analysis showed that four end groups, CHO, NHCHO, CH3, and CONH2, were formed in the biodegraded nylon-66 membranes, suggesting that nylon-66 was degraded oxidatively. PMID:8979361

  8. Pyrolysis mechanisms of lignin model compounds

    SciTech Connect

    Britt, P.F.; Buchanan, A.C. III; Cooney, M.J.

    1997-06-01

    The flash vacuum pyrolysis of lignin model compounds was studied under conditions optimized for the production of liquid products to provide mechanistic insight into the reaction pathways that lead to product formation. The major reaction products can be explained by cleavage of the C-O either linkage by a free radial or concerted 1,2-elimination.

  9. Three-dimensional model of lignin structure

    SciTech Connect

    Jurasek, L.

    1995-12-01

    An attempt to build a three-dimensional model of lignin structure using a computer program is described. The program simulates the biosynthesis of spruce lignin by allowing coniferyl alcohol subunits to be added randomly by six different types of linkages, assumed to be most common. The simulated biosynthesis starts from a number of seed points within restricted space, corresponding to 50 mM initial concentration of coniferyl alcohol. Rules of three-dimensional packing of the subunits within the lignin macro-molecule are observed during the simulated biosynthetic process. Branched oligomeric structures thus generated form crosslinks at those positions where the chains grow close enough to form a link. Inter-chain crosslinking usually joins the oligomers into one macromolecule. Intra-chain crosslinks are also formed and result in closed loops. Typically, a macromolecule with molecular weight of approx. 2 x 105 is formed, with internal density of 1.35g/cm3. Various characteristics of the internal structure, such as branching, crosslinking, bond frequencies, and chain length distribution are described. Breakdown of the polymer was also simulated and the effect of closed loops on the weight average molecular weight is shown. The effect of the shape of the biosynthetic space on the degree of crosslinking is discussed and predictions of the overall molecular shape of lignin particles are made.

  10. Flash vacuum pyrolysis of lignin model compounds

    SciTech Connect

    Cooney, M.J.; Britt, P.F.; Buchanan, A.C. III

    1997-03-01

    Despite the extensive research into the pyrolysis of lignin, the underlying chemical reactions that lead to product formation are poorly understood. Detailed mechanistic studies on the pyrolysis of biomass and lignin under conditions relevant to current process conditions could provide insight into utilizing this renewable resource for the production of chemicals and fuel. Currently, flash or fast pyrolysis is the most promising process to maximize the yields of liquid products (up to 80 wt %) from biomass by rapidly heating the substrate to moderate temperatures, typically 500{degrees}C, for short residence times, typically less than two seconds. To provide mechanistic insight into the primary reaction pathways under process relevant conditions, we are investigating the flash vacuum pyrolysis (FVP) of lignin model compounds that contain a {beta}-ether. linkage and {alpha}- or {gamma}-alcohol, which are key structural elements in lignin. The dominant products from the FVP of PhCH{sub 2}CH{sub 2}OPh (PPE), PhC(OH)HCH{sub 2}OPh, and PhCH{sub 2}CH(CH{sub 2}OH)OPh at 500{degrees}C can be attributed to homolysis of the weakest bond in the molecule (C-O bond) or 1,2-elimination. Surprisingly, the hydroxy-substituent dramatically increases the decomposition of PPE. It is proposed that internal hydrogen bonding is accelerating the reaction.

  11. Kinetic Model Development for Lignin Pyrolysis

    SciTech Connect

    Clark, J.; Robichaud, D.; Nimlos, M.

    2012-01-01

    Lignin pyrolysis poses a significant barrier to the formation of liquid fuel products from biomass. Lignin pyrolyzes at higher temperatures than other biomass components (e.g. cellulose and hemi-cellulose) and tends to form radicals species that lead to cross-linking and ultimately char formation. A first step in the advancement of biomass-to-fuel technology is to discover the underlying mechanisms that lead to the breakdown of lignin at lower temperatures into more stable and usable products. We have investigated the thermochemistry of the various inter-linkage units found in lignin (B-O4, a-O4, B-B, B-O5, etc) using electronic structure calculations at the M06-2x/6-311++G(d,p) on a series of dimer model compounds. In addition to bond homolysis reactions, a variety of concerted elimination pathways are under investigation that tend to produce closed-shell stable products. Such a bottom-up approach could aid in the targeted development of catalysts that produce more desirable products under less severe reactor conditions.

  12. Computational Mechanistic Studies of Acid-Catalyzed Lignin Model Dimers for Lignin Depolymerization

    SciTech Connect

    Kim, S.; Sturgeon, M. R.; Chmely, S. C.; Paton, R. S.; Beckham, G. T.

    2013-01-01

    Lignin is a heterogeneous alkyl-aromatic polymer that constitutes up to 30% of plant cell walls, and is used for water transport, structure, and defense. The highly irregular and heterogeneous structure of lignin presents a major obstacle in the development of strategies for its deconstruction and upgrading. Here we present mechanistic studies of the acid-catalyzed cleavage of lignin aryl-ether linkages, combining both experimental studies and quantum chemical calculations. Quantum mechanical calculations provide a detailed interpretation of reaction mechanisms including possible intermediates and transition states. Solvent effects on the hydrolysis reactions were incorporated through the use of a conductor-like polarizable continuum model (CPCM) and with cluster models including explicit water molecules in the first solvation shell. Reaction pathways were computed for four lignin model dimers including 2-phenoxy-phenylethanol (PPE), 1-(para-hydroxyphenyl)-2-phenoxy-ethanol (HPPE), 2-phenoxy-phenyl-1,3-propanediol (PPPD), and 1-(para-hydroxyphenyl)-2-phenoxy-1,3-propanediol (HPPPD). Lignin model dimers with a para-hydroxyphenyl ether (HPPE and HPPPD) show substantial differences in reactivity relative to the phenyl ether compound (PPE and PPPD) which have been clarified theoretically and experimentally. The significance of these results for acid deconstruction of lignin in plant cell walls will be discussed.

  13. Phoma herbarum, a soil fungus able to grow on natural lignin and synthetic lignin (DHP) as sole carbon source and cause lignin degradation.

    PubMed

    Bi, Ran; Lawoko, Martin; Henriksson, Gunnar

    2016-08-01

    The fungus Phoma herbarum isolated from soil showed growth on highly pure lignin extracted from spruce wood and on synthetic lignin (DHP). The lignin remaining after cultivation was shown to have a lower molecular weight. The reduction in the numbers of ether linkages of the extracted lignins was also observed by derivatization followed by reductive cleavage (DFRC) in combination with (31)P NMR studies. The fungal strain showed an ability to degrade synthetic lignin by extracellular catalysts. GC-MS was applied to study the evolution of low molar mass adducts, e.g., monolignols and it was shown that a reduced coniferyl alcohol product was produced from DHP in a cell-free environment. The work has demonstrated the ability of soil microbes to grow on lignin as sole carbon source. The potential impact is in the production of low molar mass renewable phenols for material application. PMID:27260523

  14. Discovery of 12-mer peptides that bind to wood lignin

    PubMed Central

    Yamaguchi, Asako; Isozaki, Katsuhiro; Nakamura, Masaharu; Takaya, Hikaru; Watanabe, Takashi

    2016-01-01

    Lignin, an abundant terrestrial polymer, is the only large-volume renewable feedstock composed of an aromatic skeleton. Lignin has been used mostly as an energy source during paper production; however, recent interest in replacing fossil fuels with renewable resources has highlighted its potential value in providing aromatic chemicals. Highly selective degradation of lignin is pivotal for industrial production of paper, biofuels, chemicals, and materials. However, few studies have examined natural and synthetic molecular components recognizing the heterogeneous aromatic polymer. Here, we report the first identification of lignin-binding peptides possessing characteristic sequences using a phage display technique. The consensus sequence HFPSP was found in several lignin-binding peptides, and the outer amino acid sequence affected the binding affinity of the peptides. Substitution of phenylalanine7 with Ile in the lignin-binding peptide C416 (HFPSPIFQRHSH) decreased the affinity of the peptide for softwood lignin without changing its affinity for hardwood lignin, indicating that C416 recognised structural differences between the lignins. Circular dichroism spectroscopy demonstrated that this peptide adopted a highly flexible random coil structure, allowing key residues to be appropriately arranged in relation to the binding site in lignin. These results provide a useful platform for designing synthetic and biological catalysts selectively bind to lignin. PMID:26903196

  15. Discovery of 12-mer peptides that bind to wood lignin.

    PubMed

    Yamaguchi, Asako; Isozaki, Katsuhiro; Nakamura, Masaharu; Takaya, Hikaru; Watanabe, Takashi

    2016-01-01

    Lignin, an abundant terrestrial polymer, is the only large-volume renewable feedstock composed of an aromatic skeleton. Lignin has been used mostly as an energy source during paper production; however, recent interest in replacing fossil fuels with renewable resources has highlighted its potential value in providing aromatic chemicals. Highly selective degradation of lignin is pivotal for industrial production of paper, biofuels, chemicals, and materials. However, few studies have examined natural and synthetic molecular components recognizing the heterogeneous aromatic polymer. Here, we report the first identification of lignin-binding peptides possessing characteristic sequences using a phage display technique. The consensus sequence HFPSP was found in several lignin-binding peptides, and the outer amino acid sequence affected the binding affinity of the peptides. Substitution of phenylalanine7 with Ile in the lignin-binding peptide C416 (HFPSPIFQRHSH) decreased the affinity of the peptide for softwood lignin without changing its affinity for hardwood lignin, indicating that C416 recognised structural differences between the lignins. Circular dichroism spectroscopy demonstrated that this peptide adopted a highly flexible random coil structure, allowing key residues to be appropriately arranged in relation to the binding site in lignin. These results provide a useful platform for designing synthetic and biological catalysts selectively bind to lignin. PMID:26903196

  16. Effect of lignin content on changes occurring in poplar cellulose ultrastructure during dilute acid pretreatment

    DOE PAGESBeta

    Sun, Qining; Foston, Marcus; Meng, Xianzhi; Sawada, Daisuke; Pingali, Sai Venkatesh; O’Neill, Hugh M.; Li, Hongjia; Wyman, Charles E.; Langan, Paul; Ragauskas, Art J.; et al

    2014-10-14

    Obtaining a better understanding of the complex mechanisms occurring during lignocellulosic deconstruction is critical to the continued growth of renewable biofuel production. A key step in bioethanol production is thermochemical pretreatment to reduce plant cell wall recalcitrance for downstream processes. Previous studies of dilute acid pretreatment (DAP) have shown significant changes in cellulose ultrastructure that occur during pretreatment, but there is still a substantial knowledge gap with respect to the influence of lignin on these cellulose ultrastructural changes. This study was designed to assess how the presence of lignin influences DAP-induced changes in cellulose ultrastructure, which might ultimately have largemore » implications with respect to enzymatic deconstruction efforts. Native, untreated hybrid poplar (Populus trichocarpa x Populus deltoids) samples and a partially delignified poplar sample (facilitated by acidic sodium chlorite pulping) were separately pretreated with dilute sulfuric acid (0.10 M) at 160°C for 15 minutes and 35 minutes, respectively . Following extensive characterization, the partially delignified biomass displayed more significant changes in cellulose ultrastructure following DAP than the native untreated biomass. With respect to the native untreated poplar, delignified poplar after DAP (in which approximately 40% lignin removal occurred) experienced: increased cellulose accessibility indicated by increased Simons’ stain (orange dye) adsorption from 21.8 to 72.5 mg/g, decreased cellulose weight-average degree of polymerization (DPw) from 3087 to 294 units, and increased cellulose crystallite size from 2.9 to 4.2 nm. These changes following DAP ultimately increased enzymatic sugar yield from 10 to 80%. We conclude that, overall, the results indicate a strong influence of lignin content on cellulose ultrastructural changes occurring during DAP. With the reduction of lignin content during DAP, the enlargement of

  17. Computational inference of the structure and regulation of the lignin pathway in Panicum virgatum

    SciTech Connect

    Faraji, Mojdeh; Fonseca, Luis L.; Escamilla-Treviño, Luis; Dixon, Richard A.; Voit, Eberhard O.

    2015-09-17

    Switchgrass is a prime target for biofuel production from inedible plant parts and has been the subject of numerous investigations in recent years. Yet, one of the main obstacles to effective biofuel production remains to be the major problem of recalcitrance. Recalcitrance emerges in part from the 3-D structure of lignin as a polymer in the secondary cell wall. Lignin limits accessibility of the sugars in the cellulose and hemicellulose polymers to enzymes and ultimately decreases ethanol yield. Monolignols, the building blocks of lignin polymers, are synthesized in the cytosol and translocated to the plant cell wall, where they undergo polymerization. The biosynthetic pathway leading to monolignols in switchgrass is not completely known, and difficulties associated with in vivo measurements of these intermediates pose a challenge for a true understanding of the functioning of the pathway. In this study, a systems biological modeling approach is used to address this challenge and to elucidate the structure and regulation of the lignin pathway through a computational characterization of alternate candidate topologies. The analysis is based on experimental data characterizing stem and tiller tissue of four transgenic lines (knock-downs of genes coding for key enzymes in the pathway) as well as wild-type switchgrass plants. These data consist of the observed content and composition of monolignols. The possibility of a G-lignin specific metabolic channel associated with the production and degradation of coniferaldehyde is examined, and the results support previous findings from another plant species. The computational analysis suggests regulatory mechanisms of product inhibition and enzyme competition, which are well known in biochemistry, but so far had not been reported in switchgrass. By including these mechanisms, the pathway model is able to represent all observations. In conclusion, the results show that the presence of the coniferaldehyde channel is necessary

  18. Computational inference of the structure and regulation of the lignin pathway in Panicum virgatum

    DOE PAGESBeta

    Faraji, Mojdeh; Fonseca, Luis L.; Escamilla-Treviño, Luis; Dixon, Richard A.; Voit, Eberhard O.

    2015-09-17

    Switchgrass is a prime target for biofuel production from inedible plant parts and has been the subject of numerous investigations in recent years. Yet, one of the main obstacles to effective biofuel production remains to be the major problem of recalcitrance. Recalcitrance emerges in part from the 3-D structure of lignin as a polymer in the secondary cell wall. Lignin limits accessibility of the sugars in the cellulose and hemicellulose polymers to enzymes and ultimately decreases ethanol yield. Monolignols, the building blocks of lignin polymers, are synthesized in the cytosol and translocated to the plant cell wall, where they undergomore » polymerization. The biosynthetic pathway leading to monolignols in switchgrass is not completely known, and difficulties associated with in vivo measurements of these intermediates pose a challenge for a true understanding of the functioning of the pathway. In this study, a systems biological modeling approach is used to address this challenge and to elucidate the structure and regulation of the lignin pathway through a computational characterization of alternate candidate topologies. The analysis is based on experimental data characterizing stem and tiller tissue of four transgenic lines (knock-downs of genes coding for key enzymes in the pathway) as well as wild-type switchgrass plants. These data consist of the observed content and composition of monolignols. The possibility of a G-lignin specific metabolic channel associated with the production and degradation of coniferaldehyde is examined, and the results support previous findings from another plant species. The computational analysis suggests regulatory mechanisms of product inhibition and enzyme competition, which are well known in biochemistry, but so far had not been reported in switchgrass. By including these mechanisms, the pathway model is able to represent all observations. In conclusion, the results show that the presence of the coniferaldehyde channel is

  19. Effect of lignin content on changes occurring in poplar cellulose ultrastructure during dilute acid pretreatment

    SciTech Connect

    Sun, Qining; Foston, Marcus; Meng, Xianzhi; Sawada, Daisuke; Pingali, Sai Venkatesh; O’Neill, Hugh M.; Li, Hongjia; Wyman, Charles E.; Langan, Paul; Ragauskas, Art J.; Kumar, Rajeev

    2014-10-14

    Obtaining a better understanding of the complex mechanisms occurring during lignocellulosic deconstruction is critical to the continued growth of renewable biofuel production. A key step in bioethanol production is thermochemical pretreatment to reduce plant cell wall recalcitrance for downstream processes. Previous studies of dilute acid pretreatment (DAP) have shown significant changes in cellulose ultrastructure that occur during pretreatment, but there is still a substantial knowledge gap with respect to the influence of lignin on these cellulose ultrastructural changes. This study was designed to assess how the presence of lignin influences DAP-induced changes in cellulose ultrastructure, which might ultimately have large implications with respect to enzymatic deconstruction efforts. Native, untreated hybrid poplar (Populus trichocarpa x Populus deltoids) samples and a partially delignified poplar sample (facilitated by acidic sodium chlorite pulping) were separately pretreated with dilute sulfuric acid (0.10 M) at 160°C for 15 minutes and 35 minutes, respectively . Following extensive characterization, the partially delignified biomass displayed more significant changes in cellulose ultrastructure following DAP than the native untreated biomass. With respect to the native untreated poplar, delignified poplar after DAP (in which approximately 40% lignin removal occurred) experienced: increased cellulose accessibility indicated by increased Simons’ stain (orange dye) adsorption from 21.8 to 72.5 mg/g, decreased cellulose weight-average degree of polymerization (DPw) from 3087 to 294 units, and increased cellulose crystallite size from 2.9 to 4.2 nm. These changes following DAP ultimately increased enzymatic sugar yield from 10 to 80%. We conclude that, overall, the results indicate a strong influence of lignin content on cellulose ultrastructural changes occurring during DAP. With the reduction of lignin content during DAP, the enlargement of

  20. Reactions of Lignin Model Compounds in Ionic Liquids

    SciTech Connect

    Holladay, John E.; Binder, Joseph B.; Gray, Michel J.; White, James F.; Zhang, Z. Conrad

    2009-09-15

    Lignin, a readily available form of biomass, awaits novel chemistry for converting it to valuable aromatic chemicals. Recent work has demonstrated that ionic liquids are excellent solvents for processing woody biomass and lignin. Seeking to exploit ionic liquids as media for depolymerization of lignin, we investigated reactions of lignin model compounds in these solvents. Using Brønsted acid catalysts in 1-ethyl-3-methylimidazolium triflate at moderate temperatures, we obtained up to 11.6% yield of the dealkylation product guaiacol from the model compound eugenol and cleaved phenethyl phenyl ether, a model for lignin ethers. Despite these successes, acid catalysis failed in dealkylation of the unsaturated model compound 4-ethylguaiacol and did not produce monomeric products from organosolv lignin, demonstrating that further work is required to understand the complex chemistry of lignin depolymerization.

  1. Isolation of a bacterium capable of degrading peanut hull lignin

    SciTech Connect

    Kerr, T.A.; Kerr, R.D.; Benner, R.

    1983-11-01

    Thirty-seven bacterial strains capable of degrading peanut hull lignin were isolated by using four types of lignin preparations and hot-water-extracted peanut hulls. One of the isolates, tentatively identified as Arthrobacter species, was capable of utilizing all four lignin preparations as well as extracted peanut hulls as a sole source of carbon. The bacterium was also capable of degrading specifically labeled (/sup 14/C) lignin-labeled lignocellulose and (/sup 14/C)cellulose-labeled lignocellulose from the cordgrass Spartina alterniflora and could also degrade (/sup 14/C) Kraft lignin from slash pine. After 10 days of incubation with (/sup 14/C) cellulose-labeled lignocellulose or (/sup 14/C) lignin-labeled lignocellulose from S. alterniflora, the bacterium mineralized 6.5% of the polysaccharide component and 2.9% of the lignin component. (Refs. 24).

  2. Poplar lignin decomposition by gram-negative aerobic bacteria

    SciTech Connect

    Odier, E.; Janin, G.; Monties, B.

    1981-02-01

    Eleven gram-negative aerobic bacteria (Pseudomonadaceae and Neisseriaceae) out of 122 soil isolates were selected for their ability to assimilate poplar dioxane lignin without a cosubstrate. Dioxane lignin and milled wood lignin degradation rates ranged between 20 and 40% of initial content after 7 days in mineral medium, as determined by a loss of absorbance at 280 nm; 10 strains could degrade in situ lignin, as evidenced by the decrease of the acetyl bromide lignin content of microtome wood sections. No degradation of wood polysaccharides was detected. Lignin biodegradation by Pseudomonas 106 was confirmed by 14CO2 release from labeled poplar wood, although in lower yields compared with results obtained through chemical analysis based on acetyl bromide residual lignin determination. (Refs. 31).

  3. Method for recovering and using lignin in adhesive resins

    DOEpatents

    Schroeder, Herbert A.

    1993-01-01

    Lignin, or a lignin derived material, which has been significantly demethylated (e.g., the demethylated lignin found in the raffinate produced as a by-product of dimethyl sulfide production which can be carried out using the spent liquor from wood pulping operations) can be isolated by a process wherein an organic solvent is added to a lignin-containing aqueous solution. The organic solvent is typically a polar, and at least a partially water-immiscible substance such as, for example, ethyl acetate. The resulting lignin-containing aqueous solution/organic solvent mixture is acidified to produce a water layer which is discarded and an organic solvent layer which contains the demethylated lignin. Upon its recovery, the demethylated lignin is dissolved in an alkaline solution to which an aldehyde source is added to produce a resol-type resin. The aldehyde source may be formaldehyde in solution, paraformaldehyde, hexamethylenetetramine, or other aldehydes including acetaldehyde, furfural, and their derivatives.

  4. Bioinformatic and functional characterization of the basic peroxidase 72 from Arabidopsis thaliana involved in lignin biosynthesis.

    PubMed

    Herrero, Joaquín; Fernández-Pérez, Francisco; Yebra, Tatiana; Novo-Uzal, Esther; Pomar, Federico; Pedreño, Ma Ángeles; Cuello, Juan; Guéra, Alfredo; Esteban-Carrasco, Alberto; Zapata, José Miguel

    2013-06-01

    Lignins result from the oxidative polymerization of three hydroxycinnamyl (p-coumaryl, coniferyl, and sinapyl) alcohols in a reaction mediated by peroxidases. The most important of these is the cationic peroxidase from Zinnia elegans (ZePrx), an enzyme considered to be responsible for the last step of lignification in this plant. Bibliographical evidence indicates that the arabidopsis peroxidase 72 (AtPrx72), which is homolog to ZePrx, could have an important role in lignification. For this reason, we performed a bioinformatic, histochemical, photosynthetic, and phenotypical and lignin composition analysis of an arabidopsis knock-out mutant of AtPrx72 with the aim of characterizing the effects that occurred due to the absence of expression of this peroxidase from the aspects of plant physiology such as vascular development, lignification, and photosynthesis. In silico analyses indicated a high homology between AtPrx72 and ZePrx, cell wall localization and probably optimal levels of translation of AtPrx72. The histochemical study revealed a low content in syringyl units and a decrease in the amount of lignin in the atprx72 mutant plants compared to WT. The atprx72 mutant plants grew more slowly than WT plants, with both smaller rosette and principal stem, and with fewer branches and siliques than the WT plants. Lastly, chlorophyll a fluorescence revealed a significant decrease in ΦPSII and q L in atprx72 mutant plants that could be related to changes in carbon partitioning and/or utilization of redox equivalents in arabidopsis metabolism. The results suggest an important role of AtPrx72 in lignin biosynthesis. In addition, knock-out plants were able to respond and adapt to an insufficiency of lignification. PMID:23508663

  5. Purification and Characterization of a Thermostable Laccase from Trametes trogii and Its Ability in Modification of Kraft Lignin.

    PubMed

    Ai, Ming-Qiang; Wang, Fang-Fang; Huang, Feng

    2015-08-01

    A blue laccase was purified from a white rot fungus of Trametes trogii, which was a monomeric protein of 64 kDa as determined by SDS-PAGE. The enzyme acted optimally at a pH of 2.2 to 4.5 and a temperature of 70°C and showed high thermal stability, with a half-life of 1.6 h at 60°C. A broad range of substrates, including the non-phenolic azo dye methyl red, was oxidized by the laccase, and the laccase exhibited high affinity towards ABTS and syringaldazine. Moreover, the laccase was fairly metal-tolerant. A high-molecular-weight kraft lignin was effectively polymerized by the laccase, with a maximum of 6.4-fold increase in weight-average molecular weight, as demonstrated by gel permeation chromatography. Notable structural changes in the polymerized lignin were detected by Fourier transform infrared spectroscopy and 1H NMR spectroscopy. This revealed an increase in condensed structures as well as carbonyl and aliphatic hydroxyl groups. Simultaneously, phenolic hydroxyl and methoxy groups decreased. These results suggested the potential use of the laccase in lignin modification. PMID:25876603

  6. Benzoxazolin-2(3H)-one inhibits soybean growth and alters the monomeric composition of lignin.

    PubMed

    Parizotto, Angela Valderrama; Bubna, Gisele Adriana; Marchiosi, Rogério; Soares, Anderson Ricardo; Ferrarese, Maria de Lourdes Lucio; Ferrarese-Filho, Osvaldo

    2015-01-01

    The effects of the allelochemical benzoxazolin-2-(3H)-one (BOA) were evaluated on growth, lignin content and its monomers p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) in roots, stems and leaves of soybean. BOA decreased the lengths and fresh weights of roots and stems, and the fresh weights and areas of leaves. Reductions in the growth were accompanied by enhanced lignin content in all tissues. In roots, the allelochemical increased the content of H, G and S monomers as well as the overall amount of lignin (referred to as the sum of H+G+S), but did not alter the S/G ratio. In stems and leaves, BOA increased the H, G, S and H+G+S contents while decreasing the S/G ratio. In brief, BOA-induced inhibition of soybean may be due to excessive production of monomers that increase the degree of polymerization of lignin, limit cell expansion, solidify the cell wall and restrict plant growth. PMID:25826260

  7. Analytical pyrolysis of hardwood and softwood lignins and its use in lignin-type determination of hardwood vessel elements

    SciTech Connect

    Obst, J.R.

    1983-01-01

    Pyrolysis, GC and mass spectrometry were performed on milled wood lignins and wood samples. Among the major pyrolysis products identified from loblolly pine lignin were: guaiacol, 4-methylguaiacol, 4-vinylguaiacol, vanillin, coniferaldehyde and coniferyl alcohol. White oak lignin pyrolysis products included: guaiacol, 4-methylguaiacol, vanillin, 2,6-dimethoxyphenol, 4-methyl-2,6-dimethoxyphenol, syringaldehyde and sinapaldehyde. By the identification of pyrolysis products it is thus possible to classify lignins as either guaiacyl-type or syringyl/guaiacyl-type. Pyrolysis of isolated vessel elements from white oak, white birch (Betula papyrifera) and American elm (Ulmus americana) indicated that vessel lignin is of the syringyl/guaiacyl type. 14 references.

  8. Gene silencing of BnTT10 family genes causes retarded pigmentation and lignin reduction in the seed coat of Brassica napus.

    PubMed

    Zhang, Kai; Lu, Kun; Qu, Cunmin; Liang, Ying; Wang, Rui; Chai, Yourong; Li, Jiana

    2013-01-01

    Yellow-seed (i.e., yellow seed coat) is one of the most important agronomic traits of Brassica plants, which is correlated with seed oil and meal qualities. Previous studies on the Brassicaceae, including Arabidopsis and Brassica species, proposed that the seed-color trait is correlative to flavonoid and lignin biosynthesis, at the molecular level. In Arabidopsis thaliana, the oxidative polymerization of flavonoid and biosynthesis of lignin has been demonstrated to be catalyzed by laccase 15, a functional enzyme encoded by the AtTT10 gene. In this study, eight Brassica TT10 genes (three from B. napus, three from B. rapa and two from B. oleracea) were isolated and their roles in flavonoid oxidation/polymerization and lignin biosynthesis were investigated. Based on our phylogenetic analysis, these genes could be divided into two groups with obvious structural and functional differentiation. Expression studies showed that Brassica TT10 genes are active in developing seeds, but with differential expression patterns in yellow- and black-seeded near-isogenic lines. For functional analyses, three black-seeded B. napus cultivars were chosen for transgenic studies. Transgenic B. napus plants expressing antisense TT10 constructs exhibited retarded pigmentation in the seed coat. Chemical composition analysis revealed increased levels of soluble proanthocyanidins, and decreased extractable lignin in the seed coats of these transgenic plants compared with that of the controls. These findings indicate a role for the Brassica TT10 genes in proanthocyanidin polymerization and lignin biosynthesis, as well as seed coat pigmentation in B. napus. PMID:23613820

  9. Trends in lignin modification: a comprehensive analysis of the effects of genetic manipulations/mutations on lignification and vascular integrity

    NASA Technical Reports Server (NTRS)

    Anterola, Aldwin M.; Lewis, Norman G.

    2002-01-01

    /mutations also established that a depletion in monolignol supply reduced both lignin contents supply reduced both lignin contents and vascular integrity, with a concomitant shift towards (upstream) metabolite build-up and/or shunting.The extraordinary claims of involvement of surrogate monomers (2-methoxybenzaldehyde, feruloyl tyramine, vanillic acid, etc.) in lignification were fully disproven and put to rest, with the investigators themselves having largely retracted former claims. Furthermore analysis of the well-known bm1 mutation, a presumed CAD disrupted system, apparently revealed that both G and S lignin components were reduced. This seems to imply that there is no monolignol specific dehydrogenase, such as the recently described sinapyl alcohol dehydrogenase (SAD) for sinapyl alcohol formation. Nevertheless, different CAD isoforms of differing homology seem to be operative in different lignifying cell types, thereby giving the G-enriched and G/S-enriched lignin biopolymers, respectively. For the G-lignin forming network, however, the CAD isoform is apparently catalytically less efficient with all three monolignols than that additionally associated with the corresponding G/S lignin forming network(s), which can more efficiently use all three monolignols. However, since CAD does not determine either H, G, or S designation, it again serves in a subsidiary role-albeit using different isoforms for different cell wall developmental and cell wall type responses.The results from this analysis contrasts further with speculations of some early investigators, who had viewed lignin assembly as resulting from non-specific oxidative coupling of monolignols and subsequent random polymerization. At that time, though, the study of the complex biological (biochemical) process of lignin assembly had begun without any of the (bio)chemical tools to either address or answer the questions posed as to how its formation might actually occur. Today, by contrast, there is growing recognition of

  10. Modulation of mutagenicity of various mutagens by lignin derivatives.

    PubMed

    Mikulásová, Mária; Kosíková, Bozena

    2003-03-01

    The effect of lignin on cytotoxicity, mutagenicity and SOS response induced by 4-nitroquinoline-N-oxide (4NQO), 3-(5-nitro-2-furyl)acrylic acid (5NFAA), 2-nitrofluorene (2NF) as well as hydrogen peroxide was investigated in bacterial assay systems, i.e. the Ames test with Salmonella typhimurium TA98, TA100, TA102 and the SOS chromotest with Escherichia coli PQ37. Lignin preparations obtained from beech wood significantly decreased the mutagenicity induced by 4NQO, 2NF and H(2)O(2). In the case of mutagenicity induced by 5NFAA the effect was lower. Antimutagenic properties of lignin samples tested were shown also by SOS chromotest where lignin inhibited the ability of both 4NQO and H(2)O(2) to induce the SOS response. Derivatives of lignin including those from soft and hard wood, as well as from annual plants differ in their efficiency to inhibit the induction of the SOS response. The modified lignins isolated from beech and spruce wood exhibit a high level of protection. Lignins from annual plants-corn cobs and straw-only marginally evoked an antimutagenic response, but their effect was increased by hydrothermic treatment of both annual plants. The results obtained indicate the prospective utilization of lignin preparations as additive in chemo-prevention. The antimutagenic effect of lignin samples varies with the method of isolation and modification, as well as with the genetic origin of the lignin. PMID:12581535

  11. Lignin geochemistry of sediments from the Narragansett Bay Estuary

    NASA Astrophysics Data System (ADS)

    Requejo, A. G.; Brown, John S.; Boehm, Paul D.

    1986-12-01

    Cupric oxide oxidation has been employed to characterize the lignin geochemistry of Narragansett Bay sediments. Lignin concentrations throughout the estuary are low when expressed on a carbon-normalized basis, but can be characterized as enriched when expressed on a mass-normalized basis. This implies substantial dilution of the sedimentary lignin by inputs of lignin-poor carbon. Lignin concentrations do not correlate with the 13C isotopic composition of the sedimentary organic matter. These results are consistent with a sediment lignin component consisting of varying amounts of vascular plant debris and lignin-depleted organic matter, the latter originating from both marine (planktonic) and terrestrial (uncharacterized) sources. Compositional plots of lignin-derived phenols show that sediments in the upper estuary are influenced to a greater extent by gymnosperm lignin sources than those in the mid-and lower estuary. Given the extent to which the upper estuary is affected by pollution sources, inputs from anthropogenic discharges are the most likely cause of these compositional differences. However, an evaluation of processed paper products as an "anthropogenic" lignin source indicates that the lignin content of these materials is insufficient to account for the levels found in the sediments. Subsurface lignin compositions at an upper estuary site reveal that lignin originating from the inferred anthropogenic sources disappears at a depth shallower than that which would be expected based on the distribution of other trace organic pollutants (hydrocarbons and several synthetic organic compounds). We speculate that differences in either the depositional history or the degree of preservation of these two compound classes are responsible for the observed trends.

  12. Dynamics and turnover of lignins in soils: a review

    NASA Astrophysics Data System (ADS)

    Thevenot, M.; Rumpel, C.; Dignac, M.-F.

    2009-04-01

    Lignins are amongst the most studied bio-macromolecules in natural environments, for their properties as biomarkers and their suggested influence on soil organic carbon dynamics. A large number of methods exists to characterize lignins, but the alkaline CuO oxidation is the most used for determining lignin fate in soils. The CuO oxidation products of lignins yield quantitative information (sum of V, S and C monomers) as well as qualitative information on the degradation of lignins (S/V, C/V, (Ad/Al)V,S…). The CuO-lignin products provide information on lignins but also on the environment and particularly on the present and past vegetation. Data from several studies were compiled in order to evaluate the relations between lignins in soils and various environmental parameters. The results of the multiple correspondence analysis (MCA) performed suggest that the lignin content in soils is directly related to the C and N contents, confirming its contribution to the pool of organic carbon. The lignin distribution appears also related to the climate and to the soil texture, which suggests the impact of these parameters on the lignin degradation and retention in soils, as observed for organic carbon (Burke et al., 1989). The total lignin content generally decreases with the soil depth and with the decreasing size of the granulometric fractions. Hence, the more lignins are degraded, the more they are associated with the finest fractions. In addition, it appears that lignin contents are linked to land-use. Thus, in accordance with the land cover, management type and amount of annual input, the forest soils are described by high contents of VSC, C and N, in contrast with the arable land. Lignins were often considered to greatly participate to the stock of slowly degradable and stable carbon in soils. However, several studies suggest that lignin turnover can be more rapid than that of the bulk soil organic carbon (SOC), suggesting that they are not stabilized in soil. On the

  13. De novo assembly, transcriptome characterization, lignin accumulation, and anatomic characteristics: novel insights into lignin biosynthesis during celery leaf development.

    PubMed

    Jia, Xiao-Ling; Wang, Guang-Long; Xiong, Fei; Yu, Xu-Run; Xu, Zhi-Sheng; Wang, Feng; Xiong, Ai-Sheng

    2015-01-01

    Celery of the family Apiaceae is a biennial herb that is cultivated and consumed worldwide. Lignin is essential for cell wall structural integrity, stem strength, water transport, mechanical support, and plant pathogen defense. This study discussed the mechanism of lignin formation at different stages of celery development. The transcriptome profile, lignin distribution, anatomical characteristics, and expression profile of leaves at three stages were analyzed. Regulating lignin synthesis in celery growth development has a significant economic value. Celery leaves at three stages were collected, and Illumina paired-end sequencing technology was used to analyze large-scale transcriptome sequences. From Stage 1 to 3, the collenchyma and vascular bundles in the petioles and leaf blades thickened and expanded, whereas the phloem and the xylem extensively developed. Spongy and palisade mesophyll tissues further developed and were tightly arranged. Lignin accumulation increased in the petioles and the mesophyll (palisade and spongy), and the xylem showed strong lignification. Lignin accumulation in different tissues and at different stages of celery development coincides with the anatomic characteristics and transcript levels of genes involved in lignin biosynthesis. Identifying the genes that encode lignin biosynthesis-related enzymes accompanied by lignin distribution may help elucidate the regulatory mechanisms of lignin biosynthesis in celery. PMID:25651889

  14. Effect of lignin on water vapor barrier, mechanical, and structural properties of agar/lignin composite films.

    PubMed

    Shankar, Shiv; Reddy, Jeevan Prasad; Rhim, Jong-Whan

    2015-11-01

    Biodegradable composite films were prepared using two renewable resources based biopolymers, agar and lignin alkali. The lignin was used as a reinforcing material and agar as a biopolymer matrix. The effect of lignin concentration (1, 3, 5, and 10wt%) on the performance of the composite films was studied. In addition, the mechanical, water vapor barrier, UV light barrier properties, FE-SEM, and TGA of the films were analyzed. The agar/lignin films exhibited higher mechanical and UV barrier properties along with lower water vapor permeability compared to the neat agar film. The FTIR and SEM results showed the compatibility of lignin with agar polymer. The swelling ratio and moisture content of agar/lignin composite films were decreased with increase in lignin content. The thermostability and char content of agar/lignin composite films increased with increased lignin content. The results suggested that agar/lignin films have a potential to be used as a UV barrier food packaging material for maintaining food safety and extending the shelf-life of the packaged food. PMID:26271435

  15. Advanced Model Compounds for Understanding Acid-Catalyzed Lignin Depolymerization: Identification of Renewable Aromatics and a Lignin-Derived Solvent.

    PubMed

    Lahive, Ciaran W; Deuss, Peter J; Lancefield, Christopher S; Sun, Zhuohua; Cordes, David B; Young, Claire M; Tran, Fanny; Slawin, Alexandra M Z; de Vries, Johannes G; Kamer, Paul C J; Westwood, Nicholas J; Barta, Katalin

    2016-07-20

    The development of fundamentally new approaches for lignin depolymerization is challenged by the complexity of this aromatic biopolymer. While overly simplified model compounds often lack relevance to the chemistry of lignin, the direct use of lignin streams poses significant analytical challenges to methodology development. Ideally, new methods should be tested on model compounds that are complex enough to mirror the structural diversity in lignin but still of sufficiently low molecular weight to enable facile analysis. In this contribution, we present a new class of advanced (β-O-4)-(β-5) dilinkage models that are highly realistic representations of a lignin fragment. Together with selected β-O-4, β-5, and β-β structures, these compounds provide a detailed understanding of the reactivity of various types of lignin linkages in acid catalysis in conjunction with stabilization of reactive intermediates using ethylene glycol. The use of these new models has allowed for identification of novel reaction pathways and intermediates and led to the characterization of new dimeric products in subsequent lignin depolymerization studies. The excellent correlation between model and lignin experiments highlights the relevance of this new class of model compounds for broader use in catalysis studies. Only by understanding the reactivity of the linkages in lignin at this level of detail can fully optimized lignin depolymerization strategies be developed. PMID:27310182

  16. De novo assembly, transcriptome characterization, lignin accumulation, and anatomic characteristics: novel insights into lignin biosynthesis during celery leaf development

    PubMed Central

    Jia, Xiao-Ling; Wang, Guang-Long; Xiong, Fei; Yu, Xu-Run; Xu, Zhi-Sheng; Wang, Feng; Xiong, Ai-Sheng

    2015-01-01

    Celery of the family Apiaceae is a biennial herb that is cultivated and consumed worldwide. Lignin is essential for cell wall structural integrity, stem strength, water transport, mechanical support, and plant pathogen defense. This study discussed the mechanism of lignin formation at different stages of celery development. The transcriptome profile, lignin distribution, anatomical characteristics, and expression profile of leaves at three stages were analyzed. Regulating lignin synthesis in celery growth development has a significant economic value. Celery leaves at three stages were collected, and Illumina paired-end sequencing technology was used to analyze large-scale transcriptome sequences. From Stage 1 to 3, the collenchyma and vascular bundles in the petioles and leaf blades thickened and expanded, whereas the phloem and the xylem extensively developed. Spongy and palisade mesophyll tissues further developed and were tightly arranged. Lignin accumulation increased in the petioles and the mesophyll (palisade and spongy), and the xylem showed strong lignification. Lignin accumulation in different tissues and at different stages of celery development coincides with the anatomic characteristics and transcript levels of genes involved in lignin biosynthesis. Identifying the genes that encode lignin biosynthesis-related enzymes accompanied by lignin distribution may help elucidate the regulatory mechanisms of lignin biosynthesis in celery. PMID:25651889

  17. A facile method for processing lignin reinforced chitosan biopolymer microfibres: optimising the fibre mechanical properties through lignin type and concentration

    NASA Astrophysics Data System (ADS)

    Wang, K.; Loo, L. S.; Goh, K. L.

    2016-03-01

    A chitosan biopolymer microfibre—reinforced by lignin—has been processed by a wet-spinning method. To optimise the fibre mechanical and structural properties two types of lignin, with molecular weights 28 000 g mol-1 and 60 000 g mol-1, were examined and the chitosan fibre was blended with the respective lignin type at 1, 3, 5, 7 and 8 wt% lignin concentrations. The main effects of lignin type and concentration, as well as the interaction between the two parameters, on the fibre tensile stiffness, extensibility, strength and toughness were evaluated using the two-factor analysis of variance. Significant variations in the respective mechanical properties were observed with varying lignin concentrations (P < 0.05). The magnitude of the respective mechanical properties is low at 1 wt% but peaks at 3 wt% before decreasing steadily with increasing lignin concentration. Except for extensibility, significant variations in the strength and toughness were observed with respect to lignin type (P < 0.05) variations in the stiffness were masked by interactions between lignin type and concentration. These results were related to the dispersion of lignin in the fibre and the nature of the bonds between lignin and chitosan, based on findings from scanning electron microscopy and Fourier transform infrared spectroscopy. This new method for the fabrication of chitosan biopolymer microfibre is inexpensive and versatile and could lend itself to the production of high performance biocomposite structures.

  18. Lignin Fast Pyrolysis: Results from an International Collaboration

    SciTech Connect

    Nowakowski, Daniel J.; Bridgwater, Anthony V.; Elliott, Douglas C.; Meier, Dietrich; de Wild, Paul

    2010-05-01

    An international study of fast pyrolysis of lignin was undertaken. Fourteen laboratories in eight different countries contributed. Two lignin samples were distributed to the laboratories for analysis and bench-scale process testing in fast pyrolysis. Analyses included proximate and ultimate analysis, thermogravimetric analysis, and analytical pyrolysis. The bench-scale test included bubbling fluidized bed reactors and entrained flow systems. Based on the results of the various analyses and tests it was concluded that a concentrated lignin (estimated at about 50% lignin and 50% cellulose) behaved like a typical biomass, producing a slightly reduced amount of a fairly typical bio-oil, while a purified lignin material was difficult to process in the fast pyrolysis reactors and produced a much lower amount of a different kind of bio-oil. It was concluded that for highly concentrated lignin feedstocks new reactor designs will be required other than the typical fluidized bed fast pyrolysis systems.

  19. Directional synthesis of ethylbenzene through catalytic transformation of lignin.

    PubMed

    Fan, Minghui; Jiang, Peiwen; Bi, Peiyan; Deng, Shumei; Yan, Lifeng; Zhai, Qi; Wang, Tiejun; Li, Quanxin

    2013-09-01

    Transformation of lignin to ethylbenzene can provide an important bulk raw material for the petrochemical industry. This work explored the production of ethylbenzene from lignin through the directional catalytic depolymerization of lignin into the aromatic monomers followed by the selective alkylation of the aromatic monomers. For the first step, the aromatics selectivity of benzene derived from the catalytic depolymerization of lignin reached about 90.2 C-mol% over the composite catalyst of Re-Y/HZSM-5 (25). For the alkylation of the aromatic monomers in the second step, the highest selectivity of ethylbenzene was about 72.3 C-mol% over the HZSM-5 (25) catalyst. The reaction pathway for the transformation of lignin to ethylbenzene was also addressed. Present transformation potentially provides a useful approach for the production of the basic petrochemical material and development of high-end chemicals utilizing lignin as the abundant natural aromatic resource. PMID:23777846

  20. Mechanism of lignin inhibition of enzymatic biomass deconstruction

    SciTech Connect

    Vermaas, Josh V.; Petridis, Loukas; Qi, Xianghong; Schulz, Roland; Lindner, Benjamin; Smith, Jeremy. C.

    2015-12-01

    The conversion of plant biomass to ethanol via enzymatic cellulose hydrolysis offers a potentially sustainable route to biofuel production. However, the inhibition of enzymatic activity in pretreated biomass by lignin severely limits the efficiency of this process. By performing atomic-detail molecular dynamics simulation of a biomass model containing cellulose, lignin, and cellulases (TrCel7A), we elucidate detailed lignin inhibition mechanisms. We find that lignin binds preferentially both to the elements of cellulose to which the cellulases also preferentially bind (the hydrophobic faces) and also to the specific residues on the cellulose-binding module of the cellulase that are critical for cellulose binding of TrCel7A (Y466, Y492, and Y493). In conclusion, lignin thus binds exactly where for industrial purposes it is least desired, providing a simple explanation of why hydrolysis yields increase with lignin removal.

  1. Redistribution of Lignin Caused by Dilute Acid Pretreatment of Biomass

    SciTech Connect

    Johnson, D. K.; Donohoe, B. S.; Katahira, R.; Tucker, M. P.; Vinzant, T. B.; Himmel, M. E.

    2012-01-01

    Research conducted at NREL has shown that lignin undergoes a phase transition during thermochemical pretreatments conducted above its glass transition temperature. The lignin coalesces within the plant cell wall and appears as microscopic droplets on cell surfaces. It is clear that pretreatment causes significant changes in lignin distribution in pretreatments at all scales from small laboratory reactors to pilot scale reactors. A method for selectively extracting lignin droplets from the surfaces of pretreated cell walls has allowed us to characterize the chemical nature and molecular weight distribution of this fraction. The effect of lignin redistribution on the digestibility of pretreated solids has also been tested. It is clear that removal of the droplets increases the digestibility of pretreated corn stover. The improved digestibility could be due to decreased non-specific binding of enzymes to lignin in the droplets, or because the droplets no longer block access to cellulose.

  2. Mechanism of lignin inhibition of enzymatic biomass deconstruction

    DOE PAGESBeta

    Vermaas, Josh V.; Petridis, Loukas; Qi, Xianghong; Schulz, Roland; Lindner, Benjamin; Smith, Jeremy. C.

    2015-12-01

    The conversion of plant biomass to ethanol via enzymatic cellulose hydrolysis offers a potentially sustainable route to biofuel production. However, the inhibition of enzymatic activity in pretreated biomass by lignin severely limits the efficiency of this process. By performing atomic-detail molecular dynamics simulation of a biomass model containing cellulose, lignin, and cellulases (TrCel7A), we elucidate detailed lignin inhibition mechanisms. We find that lignin binds preferentially both to the elements of cellulose to which the cellulases also preferentially bind (the hydrophobic faces) and also to the specific residues on the cellulose-binding module of the cellulase that are critical for cellulose bindingmore » of TrCel7A (Y466, Y492, and Y493). In conclusion, lignin thus binds exactly where for industrial purposes it is least desired, providing a simple explanation of why hydrolysis yields increase with lignin removal.« less

  3. Comparison of lignin extraction processes: Economic and environmental assessment.

    PubMed

    Carvajal, Juan C; Gómez, Álvaro; Cardona, Carlos A

    2016-08-01

    This paper presents the technical-economic and environmental assessment of four lignin extraction processes from two different raw materials (sugarcane bagasse and rice husks). The processes are divided into two categories, the first processes evaluates lignin extraction with prior acid hydrolysis step, while in the second case the extraction processes are evaluated standalone for a total analysis of 16 scenarios. Profitability indicators as the net present value (NPV) and environmental indicators as the potential environmental impact (PEI) are used through a process engineering approach to understand and select the best lignin extraction process. The results show that both economically and environmentally process with sulfites and soda from rice husk presents the best results; however the quality of lignin obtained with sulfites is not suitable for high value-added products. Then, the soda is an interesting option for the extraction of lignin if high quality lignin is required for high value-added products at low costs. PMID:27174614

  4. Enzymatic synthesis of lignin-siloxane hybrid functional polymers.

    PubMed

    Prasetyo, Endry Nugroho; Kudanga, Tukayi; Fischer, Roman; Eichinger, Reinhard; Nyanhongo, Gibson S; Guebitz, Georg M

    2012-02-01

    This study combines the properties of siloxanes and lignin polymers to produce hybrid functional polymers that can be used as adhesives, coating materials, and/or multifunctionalized thin-coating films. Lignin-silica hybrid copolymers were synthesized by using a sol-gel process. Laccases from Trametes hirsuta were used to oxidize lignosulphonates to enhance their reactivity towards siloxanes and then were incorporated into siloxane precursors undergoing a sol-gel process. In vitro copolymerization studies using pure lignin monomers with aminosilanes or ethoxytrimethylsilane and analysis by ²⁹Si NMR spectroscopy revealed hybrid products. Except for kraft lignin, an increase in lignin concentration positively affected the tensile strength in all samples. Similarly, the viscosity generally increased in all samples with increasing lignin concentration and also affected the curing time. PMID:21751391

  5. Green Diesel from Kraft Lignin in Three Steps.

    PubMed

    Löfstedt, Joakim; Dahlstrand, Christian; Orebom, Alexander; Meuzelaar, Gerrit; Sawadjoon, Supaporn; Galkin, Maxim V; Agback, Peter; Wimby, Martin; Corresa, Elena; Mathieu, Yannick; Sauvanaud, Laurent; Eriksson, Sören; Corma, Avelino; Samec, Joseph S M

    2016-06-22

    Precipitated kraft lignin from black liquor was converted into green diesel in three steps. A mild Ni-catalyzed transfer hydrogenation/hydrogenolysis using 2-propanol generated a lignin residue in which the ethers, carbonyls, and olefins were reduced. An organocatalyzed esterification of the lignin residue with an in situ prepared tall oil fatty acid anhydride gave an esterified lignin residue that was soluble in light gas oil. The esterified lignin residue was coprocessed with light gas oil in a continous hydrotreater to produce a green diesel. This approach will enable the development of new techniques to process commercial lignin in existing oil refinery infrastructures to standardized transportation fuels in the future. PMID:27246391

  6. Ptr-miR397a is a negative regulator of laccase genes affecting lignin content in Populus trichocarpa

    PubMed Central

    Lu, Shanfa; Li, Quanzi; Wei, Hairong; Chang, Mao-Ju; Tunlaya-Anukit, Sermsawat; Kim, Hoon; Liu, Jie; Song, Jingyuan; Sun, Ying-Hsuan; Yuan, Lichai; Yeh, Ting-Feng; Peszlen, Ilona; Ralph, John; Sederoff, Ronald R.; Chiang, Vincent L.

    2013-01-01

    Laccases, as early as 1959, were proposed to catalyze the oxidative polymerization of monolignols. Genetic evidence in support of this hypothesis has been elusive due to functional redundancy of laccase genes. An Arabidopsis double mutant demonstrated the involvement of laccases in lignin biosynthesis. We previously identified a subset of laccase genes to be targets of a microRNA (miRNA) ptr-miR397a in Populus trichocarpa. To elucidate the roles of ptr-miR397a and its targets, we characterized the laccase gene family and identified 49 laccase gene models, of which 29 were predicted to be targets of ptr-miR397a. We overexpressed Ptr-MIR397a in transgenic P. trichocarpa. In each of all nine transgenic lines tested, 17 PtrLACs were down-regulated as analyzed by RNA-seq. Transgenic lines with severe reduction in the expression of these laccase genes resulted in an ∼40% decrease in the total laccase activity. Overexpression of Ptr-MIR397a in these transgenic lines also reduced lignin content, whereas levels of all monolignol biosynthetic gene transcripts remained unchanged. A hierarchical genetic regulatory network (GRN) built by a bottom-up graphic Gaussian model algorithm provides additional support for a role of ptr-miR397a as a negative regulator of laccases for lignin biosynthesis. Full transcriptome–based differential gene expression in the overexpressed transgenics and protein domain analyses implicate previously unidentified transcription factors and their targets in an extended hierarchical GRN including ptr-miR397a and laccases that coregulate lignin biosynthesis in wood formation. Ptr-miR397a, laccases, and other regulatory components of this network may provide additional strategies for genetic manipulation of lignin content. PMID:23754401

  7. Modeling lignin liquefaction: 1. Catalytic hydroprocessing of lignin-related methoxyphenols and interaromatic unit linkages

    SciTech Connect

    Petrocelli, F.P.; Klein, M.T.

    1987-01-01

    The reactions of two sets of lignin model compounds over a sulfided CoOMoO/sub 3//..gamma..-Al/sub 2/O/sub 3/ catalyst were studied. The first set mimicked lignin methoxyphenol residues and comprised 4-methyl-guaiacol, 4-methylcatechol, eugenol and vanillin. Deoxygenation and hydrogenation were facile and led to ultimate molar yields of single-ring products as high as 0.70. The selectivity to single-ring products increased with increases in temperature. o-hydroxydiphenylmethane, phenyl ether and o,o'-biphenol constituted the second set that mimicked thermally stable lignin bonds. Fragmentation of o-hydroxydiphenylmethane and phenyl ether occurred readily; o,o'-biphenol reacted to dibenzofuran.

  8. Evidence for lignin oxidation by the giant panda fecal microbiome.

    PubMed

    Fang, Wei; Fang, Zemin; Zhou, Peng; Chang, Fei; Hong, Yuzhi; Zhang, Xuecheng; Peng, Hui; Xiao, Yazhong

    2012-01-01

    The digestion of lignin and lignin-related phenolic compounds from bamboo by giant pandas has puzzled scientists because of the lack of lignin-degrading genes in the genome of the bamboo-feeding animals. We constructed a 16S rRNA gene library from the microorganisms derived from the giant panda feces to identify the possibility for the presence of potential lignin-degrading bacteria. Phylogenetic analysis showed that the phylotypes of the intestinal bacteria were affiliated with the phyla Proteobacteria (53%) and Firmicutes (47%). Two phylotypes were affiliated with the known lignin-degrading bacterium Pseudomonas putida and the mangrove forest bacteria. To test the hypothesis that microbes in the giant panda gut help degrade lignin, a metagenomic library of the intestinal bacteria was constructed and screened for clones that contained genes encoding laccase, a lignin-degrading related enzyme. A multicopper oxidase gene, designated as lac51, was identified from a metagenomic clone. Sequence analysis and copper content determination indicated that Lac51 is a laccase rather than a metallo-oxidase and may work outside its original host cell because it has a TAT-type signal peptide and a transmembrane segment at its N-terminus. Lac51 oxidizes a variety of lignin-related phenolic compounds, including syringaldazine, 2,6-dimethoxyphenol, ferulic acid, veratryl alcohol, guaiacol, and sinapinic acid at conditions that simulate the physiologic environment in giant panda intestines. Furthermore, in the presence of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), syringic acid, or ferulic acid as mediators, the oxidative ability of Lac51 on lignin was promoted. The absorbance of lignin at 445 nm decreased to 36% for ABTS, 51% for syringic acid, and 51% for ferulic acid after incubation for 10 h. Our findings demonstrate that the intestinal bacteria of giant pandas may facilitate the oxidation of lignin moieties, thereby clarifying the digestion of bamboo lignin

  9. Lignin transformations and reactivity upon ozonation in aqueous media

    NASA Astrophysics Data System (ADS)

    Khudoshin, A. G.; Mitrofanova, A. N.; Lunin, V. V.

    2012-03-01

    The reaction of ozone with lignin in aqueous acidic solutions is investigated. The Danckwerst model is used to describe the kinetics of gas/liquid processes occurring in a bubble reactor. The efficient ozonation rate of a soluble lignin analog, sodium lignosulfate, is determined. The main lines of the reaction between ozone and lignin are revealed on the basis of kinetic analysis results and IR and UV spectroscopy data.

  10. Evidence for Lignin Oxidation by the Giant Panda Fecal Microbiome

    PubMed Central

    Zhou, Peng; Chang, Fei; Hong, Yuzhi; Zhang, Xuecheng; Peng, Hui; Xiao, Yazhong

    2012-01-01

    The digestion of lignin and lignin-related phenolic compounds from bamboo by giant pandas has puzzled scientists because of the lack of lignin-degrading genes in the genome of the bamboo-feeding animals. We constructed a 16S rRNA gene library from the microorganisms derived from the giant panda feces to identify the possibility for the presence of potential lignin-degrading bacteria. Phylogenetic analysis showed that the phylotypes of the intestinal bacteria were affiliated with the phyla Proteobacteria (53%) and Firmicutes (47%). Two phylotypes were affiliated with the known lignin-degrading bacterium Pseudomonas putida and the mangrove forest bacteria. To test the hypothesis that microbes in the giant panda gut help degrade lignin, a metagenomic library of the intestinal bacteria was constructed and screened for clones that contained genes encoding laccase, a lignin-degrading related enzyme. A multicopper oxidase gene, designated as lac51, was identified from a metagenomic clone. Sequence analysis and copper content determination indicated that Lac51 is a laccase rather than a metallo-oxidase and may work outside its original host cell because it has a TAT-type signal peptide and a transmembrane segment at its N-terminus. Lac51 oxidizes a variety of lignin-related phenolic compounds, including syringaldazine, 2,6-dimethoxyphenol, ferulic acid, veratryl alcohol, guaiacol, and sinapinic acid at conditions that simulate the physiologic environment in giant panda intestines. Furthermore, in the presence of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), syringic acid, or ferulic acid as mediators, the oxidative ability of Lac51 on lignin was promoted. The absorbance of lignin at 445 nm decreased to 36% for ABTS, 51% for syringic acid, and 51% for ferulic acid after incubation for 10 h. Our findings demonstrate that the intestinal bacteria of giant pandas may facilitate the oxidation of lignin moieties, thereby clarifying the digestion of bamboo

  11. Isolation and characterization of lignins from Eucalyptus tereticornis (12ABL).

    PubMed

    Zhang, Aiping; Lu, Fachuang; Liu, Chuanfu; Sun, Run-Cang

    2010-11-10

    A three-step sequential extraction-precipitation method was used to isolate lignin from Eucalyptus tereticornis. The ball-milled eucalyptus was extracted with 96% dioxane, 50% dioxane, and 80% dioxane containing 1% NaOH at boiling temperature, consecutively resulting in solubilization of lignin and hemicelluloses. By precipitating such solutions into 70% aqueous ethanol, the hemicelluloses were removed substantially although there were still some carbohydrates left over, especially for lignin fraction extracted by 50% dioxane. Lignins dissolved in the 70% ethanol solutions were recovered via concentration and precipitation into acidified water. About 37% of the original lignin was released following such procedure whereas only 13.5% can be isolated by traditional milled wood lignin (MWL) method. The obtained lignin fractions were analyzed by high performance anion exchange chromatography (HPAEC) following acid hydrolysis for sugar composition of the contaminating carbohydrates and characterized by quantitative (31)P NMR as well as two-dimensional heteronuclear single-quantum coherence ((13)C-(1)H) NMR. The results showed that 96% aqueous dioxane extraction of ball-milled wood under conditions used in this study resulted in lignin preparation with very similar structures and sugar composition as traditional MWL. Therefore extracting ball-milled wood with 96% aqueous dioxane produced lignin in 33.6% yield, which makes it very attractive as an alternative to the traditional MWL method. However further extraction with 50% aqueous dioxane or 80% aqueous dioxane containing 1% NaOH gave just a little more lignins with different carbohydrate compositions from those in MWL. The eucalyptus lignins obtained were syringyl and guaiacyl type units. Lignin fraction obtained from 96% dioxane extraction was found to have more phenolic hydroxyl and less aliphatic hydroxyl than the other two preparations. PMID:20954709

  12. Acid precipitation and food quality: Effects of dietary Al, Ca and P on bone and liver characteristics in American black ducks and mallards

    USGS Publications Warehouse

    Sparling, D.W.

    1991-01-01

    American black ducks (Anas rubripes) and mallards (A. platyrhynchos) were fed diets varying in concentrations of aluminum (Al). calcium (Ca), and phosphorus (P) for 10 weeks to identify toxic effects of Al under conditions representative of areas with acid precipitation. Femur and liver tissues were analyzed for Al. Ca, and P concentrations and structural characteristics. At two weeks of age, both species demonstrated pronounced differences in femur Al and P concentrations and femur mass from dietary Al and interaction between Ca:P regimen and Al:Low Ca:Low P enhanced Al storage and decreased P and mass in femurs. Femur Ca was lowest in the Low Ca:Low P regimen but was not affected by dietary Al. At 10 weeks, femur and liver Al continued to vary with dietary Al. Elevated Al and reduced Ca lowered modulus of elasticity. Femur P increased with elevated dietary P in black ducks. Elevated dietary P negated some of the effects of dietary A! on femur mass in black ducks. Reduced Ca concentrations weakened bones of both species and lowered both Ca and P. An array of clinical signs including lameness, discoloration of the upper mandible, complete and greenstick fractures, and death were responses to elevated Al and Ca:P regimen. Black ducks seemed to display these signs over a wider range of diets than mallards. Diets of 1,000 mg/kg Al had toxic effects on both species, particularly when combined with diets low in Ca and P.

  13. Acid precipitation and food quality: Inhibition of growth and survival in black ducks and mallards by dietary aluminum, calcium and phosphorus

    USGS Publications Warehouse

    Robbins, C.S.

    1990-01-01

    In areas impacted by acid precipitation, water chemistry of acidic ponds and streams often changes, resulting in increased mobilization of aluminum and decreased concentration of calcium carbonate. Aluminum binds with phosphorus and inhibits its uptake by organisms. Thus, invertebrate food organisms used by waterfowl may have inadequate Ca and P or elevated Al for normal growth and development. Acid rain and its effects may be one of the factors negatively impacting American black ducks (Anas rubripes) in eastern North America. One-day old mallards (A. platyrhynchos) and black ducks were placed on one of three Ca:P regimens: low:low (LL), normal:normal (NN), and low:high (LH) with each regimen divided further into three or four Al levels for 10 weeks. Forty-five % of the black ducks died on nine different diets whereas only 28% of the mallards died on three different diets. Mortality was significantly related to diet in both species. Growth rates for body weight, culmens, wings, and tarsi of both species on control diets exceeded those on many treatment diets but the differences were less apparent for mallards than for black ducks. Differences among treatments were due to both Ca:P and Al levels.

  14. Effects of acidic precipitation on the water quality of streams in the Laurel Hill area, Somerset County, Pennsylvania, 1983-86

    USGS Publications Warehouse

    Barker, J.L.; Witt, E. C., III

    1990-01-01

    Five headwater streams in the Laurel Hill area in southwestern Pennsylvania were investigated from September 1983 through February 1986 to determine possible effects of acidic precipitation on water quality. Precipitation in the Laurel Hill area is among the most acidic in the Nation, with a mean volume-weighted pH of 4.06. Sulfate is the dominant acid-forming anion, averaging 3.6 milligrams per liter or about 50 kilograms per hectare in wet deposition alone. Nitrate averages about 2 milligrams per liter or 7 kilograms per hectare in the study area. Stream chemistry in the five streams is quite variable and apparently is influenced to a large degree by the bedrock geology and by small amounts of alkaline material in watershed soils. Three of the five streams with no or little acid-neutralizing capacity presently are devoid of fish because of low pH and elevated aluminum concentrations. Aluminum concentrations increase in the other two streams during rainfall and snowmelt despite comparatively higher base flow and acid-neutralizing capacities. Comparison of the chemistry of streamflow during 14 storm events at South Fork Bens Creek and North Fork Bens Creek reveals similar chemical responses when discharge suddenly increases. Concentrations of dissolved metals and sulfate increased during stormflow and snowmelt runoff, whereas concentrations of base cations, silica, and chloride decreased. Nitrate concentrations were not affected by rainfall runoff by tended to increase with snowmelt runoff.

  15. Selective conversion of biorefinery lignin into dicarboxylic acids.

    PubMed

    Ma, Ruoshui; Guo, Mond; Zhang, Xiao

    2014-02-01

    The emerging biomass-to-biofuel conversion industry has created an urgent need for identifying new applications for biorefinery lignin. This paper demonstrates a new route to producing dicarboxylic acids from biorefinery lignin through chalcopyrite-catalyzed oxidation in a highly selective process. Up to 95 % selectivity towards stable dicarboxylic acids was obtained for several types of biorefinery lignin and model compounds under mild, environmentally friendly reaction conditions. The findings from this study paved a new avenue to biorefinery lignin conversions and applications. PMID:24464928

  16. Experimental Study of Mechanistic Acid Deconstruction of Lignin

    SciTech Connect

    Sturgeon, M.; Kim, S.; Chmely, S. C.; Katahira, R.; Foust, T. D.; Beckham, G. T.

    2012-01-01

    Lignin is a major component of biomass, which remains highly underutilized in selective biomass conversion strategies to renewable fuels and chemicals. Here we are interested in studying the mechanisms related to the acid deconstruction of lignin with a combined theoretical and experimental approach. Quantum mechanical calculations were employed to elucidate possible deconstruction mechanisms with transition state theory. Model dimers, imitating H, S, and G lignins, were synthesized with the most abundant {beta} - O - 4 linkage in lignin. These compounds were then depolymerized using various acids and at different operating conditions. The deconstruction products were analyzed to complement the QM studies and investigate proposed mechanisms.

  17. In situ lignocellulosic unlocking mechanism for carbohydrate hydrolysis in termites: crucial lignin modification

    PubMed Central

    2011-01-01

    Background Termites are highly effective at degrading lignocelluloses, and thus can be used as a model for studying plant cell-wall degradation in biological systems. However, the process of lignin deconstruction and/or degradation in termites is still not well understood. Methods We investigated the associated structural modification caused by termites in the lignin biomolecular assembly in softwood tissues crucial for cell-wall degradation. We conducted comparative studies on the termite-digested (i.e. termite feces) and native (control) softwood tissues with the aid of advanced analytical techniques: 13C crosspolarization magic angle spinning and nuclear magnetic resonance (CP-MAS-NMR) spectroscopy, flash pyrolysis with gas chromatography mass spectrometry (Py-GC/MS), and Py-GC-MS in the presence of tetramethylammonium hydroxide (Py-TMAH)-GC/MS. Results The 13C CP/MAS NMR spectroscopic analysis revealed an increased level of guaiacyl-derived (G unit) polymeric framework in the termite-digested softwood (feces), while providing specific evidence of cellulose degradation. The Py-GC/MS data were in agreement with the 13C CP/MAS NMR spectroscopic studies, thus indicating dehydroxylation and modification of selective intermonomer side-chain linkages in the lignin in the termite feces. Moreover, Py-TMAH-GC/MS analysis showed significant differences in the product distribution between control and termite feces. This strongly suggests that the structural modification in lignin could be associated with the formation of additional condensed interunit linkages. Conclusion Collectively, these data further establish: 1) that the major β-O-4' (β-aryl ether) was conserved, albeit with substructure degeneracy, and 2) that the nature of the resulting polymer in termite feces retained most of its original aromatic moieties (G unit-derived). Overall, these results provide insight into lignin-unlocking mechanisms for understanding plant cell-wall deconstruction, which could be

  18. Polymeric Carbon Dioxide

    SciTech Connect

    Yoo, C-S.

    1999-11-02

    Synthesis of polymeric carbon dioxide has long been of interest to many chemists and materials scientists. Very recently we discovered the polymeric phase of carbon dioxide (called CO{sub 2}-V) at high pressures and temperatures. Our optical and x-ray results indicate that CO{sub 2}-V is optically non-linear, generating the second harmonic of Nd: YLF laser at 527 nm and is also likely superhard similar to cubic-boron nitride or diamond. CO{sub 2}-V is made of CO{sub 4} tetrahedra, analogous to SiO{sub 2} polymorphs, and is quenchable at ambient temperature at pressures above 1 GPa. In this paper, we describe the pressure-induced polymerization of carbon dioxide together with the stability, structure, and mechanical and optical properties of polymeric CO{sub 2}-V. We also present some implications of polymeric CO{sub 2} for high-pressure chemistry and new materials synthesis.

  19. Selective aerobic alcohol oxidation method for conversion of lignin into simple aromatic compounds

    DOEpatents

    Stahl, Shannon S; Rahimi, Alireza

    2015-03-03

    Described is a method to oxidize lignin or lignin sub-units. The method includes oxidation of secondary benzylic alcohol in the lignin or lignin sub-unit to a corresponding ketone in the presence of unprotected primarily aliphatic alcohol in the lignin or lignin sub-unit. The optimal catalyst system consists of HNO.sub.3 in combination with another Bronsted acid, in the absence of a metal-containing catalyst, thereby yielding a selectively oxidized lignin or lignin sub-unit. The method may be carried out in the presence or absence of additional reagents including TEMPO and TEMPO derivatives.

  20. Formic-acid-induced depolymerization of oxidized lignin to aromatics

    NASA Astrophysics Data System (ADS)

    Rahimi, Alireza; Ulbrich, Arne; Coon, Joshua J.; Stahl, Shannon S.

    2014-11-01

    Lignin is a heterogeneous aromatic biopolymer that accounts for nearly 30% of the organic carbon on Earth and is one of the few renewable sources of aromatic chemicals. As the most recalcitrant of the three components of lignocellulosic biomass (cellulose, hemicellulose and lignin), lignin has been treated as a waste product in the pulp and paper industry, where it is burned to supply energy and recover pulping chemicals in the operation of paper mills. Extraction of higher value from lignin is increasingly recognized as being crucial to the economic viability of integrated biorefineries. Depolymerization is an important starting point for many lignin valorization strategies, because it could generate valuable aromatic chemicals and/or provide a source of low-molecular-mass feedstocks suitable for downstream processing. Commercial precedents show that certain types of lignin (lignosulphonates) may be converted into vanillin and other marketable products, but new technologies are needed to enhance the lignin value chain. The complex, irregular structure of lignin complicates chemical conversion efforts, and known depolymerization methods typically afford ill-defined products in low yields (that is, less than 10-20wt%). Here we describe a method for the depolymerization of oxidized lignin under mild conditions in aqueous formic acid that results in more than 60wt% yield of low-molecular-mass aromatics. We present the discovery of this facile C-O cleavage method, its application to aspen lignin depolymerization, and mechanistic insights into the reaction. The broader implications of these results for lignin conversion and biomass refining are also considered.

  1. Redox Fluctuations Increase the Contribution of Lignin to Soil Respiration

    NASA Astrophysics Data System (ADS)

    Hall, S. J.; Silver, W. L.; Timokhin, V.; Hammel, K.

    2014-12-01

    Lignin mineralization represents a critical flux in the terrestrial carbon (C) cycle, yet little is known about mechanisms and environmental factors controlling lignin breakdown in mineral soils. Hypoxia has long been thought to suppress lignin decomposition, yet variation in oxygen (O2) availability in surface soils accompanying moisture fluctuations could potentially stimulate this process by generating reactive oxygen species via coupled biotic and abiotic iron (Fe) redox cycling. Here, we tested the impact of redox fluctuations on lignin breakdown in humid tropical forest soils during ten-week laboratory incubations. We used synthetic lignins labeled with 13C in either of two positions (aromatic methoxyl and propyl Cβ) to provide highly sensitive and specific measures of lignin mineralization not previously employed in soils. Four-day redox fluctuations increased the percent contribution of methoxyl C to soil respiration, and cumulative methoxyl C mineralization was equivalent under static aerobic and fluctuating redox conditions despite lower total C mineralization in the latter treatment. Contributions of the highly stable Cβ to mineralization were also equivalent in static aerobic and fluctuating redox treatments during periods of O2 exposure, and nearly doubled in the fluctuating treatment after normalizing to cumulative O2 exposure. Oxygen fluctuations drove substantial net Fe reduction and oxidation, implying that reactive oxygen species generated during abiotic Fe oxidation likely contributed to the elevated contribution of lignin to C mineralization. Iron redox cycling provides a mechanism for lignin breakdown in soils that experience conditions unfavorable for canonical lignin-degrading organisms, and provides a potential mechanism for lignin depletion in soil organic matter during late-stage decomposition. Thus, close couplings between soil moisture, redox fluctuations, and lignin breakdown provide potential a link between climate variability and

  2. Formic-acid-induced depolymerization of oxidized lignin to aromatics.

    PubMed

    Rahimi, Alireza; Ulbrich, Arne; Coon, Joshua J; Stahl, Shannon S

    2014-11-13

    Lignin is a heterogeneous aromatic biopolymer that accounts for nearly 30% of the organic carbon on Earth and is one of the few renewable sources of aromatic chemicals. As the most recalcitrant of the three components of lignocellulosic biomass (cellulose, hemicellulose and lignin), lignin has been treated as a waste product in the pulp and paper industry, where it is burned to supply energy and recover pulping chemicals in the operation of paper mills. Extraction of higher value from lignin is increasingly recognized as being crucial to the economic viability of integrated biorefineries. Depolymerization is an important starting point for many lignin valorization strategies, because it could generate valuable aromatic chemicals and/or provide a source of low-molecular-mass feedstocks suitable for downstream processing. Commercial precedents show that certain types of lignin (lignosulphonates) may be converted into vanillin and other marketable products, but new technologies are needed to enhance the lignin value chain. The complex, irregular structure of lignin complicates chemical conversion efforts, and known depolymerization methods typically afford ill-defined products in low yields (that is, less than 10-20wt%). Here we describe a method for the depolymerization of oxidized lignin under mild conditions in aqueous formic acid that results in more than 60wt% yield of low-molecular-mass aromatics. We present the discovery of this facile C-O cleavage method, its application to aspen lignin depolymerization, and mechanistic insights into the reaction. The broader implications of these results for lignin conversion and biomass refining are also considered. PMID:25363781

  3. Acid precipitation; an annotated bibliography

    USGS Publications Warehouse

    Wiltshire, Denise A.; Evans, Margaret L.

    1984-01-01

    This collection of 1660 bibliographies references on the causes and environmental effects of acidic atmospheric deposition was compiled from computerized literature searches of earth-science and chemistry data bases. Categories of information are (1) atmospheric chemistry (gases and aerosols), (2) precipitation chemistry, (3) transport and deposition (wet and dry), (4) aquatic environments (biological and hydrological), (5) terrestrial environments, (6) effects on materials and structures, (7) air and precipitation monitoring and data collection, and (8) modeling studies. References date from the late 1800 's through December 1981. The bibliography includes short summaries of most documents. Omitted are unpublished manuscripts, publications in press, master 's theses and doctoral dissertations, newspaper articles, and book reviews. Coauthors and subject indexes are included. (USGS)

  4. Biomass conversion: Lignin up for break-down

    NASA Astrophysics Data System (ADS)

    Bruijnincx, Pieter C. A.; Weckhuysen, Bert M.

    2014-12-01

    Lignin is an abundant renewable resource, but its intrinsic recalcitrant nature has so far hampered its conversion into higher value chemicals. Now, a two-step strategy, oxidation followed by bond cleavage, has been shown to deconstruct lignin into high yields of low-molecular-weight aromatics.

  5. Metabolic engineering of novel lignin in biomass crops.

    PubMed

    Vanholme, Ruben; Morreel, Kris; Darrah, Chiarina; Oyarce, Paula; Grabber, John H; Ralph, John; Boerjan, Wout

    2012-12-01

    Lignin, a phenolic polymer in the secondary wall, is the major cause of lignocellulosic biomass recalcitrance to efficient industrial processing. From an applications perspective, it is desirable that second-generation bioenergy crops have lignin that is readily degraded by chemical pretreatments but still fulfill its biological role in plants. Because plants can tolerate large variations in lignin composition, often without apparent adverse effects, substitution of some fraction of the traditional monolignols by alternative monomers through genetic engineering is a promising strategy to tailor lignin in bioenergy crops. However, successful engineering of lignin incorporating alternative monomers requires knowledge about phenolic metabolism in plants and about the coupling properties of these alternative monomers. Here, we review the current knowledge about lignin biosynthesis and the pathways towards the main phenolic classes. In addition, the minimal requirements are defined for molecules that, upon incorporation into the lignin polymer, make the latter more susceptible to biomass pretreatment. Numerous metabolites made by plants meet these requirements, and several have already been tested as monolignol substitutes in biomimetic systems. Finally, the status of detection and identification of compounds by phenolic profiling is discussed, as phenolic profiling serves in pathway elucidation and for the detection of incorporation of alternative lignin monomers. PMID:23035778

  6. The effect of dietary psyllium hydrocolloid and lignin on bile.

    PubMed

    Brydon, W G; Borup-Christensen, S; Van der Linden, W; Eastwood, M A

    1979-07-01

    Animal experiments suggest that supplementing the diet with either psyllium seed husk or lignin alters the ratio of deoxycholic acid to chenodeoxycholic in bile. In this study dosages of psyllium seed husk or lignin acceptable to patients with gallstones do not appear to alter the relative amounts of cholesterol, or individual bile acids in the bile. PMID:524929

  7. Metabolic engineering of novel lignin in biomass crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lignin, a phenolic polymer in the secondary-thickened plant cell wall, is the major cause of lignocellulosic biomass recalcitrance toward efficient industrial processing. From an applications perspective, it is desirable that secondary cell walls of second generation bioenergy crops have lignin that...

  8. THERMOPLASTIC STARCH-KRAFT LIGNIN-GLYCEROL BLENDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch-kraft lignin-glycerol blends were extruded in a twin-screw extruder to produce non-brittle films. One week after extrusion, films with a mid-range composition of 52% starch, 20% lignin, and 28% glycerol showed a tensile strength at break of 2.8 MPa, Young's modulus of 48 MPa, and elongation ...

  9. [Characterization of lignin and Mn peroxidases from Phanerochaete chrysosporium

    SciTech Connect

    Not Available

    1992-01-01

    Lignin peroxidases were investigated with respect to enzyme kinetics and NMR spectroscopy of the heme domain. MN peroxidases were studied with respect to the role of oxalate in enzyme activity, the NMR spectroscopy of the heme domain. Gene expression of both lignin and MN peroxidases were examined as well as expression of site-directed mutants aimed at scale up production of these enzymes.

  10. Lignin Degradation by Fusarium solani f. sp. glycines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sudden death syndrome (SDS), caused by the soilborne fungal pathogen Fusarium solani f. sp. glycines, is one of the most important diseases of soybean. Lignin degradation may play a role in the infection, colonization, and survival of the fungus in root tissue . Lignin degradation by F. solani f. sp...

  11. Roles of lignin biosynthesis and regulatory genes in plant development.

    PubMed

    Yoon, Jinmi; Choi, Heebak; An, Gynheung

    2015-11-01

    Lignin is an important factor affecting agricultural traits, biofuel production, and the pulping industry. Most lignin biosynthesis genes and their regulatory genes are expressed mainly in the vascular bundles of stems and leaves, preferentially in tissues undergoing lignification. Other genes are poorly expressed during normal stages of development, but are strongly induced by abiotic or biotic stresses. Some are expressed in non-lignifying tissues such as the shoot apical meristem. Alterations in lignin levels affect plant development. Suppression of lignin biosynthesis genes causes abnormal phenotypes such as collapsed xylem, bending stems, and growth retardation. The loss of expression by genes that function early in the lignin biosynthesis pathway results in more severe developmental phenotypes when compared with plants that have mutations in later genes. Defective lignin deposition is also associated with phenotypes of seed shattering or brittle culm. MYB and NAC transcriptional factors function as switches, and some homeobox proteins negatively control lignin biosynthesis genes. Ectopic deposition caused by overexpression of lignin biosynthesis genes or master switch genes induces curly leaf formation and dwarfism. PMID:26297385

  12. Modification of lignin content and composition in plants

    DOEpatents

    Ye, Zheng-Hua

    2002-01-01

    Plants and methods of preparing plants having reduced lignin content and/or altered lignin composition are provided. The activities of caffeoyl-CoA O-methyltransferase and/or caffeic acid O-methyltransferase enzymes in the modified plants are reduced.

  13. THE PROPERTIES OF SYRINGYL, GUAIACYL AND P-HYDROXYPHENYL ARTIFICIAL LIGNINS.

    PubMed

    BLAND, D E; LOGAN, A F

    1965-05-01

    1. Artificial lignins have been produced on potato parenchyma. 2. The methoxyl-free lignin and 4-hydroxy-3-methoxy (guaiacyl) lignins could be estimated by the sulphuric acid method but the 4-hydroxy-3,5-dimethoxy (syringyl) lignins could not. 3. Permanganate oxidation of isolated p-coumaric lignin gave 4-hydroxybenzoic acid, 4-hydroxyisophthalic acid and small amounts of hydroxytrimesic acid and 4-hydroxyphthalic acid. Ferulic lignin gave vanillic acid and 5-carboxyvanillic acid and also small amounts of 4-hydroxybenzoic acid and dehydrodivanillic acid. The sinapic lignin gave traces of syringic acid and of 4-hydroxybenzoic acid. 4. The p-coumaric lignin is a highly condensed polymer. The ferulic lignin is partly uncondensed and partly condensed through the 5-position like gymnosperm lignin. The sinapic lignin shows no evidence of condensation and is probably an ether-linked polymer. PMID:14340102

  14. Paving the Way for Lignin Valorisation: Recent Advances in Bioengineering, Biorefining and Catalysis.

    PubMed

    Rinaldi, Roberto; Jastrzebski, Robin; Clough, Matthew T; Ralph, John; Kennema, Marco; Bruijnincx, Pieter C A; Weckhuysen, Bert M

    2016-07-11

    Lignin is an abundant biopolymer with a high carbon content and high aromaticity. Despite its potential as a raw material for the fuel and chemical industries, lignin remains the most poorly utilised of the lignocellulosic biopolymers. Effective valorisation of lignin requires careful fine-tuning of multiple "upstream" (i.e., lignin bioengineering, lignin isolation and "early-stage catalytic conversion of lignin") and "downstream" (i.e., lignin depolymerisation and upgrading) process stages, demanding input and understanding from a broad array of scientific disciplines. This review provides a "beginning-to-end" analysis of the recent advances reported in lignin valorisation. Particular emphasis is placed on the improved understanding of lignin's biosynthesis and structure, differences in structure and chemical bonding between native and technical lignins, emerging catalytic valorisation strategies, and the relationships between lignin structure and catalyst performance. PMID:27311348

  15. The properties of syringyl, guaiacyl and p-hydroxyphenyl artificial lignins

    PubMed Central

    Bland, D. E.; Logan, A. F.

    1965-01-01

    1. Artificial lignins have been produced on potato parenchyma. 2. The methoxyl-free lignin and 4-hydroxy-3-methoxy (guaiacyl) lignins could be estimated by the sulphuric acid method but the 4-hydroxy-3,5-dimethoxy (syringyl) lignins could not. 3. Permanganate oxidation of isolated p-coumaric lignin gave 4-hydroxybenzoic acid, 4-hydroxyisophthalic acid and small amounts of hydroxytrimesic acid and 4-hydroxyphthalic acid. Ferulic lignin gave vanillic acid and 5-carboxyvanillic acid and also small amounts of 4-hydroxybenzoic acid and dehydrodivanillic acid. The sinapic lignin gave traces of syringic acid and of 4-hydroxybenzoic acid. 4. The p-coumaric lignin is a highly condensed polymer. The ferulic lignin is partly uncondensed and partly condensed through the 5-position like gymnosperm lignin. The sinapic lignin shows no evidence of condensation and is probably an ether-linked polymer. PMID:14340102

  16. Lignin model compounds as bio-based reactive diluents for liquid molding resins.

    PubMed

    Stanzione, Joseph F; Sadler, Joshua M; La Scala, John J; Wool, Richard P

    2012-07-01

    Lignin is a copious paper and pulping waste product that has the potential to yield valuable, low molecular weight, single aromatic chemicals when strategically depolymerized. The single aromatic lignin model compounds, vanillin, guaiacol, and eugenol, were methacrylated by esterification with methacrylic anhydride and a catalytic amount of 4-dimethylaminopyridine. Methacrylated guaiacol (MG) and methacrylated eugenol (ME) exhibited low viscosities at room temperature (MG: 17 cP and ME: 28 cP). When used as reactive diluents in vinyl ester resins, they produced resin viscosities higher than that of vinyl ester-styrene blends. The relative volatilities of MG (1.05 wt% loss in 18 h) and ME (0.96 wt% loss in 18 h) measured by means of thermogravimetric analysis (TGA) were considerably lower than that of styrene (93.7 wt% loss in 3 h) indicating the potential of these chemicals to be environmentally friendly reactive diluents. Bulk polymerization of MG and ME generated homopolymers with glass transition temperatures (T(g)s) of 92 and 103 °C, respectively. Blends of a standard vinyl ester resin with MG and ME (50 wt % reactive diluent) produced thermosets with T(g)s of 127 and 153 °C, respectively, which are comparable to vinyl ester-styrene resins, thus demonstrating the ability of MG and ME to completely replace styrene as reactive diluents in liquid molding resins without sacrificing cured-resin thermal performance. PMID:22517580

  17. Lignin depolymerisation strategies: towards valuable chemicals and fuels.

    PubMed

    Xu, Chunping; Arancon, Rick Arneil D; Labidi, Jalel; Luque, Rafael

    2014-11-21

    Research on lignin deconstruction has recently become the center of interest for scientists and companies worldwide, racing towards harvesting fossil-fuel like aromatic compounds which are so durably put together by plants as products of millions of years of evolution. The natural complexity and high stability of lignin bonds (also as an evolutionary adaptation by plants) makes lignin depolymerization a highly challenging task. Several efforts have been directed towards a more profound understanding of the structure and composition of lignin in order to devise pathways to break down the biopolymer into useful compounds. The present contribution aims to provide an overview of key advances in the field of lignin depolymerisation. Protocols and technologies will be discussed as well as critically evaluated in terms of possibilities and potential for further industrial implementation. PMID:25287249

  18. Catalytic Hydrolytic Cleavage and Oxy-Cleavage of Lignin Linkages

    SciTech Connect

    Xia, Guanguang; Chen, Baowei; Zhang, Rui; Zhang, Z. Conrad

    2014-07-26

    In this work, new strategies involving organic bases were evaluated to depolymerize lignin to reduced molecular fragments in aqueous medium. NaOH as an inorganic base was also investigated as a reference. Full nature lignin samples are used for the study. As research tools to unravel the complexity of the macro lignin structure and bulky molecular size under this study, size exclusion chromatography and high resolution mass spectrometric analysis, typically used for protein characterizations, were used to follow the progress of lignin depolymerisation by measuring the molecular weight distribution of the products and determining the key molecular fingerprints, respectively. The results show that sodium phenoxide and guanidine carbonate are effective catalysts for lignin depolymerization. It is observed that there exists a synergism between H2O2 and the organic base, which is strongest with guanidine carbonate.

  19. Process for conversion of lignin to reformulated hydrocarbon gasoline

    DOEpatents

    Shabtai, Joseph S.; Zmierczak, Wlodzimierz W.; Chornet, Esteban

    1999-09-28

    A process for converting lignin into high-quality reformulated hydrocarbon gasoline compositions in high yields is disclosed. The process is a two-stage, catalytic reaction process that produces a reformulated hydrocarbon gasoline product with a controlled amount of aromatics. In the first stage, a lignin material is subjected to a base-catalyzed depolymerization reaction in the presence of a supercritical alcohol as a reaction medium, to thereby produce a depolymerized lignin product. In the second stage, the depolymerized lignin product is subjected to a sequential two-step hydroprocessing reaction to produce a reformulated hydrocarbon gasoline product. In the first hydroprocessing step, the depolymerized lignin is contacted with a hydrodeoxygenation catalyst to produce a hydrodeoxygenated intermediate product. In the second hydroprocessing step, the hydrodeoxygenated intermediate product is contacted with a hydrocracking/ring hydrogenation catalyst to produce the reformulated hydrocarbon gasoline product which includes various desirable naphthenic and paraffinic compounds.

  20. Lignin biodegradation and the production of ethyl alcohol from cellulose

    SciTech Connect

    Rosenberg, S.L.; Wilke, C.R.

    1981-02-01

    During the last few years our group has been engaged in developing a biochemical process for the conversion of lignocellulosic materials to ethyl alcohol. Lignin is a barrier to complete cellulose saccharification in this process, but chemical and physical delignification steps are too expensive to be used at the present time. An enzymatic delignification process might be attractive for several reasons: little energy would be expected to be needed, enzymes could be recovered and reused, and useful chemicals might be produced from dissolved lignin. A number of thermophilic and thermotolerant fungi were examined for the ability to rapidly degrade lignocellulose in order to find an organism whcih produced an active lignin-degrading enzyme system. Chryosporium pruinosum and Sporotrichum pulverulentum were found to be active lignocellulose degraders, and C. pruinosum was chosen for further study. Lignin and carbohydrate were degraded when the substrate remained moistened by, but not submerged in, the liquid medium. Attempts were made to demonstrate a cell-free lignin degrading system by both extraction and pressing of cultures grown on moist lignocellulose. Carbohydrate-degrading activity was found but not lignin-degrading activity. This led us to ask whether diffusible lignin-degrading activity could be demonstrated in this organism. The data indicate that the lignin degradation system, or one or more of its components, produced by this organism is either unstable, non-diffusible, or inactive at small distances (about 1 mm) from growing hyphae. At present, studies are being conducted using diffusion cultures to select mutants of C. pruinosum that do produce a diffusible lignin degradation system. We are also examining a number of mesophilic lignin-degrading molds for this ability.

  1. ATP-binding cassette-like transporters are involved in the transport of lignin precursors across plasma and vacuolar membranes

    SciTech Connect

    Miao, Y.C.; Liu, C.

    2010-12-28

    Lignin is a complex biopolymer derived primarily from the condensation of three monomeric precursors, the monolignols. The synthesis of monolignols occurs in the cytoplasm. To reach the cell wall where they are oxidized and polymerized, they must be transported across the cell membrane. However, the molecular mechanisms underlying the transport process are unclear. There are conflicting views about whether the transport of these precursors occurs by passive diffusion or is an energized active process; further, we know little about what chemical forms are required. Using isolated plasma and vacuolar membrane vesicles prepared from Arabidopsis, together with applying different transporter inhibitors in the assays, we examined the uptake of monolignols and their derivatives by these native membrane vesicles. We demonstrate that the transport of lignin precursors across plasmalemma and their sequestration into vacuoles are ATP-dependent primary-transport processes, involving ATP-binding cassette-like transporters. Moreover, we show that both plasma and vacuolar membrane vesicles selectively transport different forms of lignin precursors. In the presence of ATP, the inverted plasma membrane vesicles preferentially take up monolignol aglycones, whereas the vacuolar vesicles are more specific for glucoconjugates, suggesting that the different ATP-binding cassette-like transporters recognize different chemical forms in conveying them to distinct sites, and that glucosylation of monolignols is necessary for their vacuolar storage but not required for direct transport into the cell wall in Arabidopsis.

  2. Cell wall fermentation kinetics are impacted more by lignin content and ferulate cross-linking than by lignin composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    BACKGROUND: We used a biomimetic model system to ascertain how reductions in ferulate-lignin cross-linking and shifts in lignin composition influence ruminal cell wall fermentation. Primary walls from maize cell suspensions with normal or reduced feruloylation were artificially lignified with variou...

  3. Structure-property characteristics of pyrolytic lignins derived from fast pyrolysis of a lignin rich biomass extract

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, various fractions of pyrolytic lignin were isolated from the fast pyrolysis oil of Etek lignin, a residue of acidic processing of wood. Based on the solubility differences in selected solvents, the water insolubles of the pyrolysis oil were separated into various fractions (methanol-i...

  4. Polymerization catalyst system

    SciTech Connect

    Graves, V.

    1986-03-25

    This patent describes a catalyst system for polymerizing at least one alpha-olefin under conditions characteristic of Ziegler polymerization. This system consists of: 1. a supported polymerization catalyst or mixture of polymerization catalysts prepared under anhydrous conditions by the sequential steps of: (a) preparing a slurry of inert particulate porous support material; (b) adding to the slurry a solution of an organomagnesium compound; (c) adding to the slurry and reacting a solution of a zirconium halide compound, hafnium compound or mixtures thereof; (d) adding to the slurry and reacting a halogenator; (e) adding to the slurry and reacting a tetravalent titanium halide compound; and (f) recovering solid catalyst component; 2. an organoaluminum compound; and 3. a promotor of chlorinated hydrocarbons having one to 20 carbon atoms.

  5. Expression of SofLAC, a new laccase in sugarcane, restores lignin content but not S:G ratio of Arabidopsis lac17 mutant.

    PubMed

    Cesarino, Igor; Araújo, Pedro; Sampaio Mayer, Juliana Lischka; Vicentini, Renato; Berthet, Serge; Demedts, Brecht; Vanholme, Bartel; Boerjan, Wout; Mazzafera, Paulo

    2013-04-01

    Lignin is a complex phenolic heteropolymer deposited in the secondarily thickened walls of specialized plant cells to provide strength for plants to stand upright and hydrophobicity to conducting cells for long-distance water transport. Although essential for plant growth and development, lignin is the major plant cell-wall component responsible for biomass recalcitrance to industrial processing. Peroxidases and laccases are generally thought to be responsible for lignin polymerization, but, given their broad substrate specificities and large gene families, specific isoforms involved in lignification are difficult to identify. This study used a combination of co-expression analysis, tissue/cell-type-specific expression analysis, and genetic complementation to correlate a sugarcane laccase gene, SofLAC, to the lignification process. A co-expression network constructed from 37 cDNA libraries showed that SofLAC was coordinately expressed with several phenylpropanoid biosynthesis genes. Tissue-specific expression analysis by quantitative RT-PCR showed that SofLAC was expressed preferentially in young internodes and that expression levels decrease with stem maturity. Cell-type-specific expression analysis by in situ hybridization demonstrated the localization of SofLAC mRNA in lignifying cell types, mainly in inner and outer portions of sclerenchymatic bundle sheaths. To investigate whether SofLAC is able to oxidize monolignols during lignification, the Arabidopsis lac17 mutant, which has reduced lignin levels, was complemented by expressing SofLAC under the control of the Arabidopsis AtLAC17 promoter. The expression of SofLAC restored the lignin content but not the lignin composition in complemented lac17 mutant lines. Taken together, these results suggest that SofLAC participates in lignification in sugarcane. PMID:23418623

  6. Radical-Mediated Enzymatic Polymerizations

    PubMed Central

    Zavada, Scott R.; Battsengel, Tsatsral; Scott, Timothy F.

    2016-01-01

    Polymerization reactions are commonly effected by exposing monomer formulations to some initiation stimulus such as elevated temperature, light, or a chemical reactant. Increasingly, these polymerization reactions are mediated by enzymes―catalytic proteins―owing to their reaction efficiency under mild conditions as well as their environmental friendliness. The utilization of enzymes, particularly oxidases and peroxidases, for generating radicals via reduction-oxidation mechanisms is especially common for initiating radical-mediated polymerization reactions, including vinyl chain-growth polymerization, atom transfer radical polymerization, thiol–ene step-growth polymerization, and polymerization via oxidative coupling. While enzyme-mediated polymerization is useful for the production of materials intended for subsequent use, it is especially well-suited for in situ polymerizations, where the polymer is formed in the place where it will be utilized. Such polymerizations are especially useful for biomedical adhesives and for sensing applications. PMID:26848652

  7. Radical-Mediated Enzymatic Polymerizations.

    PubMed

    Zavada, Scott R; Battsengel, Tsatsral; Scott, Timothy F

    2016-01-01

    Polymerization reactions are commonly effected by exposing monomer formulations to some initiation stimulus such as elevated temperature, light, or a chemical reactant. Increasingly, these polymerization reactions are mediated by enzymes--catalytic proteins--owing to their reaction efficiency under mild conditions as well as their environmental friendliness. The utilization of enzymes, particularly oxidases and peroxidases, for generating radicals via reduction-oxidation mechanisms is especially common for initiating radical-mediated polymerization reactions, including vinyl chain-growth polymerization, atom transfer radical polymerization, thiol-ene step-growth polymerization, and polymerization via oxidative coupling. While enzyme-mediated polymerization is useful for the production of materials intended for subsequent use, it is especially well-suited for in situ polymerizations, where the polymer is formed in the place where it will be utilized. Such polymerizations are especially useful for biomedical adhesives and for sensing applications. PMID:26848652

  8. [Isolation, identification of lignin-degrading bacteria and purification of lignin peroxidase].

    PubMed

    Yang, Jin-shui; Liu, Wei; Ni, Jin-ren

    2006-05-01

    Two strains that could use lignin as sole carbon source and excrete peroxidases were isolated from activated sludge. Both strains are belonged to Pseudomanas based on morphological, physio-biochenical characterizatics and homology identification of 16S rDNA sequence, in which strain PKE117 is identified as a new species, while the strain PKE225 is identified as Pseudomanas thermaerum. Crude enzyme in liquid fermentation of PKE117 was analyzed with DEAE-cellulose 32 ion-exchanger resin chromatography and Sephadex G-75 gel-filtration in proper order. The lignin peroxidase specific activity increases from 0.87 U/mg to 204.5 U/mg, purification multiple is 235.1 and callback rate is 15%. PMID:16850845

  9. Producing a True Lignin Depolymerase for Biobleaching Softwood Kraft Pulp

    SciTech Connect

    Simo Sarkanen

    2002-02-04

    This project constituted an intensive effort devoted to producing, from the white-rot fungus Tramets Cingulata, a lignin degrading enzyme (lignin depolymerase) that is directly able to biobleach or delignify softwood kraft pulp brownstock. To this end, the solutions in which T. cingulata was grown contained dissolved kraft lignin which fulfilled two functions; it behaved as a lignin deploymerase substrate and it also appeared to act as an inducer of enzyme expression. However, the lignin depolymerase isoenzymes (and other extracellular T. cingulata enzymes) interacted very strongly with both the kraft lignin components and the fungal hypae, so the isolating these proteins from the culture solutions proved to be unexpectedly difficult. Even after extensive experimentation with a variety of protein purification techniques, only one approach appeared to be capable of purifying lignin depolymerases to homogeneity. Unfortunately the procedure was extremely laborious; it involved the iso electric focusing of concentrated buffer-exchanged culture solutions followed by electro-elution of the desired protein bands from the appropriate polyacrylamide gel segments

  10. Azo dye biodecolorization enhanced by Echinodontium taxodii cultured with lignin.

    PubMed

    Han, Yuling; Shi, Lili; Meng, Jing; Yu, Hongbo; Zhang, Xiaoyu

    2014-01-01

    Lignocellulose facilitates the fungal oxidization of recalcitrant organic pollutants through the extracellular ligninolytic enzymes induced by lignin in wood or other plant tissues. However, available information on this phenomenon is insufficient. Free radical chain reactions during lignin metabolism are important in xenobiotic removal. Thus, the effect of lignin on azo dye decolorization in vivo by Echinodontium taxodii was evaluated. In the presence of lignin, optimum decolorization percentages for Remazol Brilliant Violet 5R, Direct Red 5B, Direct Black 38, and Direct Black 22 were 91.75% (control, 65.96%), 76.89% (control, 43.78%), 43.44% (control, 17.02%), and 44.75% (control, 12.16%), respectively, in the submerged cultures. Laccase was the most important enzyme during biodecolorization. Aside from the stimulating of laccase activity, lignin might be degraded by E. taxodii, and then these degraded low-molecular-weight metabolites could act as redox mediators promoting decolorization of azo dyes. The relationship between laccase and lignin degradation was investigated through decolorization tests in vitro with purified enzyme and dozens of aromatics, which can be derivatives of lignin and can function as laccase mediators or inducers. Dyes were decolorized at triple or even higher rates in certain laccase-aromatic systems at chemical concentrations as low as 10 µM. PMID:25285777

  11. Azo Dye Biodecolorization Enhanced by Echinodontium taxodii Cultured with Lignin

    PubMed Central

    Meng, Jing; Yu, Hongbo; Zhang, Xiaoyu

    2014-01-01

    Lignocellulose facilitates the fungal oxidization of recalcitrant organic pollutants through the extracellular ligninolytic enzymes induced by lignin in wood or other plant tissues. However, available information on this phenomenon is insufficient. Free radical chain reactions during lignin metabolism are important in xenobiotic removal. Thus, the effect of lignin on azo dye decolorization in vivo by Echinodontium taxodii was evaluated. In the presence of lignin, optimum decolorization percentages for Remazol Brilliant Violet 5R, Direct Red 5B, Direct Black 38, and Direct Black 22 were 91.75% (control, 65.96%), 76.89% (control, 43.78%), 43.44% (control, 17.02%), and 44.75% (control, 12.16%), respectively, in the submerged cultures. Laccase was the most important enzyme during biodecolorization. Aside from the stimulating of laccase activity, lignin might be degraded by E. taxodii, and then these degraded low-molecular-weight metabolites could act as redox mediators promoting decolorization of azo dyes. The relationship between laccase and lignin degradation was investigated through decolorization tests in vitro with purified enzyme and dozens of aromatics, which can be derivatives of lignin and can function as laccase mediators or inducers. Dyes were decolorized at triple or even higher rates in certain laccase–aromatic systems at chemical concentrations as low as 10 µM. PMID:25285777

  12. Recent advances in green hydrogels from lignin: a review.

    PubMed

    Thakur, Vijay Kumar; Thakur, Manju Kumari

    2015-01-01

    Recently, biorenewable polymers from different natural resources have attracted a greater attention of the research community for different applications starting from biomedical to automotive. Lignin is the second most abundant non-food biomass next to cellulose in the category of biorenewable polymers and is abundantly available as byproduct of several industries involved in paper making, ethanol production, etc. The development of various green materials from lignin, which is most often considered as waste, is therefore of prime interest from environmental and economic points of view. Over the last few years, little studies have been made into the use of lignin as an indispensable component in the hydrogels. This article provides an overview of the research work carried out in the last few years on lignin based hydrogels. This article comprehensively reviews the potential efficacy of lignin in biopolymer based green hydrogels with particular emphasis on synthesis, characterization and applications. In this article, several examples of hydrogels synthesized using different types of lignin are discussed to illustrate the state of the art in the use of lignin. PMID:25304747

  13. Oxidation in Acidic Medium of Lignins from Agricultural Residues

    NASA Astrophysics Data System (ADS)

    Labat, Gisele Aparecida Amaral; Gonçalves, Adilson Roberto

    Agricultural residues as sugarcane straw and bagasse are burned in boilers for generation of energy in sugar and alcohol industries. However, excess of those by-products could be used to obtain products with higher value. Pulping process generates cellulosic pulps and lignin. The lignin could be oxidized and applied in effluent treatments for heavy metal removal. Oxidized lignin presents very strong chelating properties. Lignins from sugarcane straw and bagasse were obtained by ethanol-water pulping. Oxidation of lignins was carried out using acetic acid and Co/Mn/Br catalytical system at 50, 80, and 115 °C for 5 h. Kinetics of the reaction was accomplished by measuring the UV-visible region. Activation energy was calculated for lignins from sugarcane straw and bagasse (34.2 and 23.4 kJ mol-1, respectively). The first value indicates higher cross-linked formation. Fourier-transformed infrared spectroscopy data of samples collected during oxidation are very similar. Principal component analysis applied to spectra shows only slight structure modifications in lignins after oxidation reaction.

  14. Stabilization of lignin peroxidases in white rot fungi by tryptophan.

    PubMed Central

    Collins, P J; Field, J A; Teunissen, P; Dobson, A D

    1997-01-01

    Supplementation of various cultures of white rot fungi with tryptophan was found to have a large stimulatory effect on lignin peroxidase activity levels. This enhancement was greater than that observed in the presence of the lignin peroxidase recycling agent veratryl alcohol. Using reverse transcription-PCR, we found that tryptophan does not act to induce lignin peroxidase expression at the level of gene transcription. Instead, the activity enhancement observed is likely to result from the protective effect of tryptophan against H2O2 inactivation. In experiments using a partially purified lignin peroxidase preparation, tryptophan and its derivative indole were determined to function in the same way as veratryl alcohol in converting compound II, an oxidized form of lignin peroxidase, to ferric enzyme, thereby completing the catalytic cycle. Furthermore, tryptophan was found to be a better substrate for lignin peroxidase than veratryl alcohol. Inclusion of either tryptophan or indole enhanced the oxidation of the azo dyes methyl orange and Eriochrome blue black. Stimulation of azo dye oxidations by veratryl alcohol has previously been shown to be due to its enzyme recycling function. Our data allow us to propose that tryptophan stabilizes lignin peroxidase by acting as a reductant for the enzyme. PMID:9212404

  15. Phenolic mediators enhance the manganese peroxidase catalyzed oxidation of recalcitrant lignin model compounds and synthetic lignin.

    PubMed

    Nousiainen, Paula; Kontro, Jussi; Manner, Helmiina; Hatakka, Annele; Sipilä, Jussi

    2014-11-01

    Fungal oxidative enzymes, such as peroxidases and laccases, are the key catalysts in lignin biodegradation in vivo, and consequently provide an important source for industrial ligninolytic biocatalysts. Recently, it has been shown that some syringyl-type phenolics have potential as industrial co-oxidants or mediators, in laccase-catalyzed modification of lignocellulosic material. We have now studied the effect of such mediators with ligninolytic peroxidases on oxidation of the most recalcitrant lignin model compounds. We found that they are able to enhance the manganese peroxidase (MnP) catalyzed oxidation reactions of small non-phenolic compounds, veratryl alcohol and veratrylglycerol β-guaiacyl ether (adlerol), which are not usually oxidized by manganese peroxidases alone. In these experiments we compared two peroxidases from white-rot fungi, MnP from Phlebia sp. Nf b19 and versatile peroxidase (VP) from Bjerkandera adusta under two oxidation conditions: (i) the Mn(III) initiated mediated oxidation by syringyl compounds and (ii) the system involving MnP-dependent lipid peroxidation, both with production of (hydrogen) peroxides in situ to maintain the peroxidase catalytic cycle. It was found that both peroxidases produced α-carbonyl oxidation product of veratryl alcohol in clearly higher yields in reactions mediated by phenoxy radicals than in lipid-peroxyl radical system. The oxidation of adlerol, on the other hand, was more efficient in lipid-peroxidation-system. VP was more efficient than MnP in the oxidation of veratryl alcohol and showed its lignin peroxidase type activity in the reaction conditions indicated by some cleavage of Cα-Cβ-bond of adlerol. Finally, the mediator assisted oxidation conditions were applied in the oxidation of synthetic lignin (DHP) and the structural analysis of the oxidized polymers showed clear modifications in the polymer outcome, e.g. the oxidation resulted in reduced amount of aliphatic hydroxyls indicated by (31)P NMR. PMID

  16. Preparation of different carbon materials by thermochemical conversion of Lignin

    NASA Astrophysics Data System (ADS)

    Rosas, Juana; Berenguer, Raul; Valero-Romero, Maria; Rodriguez-Mirasol, Jose; Cordero, Tomás

    2014-12-01

    Lignin valorization plays a crucial role within the modern biorefinery scheme from both the economic and environmental points of view; and the structure and composition of lignin becomes it an ideal precursor for the preparation of advanced carbon materials with high added-value. This review provides an overview of the different carbonaceous materials obtained by thermochemical conversion of lignin, such as activated carbons, carbon fibers, template carbons; high ordered carbons; giving information about the new strategies in terms of the preparation method and their possible applications.

  17. Inhibitory effect of lignin during cellulose bioconversion: the effect of lignin chemistry on non-productive enzyme adsorption.

    PubMed

    Rahikainen, Jenni L; Martin-Sampedro, Raquel; Heikkinen, Harri; Rovio, Stella; Marjamaa, Kaisa; Tamminen, Tarja; Rojas, Orlando J; Kruus, Kristiina

    2013-04-01

    The effect of lignin as an inhibitory biopolymer for the enzymatic hydrolysis of lignocellulosic biomass was studied; specially addressing the role of lignin in non-productive enzyme adsorption. Botanical origin and biomass pre-treatment give rise to differences in lignin structure and the effect of these differences on enzyme binding and inhibition were elucidated. Lignin was isolated from steam explosion (SE) pre-treated and non-treated spruce and wheat straw and used for the preparation of ultrathin films for enzyme binding studies. Binding of Trichoderma reesei Cel7A (CBHI) and the corresponding Cel7A-core, lacking the linker and the cellulose-binding domain, to the lignin films was monitored using a quartz crystal microbalance (QCM). SE pre-treatment altered the lignin structure, leading to increased enzyme adsorption. Thus, the positive effect of SE pre-treatment, opening the cell wall matrix to make polysaccharides more accessible, may be compromised by the structural changes of lignin that increase non-productive enzyme adsorption. PMID:23428824

  18. Organocatalyzed Group Transfer Polymerization.

    PubMed

    Chen, Yougen; Kakuchi, Toyoji

    2016-08-01

    In contrast to the conventional group transfer polymerization (GTP) using a catalyst of either an anionic nucleophile or a transition-metal compound, the organocatalyzed GTP has to a great extent improved the living characteristics of the polymerization from the viewpoints of synthesizing structurally well-defined acrylic polymers and constructing defect-free polymer architectures. In this article, we describe the organocatalyzed GTP from a relatively personal perspective to provide our colleagues with a perspicuous and systematic overview on its recent progress as well as a reply to the curiosity of how excellently the organocatalysts have performed in this field. The stated perspectives of this review mainly cover five aspects, in terms of the assessment of the livingness of the polymerization, limit and scope of applicable monomers, mechanistic studies, control of the polymer structure, and a new GTP methodology involving the use of tris(pentafluorophenyl)borane and hydrosilane. PMID:27427399

  19. Oxidative/antioxidative effects of different lignin preparations on DNA in hamster V79 cells.

    PubMed

    Slamenová, D; Kosíková, B; Lábaj, J; Ruzeková, L

    2000-01-01

    Endogenous oxidative damage to DNA is thought to be an important etiologic factor in the development of chronic diseases such as cancer. Many products of the vegetable kingdom have been suggested to limit oxidative damage to DNA in humans. To this group belong lignins, polyphenols present in all plants (including edible plants). The aim of this study was to examine oxidative/antioxidative effects of different lignin preparations on mammalian DNA. In addition to a water-soluble sulfur-free lignin 1 which was obtained by fractionation of hardwood hydrolysate, we investigated lignin 2 (obtained by oxidation of lignin 1), lignin 3 (prepared by the extraction of lignin 2 with a mixture ethanol-water 3:1), lignin 4 (Na-salt of lignin 3) and lignin 5 (prepared by extraction of lignin 2 with diethylether). Our results showed that only the original lignin 1 did not increase substantially the level of DNA damage. Lignins 2, 3, 4 and 5 increased both the level of frank DNA strand breaks + alkali-labile sites and the level of FPG-sensitive sites representing oxidative damage to DNA. Lignin 1 was further tested for its antioxidative activity against DNA base modifications generated by visible light+photosensitizer. Obtained results confirmed the oxygen species-scavenging activity of lignin 1. PMID:11263858

  20. Lignin in marine environment and its analysis—A review

    NASA Astrophysics Data System (ADS)

    Li, Xianguo; Zhang, Ting; Sun, Shuwen; Lan, Haiqing; Yu, Tao

    2012-12-01

    Lignin is a group of phenolic polymers which is abundant in the woody tissues of vascular plants, and is essentially absent from all other living organisms. It has therefore been accepted as a tracer for terrestrial organic carbon (TOC) in marine environment since the 1970s. Lignin polymers are not amenable to direct chemical analysis without prior isolation. This review focused on the methods of chemical decomposition, extraction, derivatization and detection of lignin in marine environment. We described and compared several chemical decomposition methods, including nitrobenzene oxidation, alkaline cupric oxide (CuO) oxidation and thermochemolysis, and detection methods such as gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS), high performance liquid chromatography (HPLC) and so on. Possible improvement of lignin analysis and the application prospects of this tracer were also discussed.

  1. Solvated liquid-lignin fractions from a Kraft black liquor.

    PubMed

    Velez, Julian; Thies, Mark C

    2013-11-01

    A softwood Kraft black liquor was acidified with carbon dioxide at 115°C and 6.2 bar over a pH range of 13.6-9.5, resulting in the precipitation of liquefied-lignin fractions as a separate phase. Seven such "liquid-lignin" fractions were produced, with each fraction being phase-separated within a narrow pH band of 0.5 units. The fractions were found to be highly hydrated phases, containing 32.3-48.2 wt.% water; as a result, their measured melting points were quite low, 90.7-110.5°C. In contrast, no melting point was detected up to 375°C for any of the lignin fractions after drying. Significant reductions in metals content were observed for the lignin fractions compared to the original black-liquor feed. PMID:24054066

  2. Membrane Technology for the Recovery of Lignin: A Review.

    PubMed

    Humpert, Daniel; Ebrahimi, Mehrdad; Czermak, Peter

    2016-01-01

    Utilization of renewable resources is becoming increasingly important, and only sustainable processes that convert such resources into useful products can achieve environmentally beneficial economic growth. Wastewater from the pulp and paper industry is an unutilized resource offering the potential to recover valuable products such as lignin, pigments, and water [1]. The recovery of lignin is particularly important because it has many applications, and membrane technology has been investigated as the basis of innovative recovery solutions. The concentration of lignin can be increased from 62 to 285 g∙L(-1) using membranes and the recovered lignin is extremely pure. Membrane technology is also scalable and adaptable to different waste liquors from the pulp and paper industry. PMID:27608047

  3. Hydrothermal fractionation of woody biomass: Lignin effect on sugars recovery.

    PubMed

    Yedro, Florencia M; Cantero, Danilo A; Pascual, Marcos; García-Serna, Juan; Cocero, M José

    2015-09-01

    Subcritical water was employed to fractionate woody biomass into carbohydrates and lignin. Nine urban trees species (hardwood and softwood) from Spain were studied. The experiments were carried out in a semi-continuous reactor at 250 °C for 64 min. The hemicellulose and cellulose recovery yields were between 30%wt. and 80%wt. while the lignin content in the solid product ranged between 32%wt. and 92%wt. It was observed that an increment of solubilized lignin disfavored the hydrolysis of hemicelluloses. It was determined that the maximum extraction of hemicellulose was achieved at 20 min of solid reaction time while the extraction of celluloses not exhibited a maximum value. The hydrolysis of hemicellulose and cellulose would be governed by the hydrolysis kinetic and the polymers accessibility. In addition, the extraction of hemicellulose was negatively affected by the lignin content in the raw material while cellulose hydrolysis was not affected by this parameter. PMID:25985415

  4. Molecular simulation as a tool for studying lignin

    SciTech Connect

    Sangha, Amandeep K; Petridis, Loukas; Smith, Jeremy C; Ziebell, Angela L; Parks, Jerry M

    2012-01-01

    Lignocellulosic biomass provides a sustainable source of sugars for biofuel and biomaterial production. However, biomass resistance to degradation imposes difficulties for economical conversion of plant carbohydrates to fermentable sugars. One of the key contributors to recalcitrance is lignin. Understanding the properties of lignin macromolecules in the cell wall matrix is useful for manipulating biomass structure to generate more easily degradable biomass. Along with experimental techniques such as 2D-NMR and mass spectrometry, computational techniques can be useful for characterizing the structural and energetic properties of the biomass assembly and its individual constituents. Here, we provide a brief introduction to lignin, review some of the recent, relevant scientific literature, and give our perspectives on the role of molecular simulation in understanding lignin structure.

  5. Lignin nanotubes as vehicles for gene delivery into human cells.

    PubMed

    Ten, Elena; Ling, Chen; Wang, Yuan; Srivastava, Arun; Dempere, Luisa Amelia; Vermerris, Wilfred

    2014-01-13

    Lignin nanotubes (LNTs) synthesized from the aromatic plant cell wall polymer lignin in a sacrificial alumina membrane template have as useful features their flexibility, ease of functionalization due to the availability of many functional groups, label-free detection by autofluorescence, and customizable optical properties. In this report we show that the physicochemical properties of LNTs can be varied over a wide range to match requirements for specific applications by using lignin with different subunit composition, a function of plant species and genotype, and by choosing the lignin isolation method (thioglycolic acid, phosphoric acid, sulfuric acid (Klason), sodium hydroxide lignin), which influences the size and reactivity of the lignin fragments. Cytotoxicity studies with human HeLa cells showed that concentrations of up to 90 mg/mL are tolerated, which is a 10-fold higher concentration than observed for single- or multiwalled carbon nanotubes (CNTs). Confocal microscopy imaging revealed that all LNT formulations enter HeLa cells without auxiliary agents and that LNTs made from NaOH-lignin penetrate the cell nucleus. We further show that DNA can adsorb to LNTs. Consequently, exposure of HeLa cells to LNTs coated with DNA encoding the green fluorescent protein (GFP) leads to transfection and expression of GFP. The highest transfection efficiency was obtained with LNTs made from NaOH-lignin due to a combination of high DNA binding capacity and DNA delivery directly into the nucleus. These combined features of LNTs make LNTs attractive as smart delivery vehicles of DNA without the cytotoxicity associated with CNTs or the immunogenicity of viral vectors. PMID:24308459

  6. Plants with modified lignin content and methods for production thereof

    SciTech Connect

    Zhao, Qiao; Chen, Fang; Dixon, Richard A.

    2014-08-05

    The invention provides methods for decreasing lignin content and for increasing the level of fermentable carbohydrates in plants by down-regulation of the NST transcription factor. Nucleic acid constructs for down-regulation of NST are described. Transgenic plants are provided that comprise reduced lignin content. Plants described herein may be used, for example, as improved biofuel feedstock and as highly digestible forage crops. Methods for processing plant tissue and for producing ethanol by utilizing such plants are also provided.

  7. Transcription factors for modification of lignin content in plants

    SciTech Connect

    Wang, Huanzhong; Chen, Fang; Dixon, Richard A.

    2015-06-02

    The invention provides methods for modifying lignin, cellulose, xylan, and hemicellulose content in plants, and for achieving ectopic lignification and, for instance, secondary cell wall synthesis in pith cells, by altered regulation of a WRKY transcription factor. Nucleic acid constructs for altered WRKY-TF expression are described. Transgenic plants are provided that comprise modified pith cell walls, and lignin, cellulose, and hemicellulose content. Plants described herein may be used, for example, as improved biofuel feedstock and as highly digestible forage crops.

  8. Evaluation of pristine lignin for hazardous-waste treatment

    SciTech Connect

    O'Neil, D.J.; Newman, C.J.; Chian, E.S.K.; Gao, H.

    1987-05-01

    A feasibility study was conducted to assess the utilization of lignin, isolated from a steam-exploded hardwood (Tulip poplar) with 95% ethanol and 0.1n NaOH, as a potential adsorbent for hazardous-waste treatment. Eight organic compounds and two heavy metals were selected to allow comparison of lignin isolates with activated carbon. It was found that the adsorption capacity of lignin for heavy metals (chromium and lead) is comparable to activated carbon, despite a huge divergence in surface area (0.1 mS/g vs. 1000 mS/g). The surface area discrepancy and the extensive aromatic substitution in lignin macromolecule impeded the achievement of an adsorption capacity of lignin for polar organic compounds which would allow it to be cost-competitive with activated carbon although results with phenol and, to a lesser degree, naphthalene indicate significant potential for achieving competitive capacities. A recommended plan for surface area and structural enhancement is presented on the basis that lignin can be developed as an effective and low-cost adsorbent for polar priority pollutants and/or as an ion-exchange resins for heavy-metal wastewater clean-up.

  9. Solubilization and Mineralization of Lignin by White Rot Fungi

    PubMed Central

    Boyle, C. David; Kropp, Bradley R.; Reid, Ian D.

    1992-01-01

    The white rot fungi Lentinula edodes, Phanerochaete chrysosporium, Pleurotus sajor-caju, Flammulina velutipes, and Schizophyllum commune were grown in liquid media containing 14C-lignin-labelled wood, and the formation of water-soluble 14C-labelled products and 14CO2, the growth of the fungi, and the activities of extracellular lignin peroxidase, manganese peroxidase, and laccase were measured. Conditions that affect the rate of lignin degradation were imposed, and both long-term (0- to 16-day) and short-term (0- to 72-h) effects on the production of the two types of product and on the activities of the enzymes were monitored. The production of 14CO2-labelled products from the aqueous ones was also investigated. The short-term studies showed that the different conditions had different effects on the production of the two products and on the activities of the enzymes. Nitrogen sources inhibited the production of both products by all species when differences in growth could be discounted. Medium pH and manganese affected lignin degradation by the different species differently. With P. chrysosporium, the results were consistent, with lignin peroxidase playing a role in lignin solubilization and manganese peroxidase being important in subsequent CO2 production. PMID:16348781

  10. Lignin structural alterations in thermochemical pretreatments with limited delignification

    SciTech Connect

    Pu, Yunqiao; Hu, Fan; Huang, Fang; Ragauskas, Arthur J.

    2015-08-02

    Lignocellulosic biomass has a complex and rigid cell wall structure that makes biomass recalcitrant to biological and chemical degradation. Among the three major structural biopolymers (i.e., cellulose, hemicellulose and lignin) in plant cell walls, lignin is considered the most recalcitrant component and generally plays a negative role in the biochemical conversion of biomass to biofuels. The conversion of biomass to biofuels through a biochemical platform usually requires a pretreatment stage to reduce the recalcitrance. Pretreatment renders compositional and structural changes of biomass with these changes ultimately govern the efficiency of the subsequent enzymatic hydrolysis. Dilute acid, hot water, steam explosion, and ammonia fiber expansion pretreatments are among the leading thermochemical pretreatments with a limited delignification that can reduce biomass recalcitrance. Practical applications of these pretreatment are rapidly developing as illustrated by recent commercial scale cellulosic ethanol plants. While these thermochemical pretreatments generally lead to only a limited delignification and no significant change of lignin content in the pretreated biomass, the lignin transformations that occur during these pretreatments and the roles they play in recalcitrance reduction is an important research aspect. This review highlights recent advances in our understanding of lignin alterations during these limited delignification thermochemical pretreatments, with emphasis on lignin chemical structures, molecular weights, and redistributions in the pretreated biomass.

  11. Lignin structural alterations in thermochemical pretreatments with limited delignification

    DOE PAGESBeta

    Pu, Yunqiao; Hu, Fan; Huang, Fang; Ragauskas, Arthur J.

    2015-08-02

    Lignocellulosic biomass has a complex and rigid cell wall structure that makes biomass recalcitrant to biological and chemical degradation. Among the three major structural biopolymers (i.e., cellulose, hemicellulose and lignin) in plant cell walls, lignin is considered the most recalcitrant component and generally plays a negative role in the biochemical conversion of biomass to biofuels. The conversion of biomass to biofuels through a biochemical platform usually requires a pretreatment stage to reduce the recalcitrance. Pretreatment renders compositional and structural changes of biomass with these changes ultimately govern the efficiency of the subsequent enzymatic hydrolysis. Dilute acid, hot water, steam explosion,more » and ammonia fiber expansion pretreatments are among the leading thermochemical pretreatments with a limited delignification that can reduce biomass recalcitrance. Practical applications of these pretreatment are rapidly developing as illustrated by recent commercial scale cellulosic ethanol plants. While these thermochemical pretreatments generally lead to only a limited delignification and no significant change of lignin content in the pretreated biomass, the lignin transformations that occur during these pretreatments and the roles they play in recalcitrance reduction is an important research aspect. This review highlights recent advances in our understanding of lignin alterations during these limited delignification thermochemical pretreatments, with emphasis on lignin chemical structures, molecular weights, and redistributions in the pretreated biomass.« less

  12. Characterization of anaerobic consortia coupled lignin depolymerization with biomethane generation.

    PubMed

    Wu, Yi-Rui; He, Jianzhong

    2013-07-01

    Two sediment-free microbial consortia (LI3 and LP3) were established to depolymerize lignin under anaerobic conditions. During depolymerizing high molecular weight lignin to low molecular weight molecules, the two cultures produced biomethane up to 151.7 and 113.0 mL g(-1) total lignin. Furthermore, LI3 and LP3 could also utilize the biomass - oil palm empty fruit bunch fiber (OPEFB) to produce 190.6 and 195.6 mL methaneg(-1) total lignin in OPEFB, and at the same time improve the bioavailability of lignocellulosic matters for further enzymatic hydrolysis. The microbial community analysis by denature gradient gel electrophoresis (DGGE) and the high-density 16S rDNA gene microarray (PhyloChip) exhibited that Methanomethylovorans sp. (LI3) and Methanoculleus sp. (LP3) were the main methanogens present, and phylum Firmicutes and Bacteroidetes were mainly involved in the lignin depolymerization. The established microbial consortia with both lignin depolymerization and biomethane production provide profound application on the environmental friendly pretreatment of lignocellulosic materials. PMID:23639408

  13. [Pretreatment of industrial lignin and catalytic conversion into phenol].

    PubMed

    Qu, Yongshui; Luo, Hao; Li, Hongqiang; Xu, Jian

    2014-05-01

    Recent concerns about the gradual depletion of conventional fossil resources and the pressure from global climate change have accentuated the need for new alternative feedstock. As one of the main components in biomass, lignin is the second most abundant natural polymer after cellulose, and has the potential to serve as a sustainable source of energy and organic carbon to replace petroleum-based chemicals. Efficient conversion of lignin into high value-added chemicals is crucial to improve the economic feasibility of biomass refinery. In the present study, several pretreatment technologies on industrial lignin were carried out to enhance phenol production. A microwave irradiation assisted biphasic reaction system was used to convert pretreated industrial lignin into phenolic compounds. Lignin conversion, reaction temperature, time and pretreatment method, were optimized. The highest phenol yield was 8.14% obtained from lignin pretreated by 1-ethyl-3-methylimidazolium acetate at 400 W for 60 min in a biophasic system catalyze by 1-aminoethyl-3-methylimidazolium tetrafluoroborate. PMID:25118400

  14. A radioimmunoassay for lignin in plant cell walls

    SciTech Connect

    Dawley, R.M.

    1989-01-01

    Lignin detection and determination in herbaceous tissue requires selective, specific assays which are not currently available. A radioimmunoassay (RIA) was developed to study lignin metabolism in these tissues. A {beta}-aryl ether lignin model compound was synthesized, linked to keyhole limpet hemocyanin using a water-soluble carbodiimide, and injected into rabbits. The highest titer of the antiserum obtained was 34 {eta}g/mL of model derivatized BSA. An in vitro system was developed to characterize the RIA. The model compound was linked to amino activated polyacrylamide beads to mimic lignin in the cell walls. {sup 125}I Radiolabelled protein A was used to detect IgG antibody binding. The RIA was shown in the in vitro system to exhibit saturable binding. The amount of antibody bound decreased when the serum was diluted. Immunoelectrophoresis and competitive binding experiments confirmed that both aromatic rings of the lignin model compound had been antigenic. Chlorogenic acid, a phenolic known to be present in plant cells, did not compete for antibody binding. The RIA was used to measure lignin in milled plant samples and barley seedlings. Antiserum binding to wheat cell walls and stressed barley segments was higher than preimmune serum binding. Antibody binding to stressed barley tissue decreased following NaClO{sub 2} delignification. The RIA was found to be less sensitive than expected, so several avenues for improving the method are discussed.

  15. Dissolved Vanillin as Tracer for Estuarine Lignin Conversion

    NASA Astrophysics Data System (ADS)

    Edelkraut, F.

    1996-12-01

    Lignin is produced only by vascular plants and therefore can be used as a tracer for terrestrial organic carbon input to the estuarine and marine environments. Lignin measurements have been done by analyses of the oxidation products such as vanillin or 4-hydroxybenzaldehyde. In the Elbe Estuary, free dissolved vanillin was analysed in order to test whether such measurements yield information on terrestrial carbon inputs into the Estuary and on the vanillin derived from lignin oxidation. In the period 1990-1992, concentrations of dissolved vanillin in the Elbe ranged from 0 to 60 μ g l -1(mean: 8 μg l -1). Higher values were found in areas of increased microbial activity such as the turbidity zone and the river mouth where the water chemistry is influenced by large tidal flats. No correlation was found between dissolved vanillin and suspended matter concentrations, although lignin is normally associated with suspended particulate matter, nor was a covariance seen between dissolved vanillin and the terrestrial carbon inputs into the Estuary. Apparently, biological conversion of lignin was faster than the transport processes, and local sources were more dominant for the vanillin concentration than riverine sources. The dissolved vanillin turnover was fast and, consequently, a significant amount of lignin may be converted within an estuary. In sediments from the Estuary, the concentrations of dissolved vanillin were similar to those found in the water phase and showed no clear vertical profile. The sediment is unlikely to be the source for vanillin.

  16. Molecular trickery in soil organic matter: hidden lignin.

    PubMed

    Hernes, Peter J; Kaiser, Klaus; Dyda, Rachael Y; Cerli, Chiara

    2013-08-20

    Binding to minerals is one mechanism crucial toward the accumulation and stabilization of organic matter (OM) in soils. Of the various biochemicals produced by plants, lignin-derived phenols are among the most surface-reactive compounds. However, it is not known to what extent mineral-bound lignin-derived phenols can be analytically assessed by alkaline CuO oxidation. We tested the potential irreversible binding of lignin from three litters (blue oak, foothill pine, annual grasses) to five minerals (ferrihydrite, goethite, kaolinite, illite, montmorillonite) using the CuO-oxidation technique, along with bulk organic carbon (OC) sorption. Up to 56% of sorbed lignin could not be extracted from the minerals with the CuO-oxidation technique. The composition of the irreversibly bound lignin component differed markedly between minerals and from that of the parent litter leachates, indicating different bonding strengths related to individual monomers and conformations. The difference in extractability of individual phenols suggests that abiotic processes, such as sorption/desorption, should be taken into account when using CuO oxidation data for assessing lignin turnover in mineral matrixes. However, given the apparent relationship between aromaticity as indicated by carbon-specific UV absorbance (SUVA) and bulk OC sorption, it is likely that irreversible sorption is a concern for any technique that addresses the broad class of aromatic/phenolic compounds in soils and sediments. PMID:23875737

  17. Variable Effect during Polymerization

    ERIC Educational Resources Information Center

    Lunsford, S. K.

    2005-01-01

    An experiment performing the polymerization of 3-methylthiophene(P-3MT) onto the conditions for the selective electrode to determine the catechol by using cyclic voltammetry was performed. The P-3MT formed under optimized conditions improved electrochemical reversibility, selectivity and reproducibility for the detection of the catechol.

  18. Polymerized and functionalized triglycerides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant oils are useful sustainable raw materials for the development of new chemical products. As part of our research emphasis in sustainability and green polymer chemistry, we have explored a new method for polymerizing epoxidized triglycerides with the use of fluorosulfonic acid. Depending on the ...

  19. Programmable Supramolecular Polymerizations.

    PubMed

    van der Zwaag, Daan; de Greef, Tom F A; Meijer, E W

    2015-07-13

    Living large: Rational design of self-assembly pathways has been demonstrated in supramolecular polymers. By controlling the concentration of an aggregation-competent monomer through intramolecular interactions, living supramolecular polymerization conditions were achieved. This universal approach can be used to obtain aggregates of well-defined length and narrow dispersity, and allows access to new supramolecular polymer architectures. PMID:26095705

  20. Effective integrative supramolecular polymerization.

    PubMed

    Zhang, Qiwei; Tian, He

    2014-09-26

    Exercise control: By taking advantage of self-sorting processes among host-guest components, a controlled supramolecular polymerization can be realized, as demonstrated recently with the preparation of a cucurbit[n]uril-based supramolecular polymer. This method may be used for the design of more ordered supramolecular polymers from complex and discrete components. PMID:25080388

  1. Protein specific polymeric immunomicrospheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Dreyer, William J. (Inventor)

    1980-01-01

    Small, round, bio-compatible microspheres capable of covalently bonding proteins and having a uniform diameter below about 3500 A are prepared by substantially instantaneously initiating polymerization of an aqueous emulsion containing no more than 35% total monomer including an acrylic monomer substituted with a covalently bondable group such as hydroxyl, amino or carboxyl and a minor amount of a cross-linking agent.

  2. Slow pyrolysis of prot, alkali and dealkaline lignins for production of chemicals.

    PubMed

    Biswas, Bijoy; Singh, Rawel; Kumar, Jitendra; Khan, Adnan Ali; Krishna, Bhavya B; Bhaskar, Thallada

    2016-08-01

    Effect of different lignins were studied during slow pyrolysis. Maximum bio-oil yield of 31.2, 34.1, and 29.5wt.% was obtained at 350, 450 and 350°C for prot lignin, alkali lignin and dealkaline lignin respectively. Maximum yield of phenolic compounds 78%, 80% and 92% from prot lignin, alkali and dealkaline lignin at 350, 450 and 350°C. The differences in the pyrolysis products indicated the source of lignins such as soft and hard wood lignins. The biochar characterisation revealed that the various ether linkages were broken during pyrolysis and lignin was converted into monomeric substituted phenols. Bio-oil showed that the relative contents of each phenolic compound changes significantly with pyrolysis temperature and also the relative contents of each compound changes with different samples. PMID:26873286

  3. Treatment of Lignin Precursors to Improve their Suitability for Carbon Fibers: A Literature Review

    SciTech Connect

    Paul, Ryan; Naskar, Amit; Gallego, Nidia; Dai, Xuliang; Hausner, Andrew

    2015-04-17

    Lignin has been investigated as a carbon fiber precursor since the 1960s. Although there have been a number of reports of successful lignin-based carbon fiber production at the lab scale, lignin-based carbon fibers are not currently commercially available. This review will highlight some of the known challenges, and also the reported methods for purifying and modifying lignin to improve it as a precursor. Lignin can come from different sources (e.g. hardwood, softwood, grasses) and extraction methods (e.g. organosolv, kraft), meaning that lignin can be found with a diversity of purity and structure. The implication of these conditions on lignin as carbon fiber precursor is not comprehensively known, especially as the lignin landscape is evolving. The work presented in this review will help guide the direction of a project between GrafTech and ORNL to develop lignin carbon fiber technology, as part of a cooperative agreement with the DOE Advanced Manufacturing Office.

  4. Role of paramagnetic polyconjugated clusters in lignin antioxidant activity (in vitro)

    NASA Astrophysics Data System (ADS)

    Dizhbite, T.; Ponomarenko, J.; Andersone, A.; Dobele, G.; Lauberts, M.; Krasilnikova, J.; Mironova-Ulmane, N.; Telysheva, G.

    2012-08-01

    Using physico-chemical methods (EPR, SEC, Py-GC/MS and UV/VIS spectroscopy) and wet chemical analysis, the characteristics of 6 hardwood lignins in terms of functionality, molecular weight and composition of lignin substructures were determined and considered together with the results of DPPH•, ABTS•+ and O2•- antioxidant assays with the aim to understand the relationships governing antioxidant properties of lignin. The strong positive linear correlation between lignin antioxidant capacity in the three assays used and the extent of conjugation of paramagnetic polyconjugated clusters in lignin macromolecules was found. The biological activity of the most active alkaline lignins was assessed by in vitro experiment with human blood.

  5. Lignin content in natural Populus variants affects sugar release

    PubMed Central

    Studer, Michael H.; DeMartini, Jaclyn D.; Davis, Mark F.; Sykes, Robert W.; Davison, Brian; Keller, Martin; Tuskan, Gerald A.; Wyman, Charles E.

    2011-01-01

    The primary obstacle to producing renewable fuels from lignocellulosic biomass is a plant's recalcitrance to releasing sugars bound in the cell wall. From a sample set of wood cores representing 1,100 individual undomesticated Populus trichocarpa trees, 47 extreme phenotypes were selected across measured lignin content and ratio of syringyl and guaiacyl units (S/G ratio). This subset was tested for total sugar release through enzymatic hydrolysis alone as well as through combined hot-water pretreatment and enzymatic hydrolysis using a high-throughput screening method. The total amount of glucan and xylan released varied widely among samples, with total sugar yields of up to 92% of the theoretical maximum. A strong negative correlation between sugar release and lignin content was only found for pretreated samples with an S/G ratio < 2.0. For higher S/G ratios, sugar release was generally higher, and the negative influence of lignin was less pronounced. When examined separately, only glucose release was correlated with lignin content and S/G ratio in this manner, whereas xylose release depended on the S/G ratio alone. For enzymatic hydrolysis without pretreatment, sugar release increased significantly with decreasing lignin content below 20%, irrespective of the S/G ratio. Furthermore, certain samples featuring average lignin content and S/G ratios exhibited exceptional sugar release. These facts suggest that factors beyond lignin and S/G ratio influence recalcitrance to sugar release and point to a critical need for deeper understanding of cell-wall structure before plants can be rationally engineered for reduced recalcitrance and efficient biofuels production. PMID:21444820

  6. Flocculation of kaolin and lignin by bovine blood and hemoglobin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polymeric flocculants are used extensively for water purification, inhibition of soil erosion, and reduction in water leakage from unlined canals. Production of highly active, renewable polymeric flocculants to replace synthetic flocculants is a priority. Using suspensions of kaolin, flocculation ...

  7. Manganese-dependent cleavage of nonphenolic lignin structures by Ceriporiopsis subvermispora in the absence of lignin peroxidase

    SciTech Connect

    Jensen, K.A. Jr.; Bao, W.; Kawai, S.

    1996-10-01

    Many ligninolytic fungi appear to lack lignin peroxidase (LiP), the enzyme generally thought to cleave nonphenolic structures in lignin. However, the fungus, Ceriporiopsis subvermispora, is able to degrade these nonphenolic structures. Experiments showed wood block cultures and defined liquid medium cultures of C. subvermispora rapidly deploymerized and mineralized a {sup 14}C-labeled, polyethylene glycol-linked, high-molecular-weight {beta}-O-4 lignin model compound (model I) that represents the major nonphenolic structure of lignin. The fungus cleaved model I between C{sub {alpha}} and C{sub {beta}} to release benzylic fragments, which were shown in isotope trapping experiments to be major products of model I metabolism. The C{sub {alpha}}-C{sub {beta}} cleavage of {beta}-O-4 lignin structures to release benzylic fragments is characteristic of LiP catalysis, but no detectable LiP activity. Three results pointed, instead, to the participation of a different enzyme, manganese peroxidase (MnP), in the degradation of nonphenolic lignin structures by C. subvermispora. (1) The degradation of model I and of exhaustively methylated (nonphenolic), {sup 14}C-labeled, synthetic lignin by the fungus in liquid cultures was almost completely inhibited when the Mn concentration of the medium was decreased from 35 {mu}M to approximately 5 {mu}M. (2) The fungus degraded model I and methylated lignin significantly faster in the presence of Tween 80, a source of unsaturated fatty acids, than it did in the presence of Tween 20, which contains only saturated fatty acids. Previous work has shown that nonphenolic lignin structures are degraded during the MnP-mediated peroxidation of unsaturated lipids. (3) In experiments with MnP, Mn(II), and unsaturated lipid in vitro, this system mimicked intact C. subvermispora cultures in that it cleaved nonphenolic {beta}-O-4 lignin model compounds between C{sub {alpha}} and C{sub {beta}} to release a benzylic fragment. 41 refs., 7 figs., 2 tabs.

  8. Frontal Polymerization in Microgravity

    NASA Technical Reports Server (NTRS)

    Pojman, John A.

    1999-01-01

    Frontal polymerization systems, with their inherent large thermal and compositional gradients, are greatly affected by buoyancy-driven convection. Sounding rocket experiments allowed the preparation of benchmark materials and demonstrated that methods to suppress the Rayleigh-Taylor instability in ground-based research did not significantly affect the molecular weight of the polymer. Experiments under weightlessness show clearly that bubbles produced during the reaction interact very differently than under 1 g.

  9. Polymeric Bicontinuous Microemulsions

    NASA Astrophysics Data System (ADS)

    Bates, Frank S.; Maurer, Wayne W.; Lipic, Paul M.; Hillmyer, Marc A.; Almdal, Kristoffer; Mortensen, Kell; Fredrickson, Glenn H.; Lodge, Timothy P.

    1997-08-01

    High molecular weight block copolymers can be viewed as macromolecular surfactants when blended with thermodynamically incompatible homopolymers. This Letter describes the formation of polymeric bicontinuous microemulsions in mixtures containing a model diblock copolymer and two homopolymers. Although we attribute development of this equilibrium morphology to the effects of fluctuations, mean-field theory provides a quantitative strategy for preparing the bicontinuous state at blend compositions near an isotropic Lifshitz point.

  10. Surface polymerization agents

    SciTech Connect

    Taylor, C.; Wilkerson, C.

    1996-12-01

    This is the final report of a 1-year, Laboratory-Directed R&D project at LANL. A joint technical demonstration was proposed between US Army Missile Command (Redstone Arsenal) and LANL. Objective was to demonstrate that an unmanned vehicle or missile could be used as a platform to deliver a surface polymerization agent in such a manner as to obstruct the filters of an air-breathing mechanism, resulting in operational failure.

  11. On the surface interactions of proteins with lignin.

    PubMed

    Salas, Carlos; Rojas, Orlando J; Lucia, Lucian A; Hubbe, Martin A; Genzer, Jan

    2013-01-01

    Lignins are used often in formulations involving proteins but little is known about the surface interactions between these important biomacromolecules. In this work, we investigate the interactions at the solid-liquid interface of lignin with the two main proteins in soy, glycinin (11S) and β-conglycinin (7S). The extent of adsorption of 11S and 7S onto lignin films and the degree of hydration of the interfacial layers is quantified via Quartz crystal microgravimetry (QCM) and surface plasmon resonance (SPR). Solution ionic strength and protein denaturation (2-mercaptoethanol and urea) critically affect the adsorption process as protein molecules undergo conformational changes and their hydrophobic or hydrophilic amino acid residues interact with the surrounding medium. In general, the adsorption of the undenatured proteins onto lignin is more extensive compared to that of the denatured biomolecules and a large amount of water is coupled to the adsorbed molecules. The reduction in water contact angle after protein adsorption (by ~40° and 35° for undenatured 11S and 7S, respectively) is explained by strong nonspecific interactions between soy proteins and lignin. PMID:23234476

  12. Coupling and Reactions of 5-Hydroxyconiferyl Alcohol in Lignin Formation.

    PubMed

    Elder, Thomas; Berstis, Laura; Beckham, Gregg T; Crowley, Michael F

    2016-06-15

    The catechol alcohols, caffeyl and 5-hydroxyconiferyl alcohol, may be incorporated into lignin either naturally or through genetic manipulation. Due to the presence of o-OH groups, these compounds form benzodioxanes, a departure from the interunit connections found in lignins derived from the cinnamyl alcohols. In nature, lignins composed of caffeyl and 5-hydroxyconiferyl alcohol are linear homopolymers and, as such, may have properties that make them amenable for use in value-added products, such as lignin-based carbon fibers. In the current work, results from density functional theory calculations for the reactions of 5-hydroxyconiferyl alcohol, taking stereochemistry into account, are reported. Dehydrogenation and quinone methide formation are found to be thermodynamically favored for 5-hydroxyconiferyl alcohol, over coniferyl alcohol. The comparative energetics of the rearomatization reactions suggest that the formation of the benzodioxane linkage is under kinetic control. Ring-opening reactions of the benzodioxane groups show that the bond dissociation enthalpy of the α-O cleavage reaction is lower than that of the β-O reaction. The catechol lignins represent a novel form of the polymer that may offer new opportunities for bioproducts and genetic targets. PMID:27236926

  13. Cinnamic acid increases lignin production and inhibits soybean root growth.

    PubMed

    Salvador, Victor Hugo; Lima, Rogério Barbosa; dos Santos, Wanderley Dantas; Soares, Anderson Ricardo; Böhm, Paulo Alfredo Feitoza; Marchiosi, Rogério; Ferrarese, Maria de Lourdes Lucio; Ferrarese-Filho, Osvaldo

    2013-01-01

    Cinnamic acid is a known allelochemical that affects seed germination and plant root growth and therefore influences several metabolic processes. In the present work, we evaluated its effects on growth, indole-3-acetic acid (IAA) oxidase and cinnamate 4-hydroxylase (C4H) activities and lignin monomer composition in soybean (Glycine max) roots. The results revealed that exogenously applied cinnamic acid inhibited root growth and increased IAA oxidase and C4H activities. The allelochemical increased the total lignin content, thus altering the sum and ratios of the p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) lignin monomers. When applied alone or with cinnamic acid, piperonylic acid (PIP, a quasi-irreversible inhibitor of C4H) reduced C4H activity, lignin and the H, G, S monomer content compared to the cinnamic acid treatment. Taken together, these results indicate that exogenously applied cinnamic acid can be channeled into the phenylpropanoid pathway via the C4H reaction, resulting in an increase in H lignin. In conjunction with enhanced IAA oxidase activity, these metabolic responses lead to the stiffening of the cell wall and are followed by a reduction in soybean root growth. PMID:23922685

  14. Degradation of carbohydrates and lignins in buried woods

    USGS Publications Warehouse

    Hedges, J.I.; Cowie, G.L.; Ertel, J.R.; James, Barbour R.; Hatcher, P.G.

    1985-01-01

    Spruce, alder, and oak woods deposited in coastal sediments were characterized versus their modern counterparts by quantification of individual neutral sugars and lignin-derived phenols as well as by scanning electron microscopy, 13C NMR, and elemental analysis. The buried spruce wood from a 2500 yr old deposit was unaltered whereas an alder wood from the same horizon and an oak wood from an open ocean sediment were profoundly degraded. Individual sugar and lignin phenol analyses indicate that at least 90 and 98 wt% of the initial total polysaccharides in the buried alder and oak woods, respectively, have been degraded along with 15-25 wt% of the lignin. At least 75% of the degraded biopolymer has been physically lost from these samples. This evidence is supported by the SEM, 13C NMR and elemental analyses, all of which indicate selective loss of the carbohydrate moiety. The following order of stability was observed for the major biochemical constituents of both buried hardwoods: vanillyl and p-hydroxyl lignin structural units > syringyl lignin structural units > pectin > ??-cellulose > hemicellulose. This sequence can be explained by selective preservation of the compound middle lamella regions of the wood cell walls. The magnitude and selectivity of the indicated diagenetic reactions are sufficient to cause major changes in the chemical compositions of wood-rich sedimentary organic mixtures and to provide a potentially large in situ nutrient source. ?? 1985.

  15. Small Glycosylated Lignin Oligomers Are Stored in Arabidopsis Leaf Vacuoles

    PubMed Central

    Dima, Oana; Morreel, Kris; Vanholme, Bartel; Kim, Hoon; Ralph, John; Boerjan, Wout

    2015-01-01

    Lignin is an aromatic polymer derived from the combinatorial coupling of monolignol radicals in the cell wall. Recently, various glycosylated lignin oligomers have been revealed in Arabidopsis thaliana. Given that monolignol oxidation and monolignol radical coupling are known to occur in the apoplast, and glycosylation in the cytoplasm, it raises questions about the subcellular localization of glycosylated lignin oligomer biosynthesis and their storage. By metabolite profiling of Arabidopsis leaf vacuoles, we show that the leaf vacuole stores a large number of these small glycosylated lignin oligomers. Their structural variety and the incorporation of alternative monomers, as observed in Arabidopsis mutants with altered monolignol biosynthesis, indicate that they are all formed by combinatorial radical coupling. In contrast to the common believe that combinatorial coupling is restricted to the apoplast, we hypothesized that the aglycones of these compounds are made within the cell. To investigate this, leaf protoplast cultures were cofed with 13C6-labeled coniferyl alcohol and a 13C4-labeled dimer of coniferyl alcohol. Metabolite profiling of the cofed protoplasts provided strong support for the occurrence of intracellular monolignol coupling. We therefore propose a metabolic pathway involving intracellular combinatorial coupling of monolignol radicals, followed by oligomer glycosylation and vacuolar import, which shares characteristics with both lignin and lignan biosynthesis. PMID:25700483

  16. Investigation on the structural effect of lignin during the hydrogenolysis process.

    PubMed

    Shu, Riyang; Long, Jinxing; Xu, Ying; Ma, Longlong; Zhang, Qi; Wang, Tiejun; Wang, Chenguang; Yuan, Zhengqiu; Wu, Qingyun

    2016-01-01

    Structure has a significant effect on the lignin degradation, so the investigation of structural effect on the lignin depolymerization is important and imperative. In this study, hydrogenolysis of three typical lignins with different structures, dealkaline lignin, sodium lignosulfonate and organosolv lignin, was intensively compared over the synergistic catalyst of CrCl3 and Pd/C. The effects of reaction temperature, time, hydrogen pressure and catalyst dosage on the catalytic performance of lignin species were investigated. The structure evolution of lignins during the hydrogenolysis process was also compared. The results showed that organosolv lignin was more sensitive for hydrogenolysis than others due to its high unsaturation degree and low molecular weight. Further analysis indicated that the hydrogenolysis, hydrodeoxygenation and repolymerization reactions took place and competed intensely. Wherein, the depolymerization products with unsaturated carbonyl groups were prone to repolymerize. And the methylation was helpful to stabilize the depolymerization products and suppress the further repolymerization. PMID:26476159

  17. Modification of Lignins by Growing Cells of the Sulfate-Reducing Anaerobe Desulfovibrio desulfuricans†

    PubMed Central

    Ziomek, E.; Williams, R. E.

    1989-01-01

    The anaerobic sulfate-reducing bacterium Desulfovibrio desulfuricans was grown on medium supplemented with either Kraft lignin or lignosulfonate. Only lignosulfonate contributed to the growth of D. desulfuricans cells, by replacing sulfate, a natural electron acceptor for this microorganism. Kraft lignin added to the culture medium could not substitute for lactate or sulfate, both necessary culture medium components. However, it was found to enhance the viability of D. desulfuricans cells. When changes occurring in lignin during growth of Desulfovibrio cultures were monitored, it was found that both lignin preparations could be partially depolymerized. Spectrophotometric and elemental analysis of biologically treated lignins suggested that both the polyphenolic backbone and lignin functional groups were affected by D. desulfuricans. After treatment, a twofold increase in the sulfur content of Kraft lignin and a minor decrease (14%) in the sulfur content of lignosulfonate were observed. After biological treatment, Kraft lignin and lignosulfonate both bound larger quantities of heavy metals. PMID:16348007

  18. Advanced process for precipitation of lignin from ethanol organosolv spent liquors.

    PubMed

    Schulze, Peter; Seidel-Morgenstern, Andreas; Lorenz, Heike; Leschinsky, Moritz; Unkelbach, Gerd

    2016-01-01

    An advanced process for lignin precipitation from organosolv spent liquors based on ethanol evaporation was developed. The process avoids lignin incrustations in the reactor, enhances filterability of the precipitated lignin particles and significantly reduces the liquor mass in downstream processes. Initially, lignin solubility and softening properties were understood, quantified and exploited to design an improved precipitation process. Lignin incrustations were avoided by targeted precipitation of solid lignin at specific conditions (e.g. 100 mbar evaporation pressure, 43°C and 10%wt. of ethanol in lignin dispersion) in fed-batch operation at lab and pilot scale. As result of evaporation the mass of spent liquor was reduced by about 50%wt., thus avoiding large process streams. By controlled droplet coalescence the mean lignin particle size increased from below 10 μm to sizes larger than 10 μm improving the significantly filterability. PMID:26459197

  19. Improved lignin pyrolysis for phenolics production in a bubbling bed reactor--Effect of bed materials.

    PubMed

    Li, Dongbing; Briens, Cedric; Berruti, Franco

    2015-01-01

    Lignin pyrolysis was studied in a bubbling fluidized bed reactor equipped with a fractional condensation train, using nitrogen as the fluidization gas. The effect of different bed materials (silica sand, lignin char, activated lignin char, birch bark char, and foamed glass beads) on bio-oil yield and quality was investigated for a pyrolysis temperature of 550 °C. Results how that a bed of activated lignin char is preferable to the commonly used silica sand: pyrolysis of Kraft lignin with a bed of activated lignin char not only provides a pure char product, but also a higher dry bio-oil yield (with a relative increase of 43%), lower pyrolytic water production, and better bio-oil quality. The bio-oil obtained from Kraft lignin pyrolysis with a bed of activated lignin char has a lower average molecular weight, less tar, more phenolics, and less acidity than when sand is used as bed material. PMID:25863324

  20. Tailoring lignin biosynthesis for efficient and sustainable biofuel production.

    PubMed

    Liu, Chang-Jun; Cai, Yuanheng; Zhang, Xuebin; Gou, Mingyue; Yang, Huijun

    2014-12-01

    Increased global interest in a bio-based economy has reinvigorated the research on the cell wall structure and composition in plants. In particular, the study of plant lignification has become a central focus, with respect to its intractability and negative impact on the utilization of the cell wall biomass for producing biofuels and bio-based chemicals. Striking progress has been achieved in the last few years both on our fundamental understanding of lignin biosynthesis, deposition and assembly, and on the interplay of lignin synthesis with the plant growth and development. With the knowledge gleaned from basic studies, researchers are now able to invent and develop elegant biotechnological strategies to sophisticatedly manipulate the quantity and structure of lignin and thus to create economically viable bioenergy feedstocks. These concerted efforts open an avenue for the commercial production of cost-competitive biofuel to meet our energy needs. PMID:25209835

  1. From waste to functional additive: toughening epoxy resin with lignin.

    PubMed

    Liu, Wanshuang; Zhou, Rui; Goh, Hwee Li Sally; Huang, Shu; Lu, Xuehong

    2014-04-23

    A novel approach to toughen epoxy resin with lignin, a common waste material from the pulp and paper industry, is presented in this article. First, carboxylic acid-functionalized alkali lignin (AL-COOH) was prepared and subsequently incorporated into anhydride-cured epoxy networks via a one-pot method. The results of mechanical tests show that covalent incorporation of rigid AL-COOH into epoxy networks can significantly toughen the epoxy matrix without deteriorating its tensile strength and modulus. The addition of 1.0 wt % AL-COOH gives increases of 68 and 164% in the critical stress intensity factor (K(IC)) and critical strain energy release rate (G(IC)), respectively, relative to that of neat epoxy. This article opens up the possibility of utilizing low-cost and renewable lignin feedstocks as effective toughening agents for thermoset polymers. PMID:24660855

  2. In situ micro-spectroscopic investigation of lignin in poplar cell walls pretreated by maleic acid

    DOE PAGESBeta

    Zeng, Yining; Zhao, Shuai; Wei, Hui; Tucker, Melvin P.; Himmel, Michael E.; Mosier, Nathan S.; Meilan, Richard; Ding, Shi -You

    2015-08-27

    In higher plant cells, lignin provides necessary physical support for plant growth and resistance to attack by microorganisms. For the same reason, lignin is considered to be a major impediment to the process of deconstructing biomass to simple sugars by hydrolytic enzymes. Furthermore, the in situ variation of lignin in plant cell walls is important for better understanding of the roles lignin play in biomass recalcitrance.

  3. Efficient cobalt-catalyzed oxidative conversion of lignin models to benzoquinones.

    PubMed

    Biannic, Berenger; Bozell, Joseph J

    2013-06-01

    Phenolic lignin model monomers and dimers representing the primary substructural units of lignin were successfully oxidized to benzoquinones in high yield with molecular oxygen using new Co-Schiff base catalysts bearing a bulky heterocyclic nitrogen base as a substituent. This is the first example of a catalytic system able to convert both S and G lignin model phenols in high yield, a process necessary for effective use of lignin as a chemical feedstock. PMID:23679189

  4. Demonstration of Lignin-to-Peroxidase Direct Electron Transfer

    PubMed Central

    Sáez-Jiménez, Verónica; Baratto, Maria Camilla; Pogni, Rebecca; Rencoret, Jorge; Gutiérrez, Ana; Santos, José Ignacio; Martínez, Angel T.; Ruiz-Dueñas, Francisco Javier

    2015-01-01

    Versatile peroxidase (VP) is a high redox-potential peroxidase of biotechnological interest that is able to oxidize phenolic and non-phenolic aromatics, Mn2+, and different dyes. The ability of VP from Pleurotus eryngii to oxidize water-soluble lignins (softwood and hardwood lignosulfonates) is demonstrated here by a combination of directed mutagenesis and spectroscopic techniques, among others. In addition, direct electron transfer between the peroxidase and the lignin macromolecule was kinetically characterized using stopped-flow spectrophotometry. VP variants were used to show that this reaction strongly depends on the presence of a solvent-exposed tryptophan residue (Trp-164). Moreover, the tryptophanyl radical detected by EPR spectroscopy of H2O2-activated VP (being absent from the W164S variant) was identified as catalytically active because it was reduced during lignosulfonate oxidation, resulting in the appearance of a lignin radical. The decrease of lignin fluorescence (excitation at 355 nm/emission at 400 nm) during VP treatment under steady-state conditions was accompanied by a decrease of the lignin (aromatic nuclei and side chains) signals in one-dimensional and two-dimensional NMR spectra, confirming the ligninolytic capabilities of the enzyme. Simultaneously, size-exclusion chromatography showed an increase of the molecular mass of the modified residual lignin, especially for the (low molecular mass) hardwood lignosulfonate, revealing that the oxidation products tend to recondense during the VP treatment. Finally, mutagenesis of selected residues neighboring Trp-164 resulted in improved apparent second-order rate constants for lignosulfonate reactions, revealing that changes in its protein environment (modifying the net negative charge and/or substrate accessibility/binding) can modulate the reactivity of the catalytic tryptophan. PMID:26240145

  5. Characterization of lignin and Mn peroxidases from Phanerochaete chrysosporium

    SciTech Connect

    Not Available

    1991-01-01

    Long-term objectives are to elucidate the role and mechanism of the various isozymes in lignin biodegradation. Work is described on electrochemical studies on lignin and Mn peroxidases. This study was performed to investigate the structural aspects which confer the lignin and Mn peroxidases with their high reactivity. The experimentally determined redox potential of the Fe{sup 3+}/Fe{sup 2+} couple for the lignin peroxidase isozymes H1, H2, H8 and H10 are very similar, near-130 mV. The redox potential for the Mn peroxidase isozymes H3 and H4 are similar to each other ({minus}88 mV and {minus}95 mV, respectively) and are more positive than the lignin peroxidases. The higher redox potential for the Fe{sup 3+}/Fe{sup 2+} couple is consistent with the heme active site of these fungal peroxidases being more electron deficient. To investigate the accessibility of the heme active site to the substrate which is oxidized (veratryl alcohol and Mn (II)), we investigated whether these substrates had any affect on the redox potential of the heme. The E{sub m7} value for lignin and Mn peroxidases are not affected by their respective substrates, veratryl alcohol and Mn (II). These results suggest that substrates do not directly interact with the ferric heme-iron as axial ligands. This is consistent with the present model for peroxidase catalysis. Suicide inhibitor (1) and nmr studies (2) indicate that the heme-iron of horseradish peroxidase (HRP) is not fully accessible to bulky substrates occur at the periphery of the heme.

  6. Evidence for Complex Molecular Architectures for Solvent-Extracted Lignins

    SciTech Connect

    Rials, Timothy G; Urban, Volker S; Langan, Paul

    2012-01-01

    Lignin, an abundant, naturally occurring biopolymer, is often considered 'waste' and used as a simple fuel source in the paper-making process. However, lignin has emerged as a promising renewable resource for engineering materials, such as carbon fibers. Unfortunately, the molecular architecture of lignin (in vivo and extracted) is still elusive, with numerous conflicting reports in the literature, and knowledge of this structure is extremely important, not only for materials technologies, but also for production of biofuels such as cellulosic ethanol due to biomass recalcitrance. As such, the molecular structures of solvent-extracted (sulfur-free) lignins, which have been modified using various acyl chlorides, have been probed using small-angle X-ray (SAXS) and neutron (SANS) scattering in tetrahydrofuran (THF) solution along with hydrodynamic characterization using dilute solution viscometry and gel permeation chromatography (GPC) in THF. Mass spectrometry shows an absolute molecular weight {approx}18-30 kDa ({approx}80-140 monomers), while GPC shows a relative molecular weight {approx}3 kDa. A linear styrene oligomer (2.5 kDa) was also analyzed in THF using SANS. Results clearly show that lignin molecular architectures are somewhat rigid and complex, ranging from nanogels to hyperbranched macromolecules, not linear oligomers or physical assemblies of oligomers, which is consistent with previously proposed delignification (extraction) mechanisms. Future characterization using the methods discussed here can be used to guide extraction processes as well as genetic engineering technologies to convert lignin into value added materials with the potential for high positive impact on global sustainability.

  7. Comparative geochemistries of lignins and carbohydrates in an anoxic fjord

    SciTech Connect

    Hamilton, S.E.; Hedges, J.I.

    1988-01-01

    A reducing, varved sediment core and monthly (May-September) plankton and sediment trap samples from Saanich Inlet, B.C., Canada, were analyzed for their elemental, lignin and neutral sugar compositions. Total yields of lignin-derived phenols from both the sediment trap and core samples indicated less than 15% and 30%, respectively, of chemically recognizable vascular plant remains, derived predominantly from gymnosperm wood and nonwoody angiosperm tissues. The elevated vanillyl and syringyl acid/aldehyde ratios of this material compared to fresh plant material indicated that it suffered mild aerobic decomposition prior to introduction to the Inlet. Organic carbon, total nitrogen, and total neutral sugars and lignin phenols all exhibited decreasing concentrations with depth in a region of uniform varving (upper 15 cm) in the sediment core. Neutral sugars were consistently the most reactive chemical class, accounting for roughly 15% of the total organic carbon turnover. Although lignin appeared to be degraded within the sediment core, this degradation was nonselective for different lignin types and did not lead to increased acid/aldehyde ratios as occur during aerobic lignin decomposition. Comparisons of the yields of individual neutral sugars from the sediment and sediment trap samples to those expected from the vascular plant component alone indicated that the vascular plant debris in the upper portion of the sediment core had lost a portion of its initial glucose, lyxose, and mannose. In contrast, rhamnose and fucose were produced by all samples in large excess of total yields expected for chemically intact vascular plant and plankton components and must have additional sources.

  8. Conversion of lignin into a precursor for the production of graphitic carbon materials

    SciTech Connect

    Nelson, C.M.; Serio, M.A.; Kroo, E.

    1995-11-01

    Lignin is the most abundant renewable aromatic material. There are roughly 25 x 10{sup 6} tons of lignin produced each year as a byproduct of pulp and papermaking which has a fuel value of between $0.00 and $0.04 per pound. Carbon materials are among the highest value products can be produced from lignin. Consequently, the development of processes which can utilize lignins for carbon fibers or the production of other high value carbon materials has the potential for a high payoff. It would also result in the utilization of lignin as a raw material for high technology, internationally competitive industries. The ability to form graphitic carbon materials from pitch depends on the development of a liquid crystal system called mesophase. A major problem with using lignin as a precursor for the production of mesophase pitch is the high oxygen functional group concentration of lignin which makes it reactive toward crosslinking. Hydrothermal treatment of lignin allows for selective removal of the reactive oxygen functional groups from lignin which normally prevent extensive mesophase formation. Hydrothermal pretreatment of lignin substantially increases the mesophase content of lignin-derived pitch. This development will make lignin a suitable precursor for a range of carbon materials applications.

  9. Genetics and chemistry of lignin degradation by Streptomyces. Final technical report

    SciTech Connect

    Crawford, D.L.

    1992-12-31

    Our research goal was to define the involvement of lignin peroxidases and other extracellular enzymes in lignin degradation by Streptomyces. We examined the biochemistry and genetics of lignin degrading enzyme production by several strains of Streptomyces. The lignin peroxidase ALiP-P3 of S. viridosporus was characterized kinetically and its activity optimized for oxidation of 2,4-dichlorophenol and vanillyl-acetone. Sensitive spectrophotometric assays were developed for monitoring oxidation of these substrates. ALiP-P3 reaction chemistry was examined using both spectrophotometric assays and gas chromatography/mass spectroscopy. Results showed that the enzyme oxidizes phenolic lignin substructure models in strong preference to nonphenolic ones. The peroxidase was also shown to depolymerize native lignin. We also cloned the ALip-P3 gene S. lividans in plasmid vector pIJ702. The cloned gene was partially sequenced, We also immunologically characterized the lignin peroxidase of S. viridosporus T7A and showed it to be structurally related to peroxidases produced by other lignin-solubilizing Streptomyces, but not the the H8 lignin peroxidase of P. chrysosporium. Studies with peroxidase deficient mutants of strain T7A showed that lignin peroxidases of S. viridosporus are directly involved in the solubilization of lignin. Additional research showed that other enzymes are also probably involved in lignin solubilization, possibly including extracellular esterases.

  10. Characterization and analysis of the molecular weight of lignin for biorefining studies

    SciTech Connect

    Tolbert, Allison; Akinosho, Hannah; Khunsupat, Taya Ratayakorn; Naskar, Amit K; Ragauskas, Arthur

    2014-01-01

    The molecular weight of lignin is a fundamental property that infl uences the recalcitrance of biomass and the valorization of lignin. The determination of the molecular weight of lignin in native biomass is dependent on the bioresources used and the isolation and purifi cation procedures employed. The three most commonly employed isolation methods are milled wood lignin (MWL), cellulolytic enzyme lignin (CEL), and enzymatic mild acidolysis lignin (EMAL). Common characterization techniques for determining the molecular weight of lignin will be addressed, with an emphasis on gel permeation chromatography (GPC). This review also examines the mechanisms behind several biological, physical, and chemical pre-treatments and their impact on the molecular weight of lignin. The number average molecular weight (Mn), weight average molecular weight (Mw) and polydispersity index (D) all vary in magnitude depending on the biomass source, pre-treatment conditions, and isolation method. Additionally, there is a growing body of literature that supports changes in the molecular weight of lignin in response to genetic modifi cations in the lignin biosynthetic pathways. This review summarizes different procedures for obtaining the molecular weight of lignin that have been used in recent years and highlight future opportunities for applications of lignin.

  11. Visualizing Lignin Coalescence and Migration Through Maize Cell Walls Following Thermochemical Pretreatment

    SciTech Connect

    Donohoe, B. S.; Decker, S. R.; Tucker, M. P.; Himmel, M. E.; Vinzant, T. B.

    2008-12-01

    Plant cell walls are composed primarily of cellulose, hemicelluloses, lignins, and pectins. Of these components, lignins exhibit unique chemistry and physiological functions. Although lignins can be used as a product feedstock or as a fuel, lignins are also generally seen as a barrier to efficient enzymatic breakdown of biomass to sugars. Indeed, many pretreatment strategies focus on removing a significant fraction of lignin from biomass to better enable saccharification. In order to better understand the fate of biomass lignins that remain with the solids following dilute acid pretreatment, we undertook a structural investigation to track lignins on and in biomass cell walls. SEM and TEM imaging revealed a range of droplet morphologies that appear on and within cell walls of pretreated biomass; as well as the specific ultrastructural regions that accumulate the droplets. These droplets were shown to contain lignin by FTIR, NMR, antibody labeling, and cytochemical staining. We provide evidence supporting the idea that thermochemical pretreatments reaching temperatures above the range for lignin phase transition cause lignins to coalesce into larger molten bodies that migrate within and out of the cell wall, and can redeposit on the surface of plant cell walls. This decompartmentalization and relocalization of lignins is likely to be at least as important as lignin removal in the quest to improve the digestibility of biomass for sugars and fuels production.

  12. Isolation and characterization of lignin from the oak wood bioethanol production residue for adhesives.

    PubMed

    Lee, Soo Jung; Kim, Hyun Joo; Cho, Eun Jin; Song, Younho; Bae, Hyeun-Jong

    2015-01-01

    Lignin was isolated from the residue of bioethanol production with oak wood via alkaline and catalyzed organosolv treatments at ambient temperature to improve the purity of lignin for the materials application. The isolated lignins were analyzed for their chemical composition by nitrobenzene oxidation method and their functionality was characterized via wet chemistry method, element analysis, (1)H NMR, GPC and FTIR-ATR. The isolated lignin by acid catalyzed organosolv treatment (Acid-OSL) contained a higher lignin content, aromatic proton, phenolic hydroxyl group and a lower nitrogen content that is more reactive towards chemical modification. The lignin-based adhesives were prepared and the bond strength was measured to evaluate the enhanced reactivity of lignin by the isolation. Two steps of phenolation and methylolation were applied for the modification of the isolated lignins and their tensile strengths were evaluated for the use as an adhesive. The acid catalyzed organosolv lignin-based adhesives had comparable bond strength to phenol-formaldehyde adhesives. The analysis of lignin-based adhesives by FTIR-ATR and TGA showed structural similarity to phenol adhesive. The results demonstrate that the reactivity of lignin was enhanced by isolation from hardwood bioethanol production residues at ambient temperature and it could be used in a value-added application to produce lignin-based adhesives. PMID:25453284

  13. Antimicrobial and antioxidant activities of lignin from residue of corn stover to ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To improve the economic viability of the biofuel production from biomass resource, a value-added lignin byproduct from this process is increasingly interested. Antioxidant and antimicrobial activities of lignin extracted from residue of corn stover to ethanol production were investigated. The lignin...

  14. Structural insights into the affinity of Cel7A carbohydrate-binding module for lignin.

    PubMed

    Strobel, Kathryn L; Pfeiffer, Katherine A; Blanch, Harvey W; Clark, Douglas S

    2015-09-11

    The high cost of hydrolytic enzymes impedes the commercial production of lignocellulosic biofuels. High enzyme loadings are required in part due to their non-productive adsorption to lignin, a major component of biomass. Despite numerous studies documenting cellulase adsorption to lignin, few attempts have been made to engineer enzymes to reduce lignin binding. In this work, we used alanine-scanning mutagenesis to elucidate the structural basis for the lignin affinity of Trichoderma reesei Cel7A carbohydrate binding module (CBM). T. reesei Cel7A CBM mutants were produced with a Talaromyces emersonii Cel7A catalytic domain and screened for their binding to cellulose and lignin. Mutation of aromatic and polar residues on the planar face of the CBM greatly decreased binding to both cellulose and lignin, supporting the hypothesis that the cellulose-binding face is also responsible for lignin affinity. Cellulose and lignin affinity of the 31 mutants were highly correlated, although several mutants displayed selective reductions in lignin or cellulose affinity. Four mutants with increased cellulose selectivity (Q2A, H4A, V18A, and P30A) did not exhibit improved hydrolysis of cellulose in the presence of lignin. Further reduction in lignin affinity while maintaining a high level of cellulose affinity is thus necessary to generate an enzyme with improved hydrolysis capability. This work provides insights into the structural underpinnings of lignin affinity, identifies residues amenable to mutation without compromising cellulose affinity, and informs engineering strategies for family one CBMs. PMID:26209638

  15. [Ecological and hygienic evaluation of the lignin by-products utilization].

    PubMed

    Semenova, V V; Vorob'eva, L V; Chernova, G I

    2002-01-01

    Main trends in utilization of lignin wastes formed in complex wood processing are discussed. Toxicological and hygienic characteristics of lignins and products of their biotransformation and chlorination are presented. Ecology and hygiene of fertilizers, preserving agents, and construction materials based on lignins are evaluated. PMID:11899881

  16. Insect resistance of a full sib family of tetraploid switchgrass with varying lignin levels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lignin is a plant resistance mechanism against insects. Reduction of lignin in biomass grasses in order to increase the efficiency of fermentation may result in increased susceptibility to insect feeding, interfering with sustainable production. Field grown leaves of high- and low-lignin parent and ...

  17. Structural Insights into the Affinity of Cel7A Carbohydrate-binding Module for Lignin*

    PubMed Central

    Strobel, Kathryn L.; Pfeiffer, Katherine A.; Blanch, Harvey W.; Clark, Douglas S.

    2015-01-01

    The high cost of hydrolytic enzymes impedes the commercial production of lignocellulosic biofuels. High enzyme loadings are required in part due to their non-productive adsorption to lignin, a major component of biomass. Despite numerous studies documenting cellulase adsorption to lignin, few attempts have been made to engineer enzymes to reduce lignin binding. In this work, we used alanine-scanning mutagenesis to elucidate the structural basis for the lignin affinity of Trichoderma reesei Cel7A carbohydrate binding module (CBM). T. reesei Cel7A CBM mutants were produced with a Talaromyces emersonii Cel7A catalytic domain and screened for their binding to cellulose and lignin. Mutation of aromatic and polar residues on the planar face of the CBM greatly decreased binding to both cellulose and lignin, supporting the hypothesis that the cellulose-binding face is also responsible for lignin affinity. Cellulose and lignin affinity of the 31 mutants were highly correlated, although several mutants displayed selective reductions in lignin or cellulose affinity. Four mutants with increased cellulose selectivity (Q2A, H4A, V18A, and P30A) did not exhibit improved hydrolysis of cellulose in the presence of lignin. Further reduction in lignin affinity while maintaining a high level of cellulose affinity is thus necessary to generate an enzyme with improved hydrolysis capability. This work provides insights into the structural underpinnings of lignin affinity, identifies residues amenable to mutation without compromising cellulose affinity, and informs engineering strategies for family one CBMs. PMID:26209638

  18. Surface modification of coir fibre involving oxidation of lignins followed by reaction with furfuryl alcohol: Characterization and stability

    NASA Astrophysics Data System (ADS)

    Saw, Sudhir Kumar; Sarkhel, Gautam; Choudhury, Arup

    2011-02-01

    In this study, the chemical treatment of the coir fibres was executed through oxidation with aqueous ClO2 followed by grafting with furfuryl alcohol (FA), leading to create a coating around the fibres more compatible with the polymeric matrices. The ClO2 was used to oxidize mainly phenolic syringyl and guaiacyl units of the lignin polymer to create quinones, which were characterized by UV-vis spectroscopy and Fourier transform infrared spectroscopy. In addition, the surface features of modified fibres were studied using scanning electron microscopy. The extent of FA-grafting was found higher (weight gain 17.7%) for oxidized fibre compared to those for non-oxidized fibre (weight gain 2.2%). The surface modification with FA-grafting reduced the hydrophilicity of the coir fibre, as confirm by the dynamic contact angle and water absorption measurements. The thermal and mechanical properties of untreated, oxidized and FA-grafted coir fibres were evaluated and compared.

  19. Acrylic esters in radiation polymerization

    SciTech Connect

    Fomina, N.V.; Khoromskaya, V.A.; Shiryaeva, G.V.

    1988-03-01

    The radiation behavior of (meth)acrylic esters of varying structure was studied. It was shown that in radiation polymerization, in contrast to thermal polymerization, the structure of the ester part can significantly affect the reaction rate and capacity for polymerization in the presence of oxygen. The experimental data are explained from the point of view of consideration of nonvalence effects of the substitutent on the reactivity of the double bond.

  20. Genetic mapping in the lignin-degrading basidiomycete Phanerochaete chrysosporium

    SciTech Connect

    Krejci, R. ); Homolka, L. )

    1991-01-01

    The basidiomycete Phanerochaete chrysosporium is commonly used as a model organism in studies concerned with lignin biodegradation. In further investigations of the enzymology and regulation of ligninolytic activity as well as the construction of industrially applicable strains for biotechnological processing of lignin and lignocellulose, the genetics of this fungus is of great interest. A method of meiotic segregation analysis based on recombinant selection in the homothallic basidiomycete Phanerochaete chrysosporium was developed. Using this method, we were able to reveal linkage relationships and to estimate recombination frequencies between seven mutations to auxotrophy. We detected two linkage groups, the first containing four and the second three of the seven mapped mutations.

  1. Polymerization Evaluation by Spectrophotometric Measurements.

    ERIC Educational Resources Information Center

    Dunach, Jaume

    1985-01-01

    Discusses polymerization evaluation by spectrophotometric measurements by considering: (1) association degrees and molar absorptivities; (2) association degrees and equilibrium constants; and (3) absorbance and equilibrium constants. (JN)

  2. Sustainable polymerizations in recoverable microemulsions.

    PubMed

    Chen, Zhenzhen; Yan, Feng; Qiu, Lihua; Lu, Jianmei; Zhou, Yinxia; Chen, Jiaxin; Tang, Yishan; Texter, John

    2010-03-16

    Free radical and atom-transfer radical polymerizations were conducted in monomer/ionic liquid microemulsions. After the polymerization and isolation of the resultant polymers, the mixture of the catalyst and ionic liquids (surfactant and continuous phase) can be recovered and reused, thereby dramatically improving the environmental sustainability of such chemical processing. The addition of monomer to recovered ionic liquid mixtures regenerates transparent, stable microemulsions that are ready for the next polymerization cycle upon addition of initiator. The method combines the advantages of IL recycling and microemulsion polymerization and minimizes environmental disposable effects from surfactants and heavy metal ions. PMID:20170175

  3. Continuous polymerization reactor

    SciTech Connect

    Wilt, M.S.

    1986-05-06

    A method is described for contacting olefinic monomer and initiator in a continuous polymerization process comprising of the steps of: creating three turbulent zones in a vessel; introducing the olefinic monomer into a first part of the periphery of each one of the three turbulent zones; introducing the initiator into a second part of the periphery of each one of the three turbulent zones, wherein the first part of the periphery of each one of the three turbulent zones is substantially diametrically opposed to the second part of the periphery of each one of the three turbulent zones respectively.

  4. Bimorphic polymeric photomechanical actuator

    NASA Technical Reports Server (NTRS)

    Sarkisov, Sergey S. (Inventor); Curley, Michael J. (Inventor); Adamovsky, Grigory (Inventor); Sarkisov, Jr., Sergey S. (Inventor); Fields, Aisha B. (Inventor)

    2006-01-01

    A bimorphic polymeric photomechanical actuator, in one embodiment using polyvinylidene fluoride (PVDF) as a photosensitive body, transmitting light over fiber optic cables, and controlling the shape and pulse duration of the light pulse to control movement of the actuator. Multiple light beams are utilized to generate different ranges of motion for the actuator from a single photomechanical body and alternative designs use multiple light beams and multiple photomechanical bodies to provide controlled movement. Actuator movement using one or more ranges of motion is utilized to control motion to position an actuating element in three dimensional space.

  5. Living olefin polymerization processes

    DOEpatents

    Schrock, Richard R.; Bauman, Robert

    2006-11-14

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  6. Living olefin polymerization processes

    DOEpatents

    Schrock, Richard R.; Baumann, Robert

    2003-08-26

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  7. Living olefin polymerization processes

    DOEpatents

    Schrock, R.R.; Baumann, R.

    1999-03-30

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  8. Living olefin polymerization processes

    DOEpatents

    Schrock, Richard R.; Baumann, Robert

    1999-01-01

    Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.

  9. Preparation and characterization of Lignin-graft-poly (ɛ-caprolactone) copolymers based on lignocellulosic butanol residue.

    PubMed

    Liu, Xiaohuan; Zong, Enmin; Jiang, Jinhua; Fu, Shenyuan; Wang, Jifu; Xu, Binbin; Li, Wenhuan; Lin, Xianzhi; Xu, Yuzhi; Wang, Chunpeng; Chu, Fuxiang

    2015-11-01

    In this paper, a "graft from" Ring-Opening Polymerization (ROP) technique was used to synthesize a lignin-graft-poly (ɛ-caprolactone) copolymer (BBL-g-PCL) using biobutanol lignin (BBL) as raw material recovered from lignocellulosic butanol residue. Polymerizations were carried out with various mass ratios of BBL and CL monomer ([BBL]/([BBL]+[CL])=1.0%, 5.0%, 10%, 20% and 40% (w/w)) to obtain BBL-g-PCL copolymers with different molecular weights, ranging from 367 to 8163gmol(-1). The grafting efficiency was preliminary evidenced by the long-term stability of dissolution of BBL-g-PCL in toluene. FT-IR and NMR analysis provided the further evidences for successful formation of BBL-g-PCL copolymer. The thermal properties of BBL-g-PCL copolymers were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). These results indicated that BBL-g-PCL copolymer had relatively good thermal stability. The static contact angle of BBL-g-PCL coating film reached to 80°. The surface functional groups and chemical composition of BBL-g-PCL copolymer was investigated in detail by X-ray photoelectron spectroscopy (XPS). The surface morphology of BBL-g-PCL copolymer was studied by Atomic force microscopy (AFM). Additionally, BBL-g-PCL coating film exhibited high absorption in the ultraviolet (UV) range, which could allow for applications in UV-blocking coatings, as well as the extents for the utilization of lignocellulosic butanol residue. PMID:26306414

  10. Identifying new lignin bioengineering targets: 1. Monolignol-substitute impacts on lignin formation and cell wall fermentability

    PubMed Central

    2010-01-01

    Background Recent discoveries highlighting the metabolic malleability of plant lignification indicate that lignin can be engineered to dramatically alter its composition and properties. Current plant biotechnology efforts are primarily aimed at manipulating the biosynthesis of normal monolignols, but in the future apoplastic targeting of phenolics from other metabolic pathways may provide new approaches for designing lignins that are less inhibitory toward the enzymatic hydrolysis of structural polysaccharides, both with and without biomass pretreatment. To identify promising new avenues for lignin bioengineering, we artificially lignified cell walls from maize cell suspensions with various combinations of normal monolignols (coniferyl and sinapyl alcohols) plus a variety of phenolic monolignol substitutes. Cell walls were then incubated in vitro with anaerobic rumen microflora to assess the potential impact of lignin modifications on the enzymatic degradability of fibrous crops used for ruminant livestock or biofuel production. Results In the absence of anatomical constraints to digestion, lignification with normal monolignols hindered both the rate and extent of cell wall hydrolysis by rumen microflora. Inclusion of methyl caffeate, caffeoylquinic acid, or feruloylquinic acid with monolignols considerably depressed lignin formation and strikingly improved the degradability of cell walls. In contrast, dihydroconiferyl alcohol, guaiacyl glycerol, epicatechin, epigallocatechin, and epigallocatechin gallate readily formed copolymer-lignins with normal monolignols; cell wall degradability was moderately enhanced by greater hydroxylation or 1,2,3-triol functionality. Mono- or diferuloyl esters with various aliphatic or polyol groups readily copolymerized with monolignols, but in some cases they accelerated inactivation of wall-bound peroxidase and reduced lignification; cell wall degradability was influenced by lignin content and the degree of ester group hydroxylation

  11. Organometallic Polymeric Conductors

    NASA Technical Reports Server (NTRS)

    1997-01-01

    For aerospace applications, the use of polymers can result in tremendous weight savings over metals. Suitable polymeric materials for some applications like EMI shielding, spacecraft grounding, and charge dissipation must combine high electrical conductivity with long-term environmental stability, good processability, and good mechanical properties. Recently, other investigators have reported hybrid films made from an electrically conductive polymer combined with insulating polymers. In all of these instances, the films were prepared by infiltrating an insulating polymer with a precursor for a conductive polymer (either polypyrrole or polythiophene), and oxidatively polymerizing the precursor in situ. The resulting composite films have good electrical conductivity, while overcoming the brittleness inherent in most conductive polymers. The highest conductivities reported (approximately 4/Scm) were achieved with polythiophene in a polystyrene host polymer. The best films using a polyamide as base polymer were four orders of magnitude less conductive than the polystyrene films. The authors suggested that this was because polyimides were unable to swell sufficiently for infiltration of monomer as in the polystyrene. It was not clear, however, if the different conductivities obtained were merely the result of differing oxidation conditions. Oxidation time, temperature and oxidant concentration varied widely among the studies.

  12. Solvent-Driven Preferential Association of Lignin with Regions of Crystalline Cellulose in Molecular Dynamics Simulation

    SciTech Connect

    Lindner, Benjamin; Petridis, Loukas; Schulz, Roland; Smith, Jeremy C

    2013-01-01

    The precipitation of lignin onto cellulose after pretreatment of lignocellulosic biomass is an obstacle to economically viable cellulosic ethanol production. Here, 750 ns nonequilibrium molecular dynamics simulations are reported of a system of lignin and cellulose in aqueous solution. Lignin is found to strongly associate with itself and the cellulose. However, noncrystalline regions of cellulose are observed to have a lower tendency to associate with lignin than crystalline regions, and this is found to arise from stronger hydration of the noncrystalline chains. The results suggest that the recalcitrance of crystalline cellulose to hydrolysis arises not only from the inaccessibility of inner fibers but also due to the promotion of lignin adhesion.

  13. Chemicals from Lignin by Catalytic Fast Pyrolysis, from Product Control to Reaction Mechanism.

    PubMed

    Ma, Zhiqiang; Custodis, Victoria; Hemberger, Patrick; Bährle, Christian; Vogel, Frédéric; Jeschk, Gunnar; van Bokhoven, Jeroen A

    2015-01-01

    Conversion of lignin into renewable and value-added chemicals by thermal processes, especially pyrolysis, receives great attention. The products may serve as feedstock for chemicals and fuels and contribute to the development of a sustainable society. However, the application of lignin conversion is limited by the low selectivity from lignin to the desired products. The opportunities for catalysis to selectively convert lignin into useful chemicals by catalytic fast pyrolysis and our efforts to elucidate the mechanism of lignin pyrolysis are discussed. Possible research directions will be identified. PMID:26598403

  14. Lignin-derived thermoplastic co-polymers and methods of preparation

    DOEpatents

    Naskar, Amit K.; Saito, Tomonori; Pickel, Joseph M.; Baker, Frederick S.; Eberle, Claude Clifford; Norris, Robert E.; Mielenz, Jonathan Richard

    2014-06-10

    The present invention relates to a crosslinked lignin comprising a lignin structure having methylene or ethylene linking groups therein crosslinking between phenyl ring carbon atoms, wherein said crosslinked lignin is crosslinked to an extent that it has a number-average molecular weight of at least 10,000 g/mol, is melt-processible, and has either a glass transition temperature of at least 100.degree. C., or is substantially soluble in a polar organic solvent or aqueous alkaline solution. Thermoplastic copolymers containing the crosslinked lignin are also described. Methods for producing the crosslinked lignin and thermoplastic copolymers are also described.

  15. Graphitic biocarbon from metal-catalyzed hydrothermal carbonization of lignin

    DOE PAGESBeta

    Demir, Muslum; Kahveci, Zafer; Aksoy, Burak; Palapati, Naveen K. R.; Subramanian, Arunkumar; Cullinan, Harry T.; El-Kaderi, Hani M.; Harris, Charles T.; Gupta, Ram B.

    2015-10-09

    Lignin is a high-volume byproduct from the pulp and paper industry and is currently burned to generate electricity and process heat. Moreover, the industry has been searching for high value-added uses of lignin to improve the process economics. In addition, battery manufacturers are seeking nonfossil sources of graphitic carbon for environmental sustainability. In our work, lignin (which is a cross-linked polymer of phenols, a component of biomass) is converted into graphitic porous carbon using a two-step conversion. Lignin is first carbonized in water at 300 °C and 1500 psi to produce biochar, which is then graphitized using a metal nitratemore » catalyst at 900–1100 °C in an inert gas at 15 psi. Graphitization effectiveness of three different catalysts—iron, cobalt, and manganese nitrates—is examined. The product is analyzed for morphology, thermal stability, surface properties, and electrical conductivity. Both temperature and catalyst type influenced the degree of graphitization. A good quality graphitic carbon was obtained using catalysis by Mn(NO3)2 at 900 °C and Co(NO3)2 at 1100 °C.« less

  16. EVALUATION OF PRISTINE LIGNIN FOR HAZARDOUS WASTE TREATMENT

    EPA Science Inventory

    A feasibility study was conducted to assess the utilization of lignin, isolated from a steam-exploded hardwood (Tulip poplar) with 95% ethanol and 0.1n NaOH, as a potential adsorbent for hazardous waste treatment. Eight organic compounds and two heavy metals were selected to allo...

  17. Lignin modification to improve sorghum for cellulosic and thermal bioenergy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Modifying lignin content and composition are major targets for bioenergy feedstock improvement for both cellulosic and thermal bioenergy conversion. Sorghum (Sorghum bicolor) is currently being developed as a dedicated bio-energy feedstock. Our goals are to improve sorghum biomass for both biochemic...

  18. Laccase-mediator catalyzed conversion of model lignin compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Laccases play an important role in the biological breakdown of lignin and have great potential in the deconstruction of lignocellulosic feedstocks. We examined a variety of laccases, both commercially prepared and crude extracts, for their ability to oxidize three model lignol compounds (p-coumaryl...

  19. Switchgrass contains two cinnamyl alcohol dehydrogenases involved in lignin formation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Switchgrass (Panicum virgatum L.) is a perennial polyploid grass with considerable potential as a bioenergy species. Many aspects of its biology and cell wall development are yet to be elucidated. Lignin content of cell walls is one of the key determinants of biomass quality and is a negative trai...

  20. Wood degradation under UV irradiation: A lignin characterization.

    PubMed

    Cogulet, Antoine; Blanchet, Pierre; Landry, Véronic

    2016-05-01

    The photodegradation of white spruce by artificial ageing was studied by several techniques: colourimetry, FTIR-ATR and FT-Raman spectroscopy. Samples were exposed at a xenon lamp for 2000h. Two distinct colour changes were found by colourimetric analysis, yellowing and silvering. These colour modifications indicate the formation of chromophoric structures which supports previous FTIR-ATR experiments. The degradation of lignin to generate the first chromophoric group for yellowing and then the appearance of surface layer cellulose. New carbonyl compounds conjugated with double bond at 1615cm(-1) are probably the second chromophoric group. The crystallinity index was also calculated and showed an increase of cellulose crystallinity by prior degradation of amorphous cellulose. The FT-Raman analysis confirms the wood sensitivity to photodegradation but the most remarkable results is the increase of fluorescence as a function of time. In softwood lignin, the compound able to produce fluorescence is a free rotating 5-5' linkage of one biphenyl structure. At native state these linkages are not free rotating, this phenomenon means the release of 5-5' linkage of lignin structure by cleavage of both α carbon linkages (Norrish type I reaction). These data confirm also the photosensitivity of α and β carbon in lignin and the resistance of 5-5' linkages. PMID:26974579

  1. Incorporation of Monolignol Conjugates into Lignin for Improved Processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lignin remains one of the most significant barriers to the efficient utilization of cellulosic substrates, either for pulping or for biofuels production. Now that monomer substitution in the lignification process is now well authenticated in various transgenic plants, it is opportune to begin explor...

  2. Screening heterogenous catalysts for the pyrolysis of lignin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The pyrolytic conversion of pure lignin at 600°C in flowing helium over five catalysts is described and compared to the control bed material, sand. Product distribution as char, liquid and gas are described as well as the composition of the liquid and gas fractions. The catalysts examined were HZS...

  3. EVIDENCE FOR CLEAVAGE OF LIGNIN BY A BROWN ROT FUNGUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodegradation by brown-rot fungi is quantitatively one of the most important fates of lignocellulose in nature. It has long been thought that these fungi do not degrade lignin significantly, and that their activities on this abundant aromatic biopolymer are limited to minor oxidative modifications....

  4. Catalytic pyrolysis-GC/MS of lignin from several sources

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lignin from four different sources extracted by various methods were pyrolyzed at 650 degree C using analytical pyrolysis methods, py-GC/MS. Pyrolysis was carried out in the absence and presence of two heterogeneous catalysts , an acidic zeolite (HZSM-5) catalyst and a mixed metal oxide catalyst (Co...

  5. Laccase-Mediator catalyzed conversion of model Lignin compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Laccases play an important role in the biological breakdown of lignin and have great potential in the deconstruction of lignocellulosic feedstocks. We examined a variety of laccases, both commercially prepared and crude extracts, for their ability to oxidize three model lignol compounds (p-coumaryl...

  6. Laccase-mediator catalyzed conversion of model lignin compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Identifying suitable reaction conditions remains an important task in the development of practical enzyme catalysts. Laccases play an important role in the biological break down of lignin and have great potential in the deconstruction of lignocellulosic feedstocks. We examined 16 laccases, both comm...

  7. Graphitic biocarbon from metal-catalyzed hydrothermal carbonization of lignin

    SciTech Connect

    Demir, Muslum; Kahveci, Zafer; Aksoy, Burak; Palapati, Naveen K. R.; Subramanian, Arunkumar; Cullinan, Harry T.; El-Kaderi, Hani M.; Harris, Charles T.; Gupta, Ram B.

    2015-10-09

    Lignin is a high-volume byproduct from the pulp and paper industry and is currently burned to generate electricity and process heat. Moreover, the industry has been searching for high value-added uses of lignin to improve the process economics. In addition, battery manufacturers are seeking nonfossil sources of graphitic carbon for environmental sustainability. In our work, lignin (which is a cross-linked polymer of phenols, a component of biomass) is converted into graphitic porous carbon using a two-step conversion. Lignin is first carbonized in water at 300 °C and 1500 psi to produce biochar, which is then graphitized using a metal nitrate catalyst at 900–1100 °C in an inert gas at 15 psi. Graphitization effectiveness of three different catalysts—iron, cobalt, and manganese nitrates—is examined. The product is analyzed for morphology, thermal stability, surface properties, and electrical conductivity. Both temperature and catalyst type influenced the degree of graphitization. A good quality graphitic carbon was obtained using catalysis by Mn(NO3)2 at 900 °C and Co(NO3)2 at 1100 °C.

  8. Recent Development in Chemical Depolymerization of Lignin: A Review

    DOE PAGESBeta

    Wang, Hai; Tucker, Melvin; Ji, Yun

    2013-01-01

    This article reviewed recent development of chemical depolymerization of lignins. There were five types of treatment discussed, including base-catalyzed, acid-catalyzed, metallic catalyzed, ionic liquids-assisted, and supercritical fluids-assisted lignin depolymerizations. The methods employed in this research were described, and the important results were marked. Generally, base-catalyzed and acid-catalyzed methods were straightforward, but the selectivity was low. The severe reaction conditions (high pressure, high temperature, and extreme pH) resulted in requirement of specially designed reactors, which led to high costs of facility and handling. Ionic liquids, and supercritical fluids-assisted lignin depolymerizations had high selectivity, but the high costs of ionic liquids recyclingmore » and supercritical fluid facility limited their applications on commercial scale biomass treatment. Metallic catalyzed depolymerization had great advantages because of its high selectivity to certain monomeric compounds and much milder reaction condition than base-catalyzed or acid-catalyzed depolymerizations. It would be a great contribution to lignin conversion if appropriate catalysts were synthesized.« less

  9. LIGNIN DEGRADATION IN GRASSLAND, FOREST, AND SHRUB-STEPPE SOILS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lignin decomposition was studied in soils from research plots in 5 locations in the US: restored tallgrass prairie, farmland (grain), semiarid shrub-steppe, and loblolly pine and Douglas fir forests. Soils were amended with 14C- lignocellulose and incubated for 6 months during which total- and 14C-C...

  10. Process for conversion of lignin to reformulated, partially oxygenated gasoline

    DOEpatents

    Shabtai, Joseph S.; Zmierczak, Wlodzimierz W.; Chornet, Esteban

    2001-01-09

    A high-yield process for converting lignin into reformulated, partially oxygenated gasoline compositions of high quality is provided. The process is a two-stage catalytic reaction process that produces a reformulated, partially oxygenated gasoline product with a controlled amount of aromatics. In the first stage of the process, a lignin feed material is subjected to a base-catalyzed depolymerization reaction, followed by a selective hydrocracking reaction which utilizes a superacid catalyst to produce a high oxygen-content depolymerized lignin product mainly composed of alkylated phenols, alkylated alkoxyphenols, and alkylbenzenes. In the second stage of the process, the depolymerized lignin product is subjected to an exhaustive etherification reaction, optionally followed by a partial ring hydrogenation reaction, to produce a reformulated, partially oxygenated/etherified gasoline product, which includes a mixture of substituted phenyl/methyl ethers, cycloalkyl methyl ethers, C.sub.7 -C.sub.10 alkylbenzenes, C.sub.6 -C.sub.10 branched and multibranched paraffins, and alkylated and polyalkylated cycloalkanes.

  11. Coating of plasma polymerized film

    NASA Technical Reports Server (NTRS)

    Morita, S.; Ishibashi, S.

    1980-01-01

    Plasma polymerized thin film coating and the use of other coatings is suggested for passivation film, thin film used for conducting light, and solid body lubrication film of dielectrics of ultra insulators for electrical conduction, electron accessories, etc. The special features of flow discharge development and the polymerized film growth mechanism are discussed.

  12. Flocculation of wheat straw soda lignin by hemoglobin and chicken blood: Effects of cationic polymer or calcium chloride

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flocculation can be used to separate non-sulfonated lignin from base hydrolyzed biomass. In the industrial process, the lignin is isolated by filtration and washed with water. Some of the lignin is lost in the wash water, and flocculation can be used to recover this lignin. Several ways of enhanc...

  13. Hydrotreating Pyrolytic Lignin to Produce a Refinery Feedstock (Poster)

    SciTech Connect

    French, R. J.

    2013-09-01

    Fast pyrolysis of biomass followed by water separation to produce pyrolytic lignin and hydrotreating of the lignin could be used to produce a stable volatile low-oxygen intermediate liquid. Such a liquid could be converted into a finished motor-fuel in a refinery, taking advantage of the existing infrastructure and economies of scale of refineries. Hydrotreating just the lignin would consume less hydrogen while preserving about half of the energy of the original oil. The aqueous by-products could be reformed to produce the needed hydrogen and would contain much of the unwanted acids and unstable oxygenates. To assess such intermediate liquids, several pyrolytic lignins were prepared by mixing pyrolysis oil with water at 1:1 and 3:1 ratios. The carboxylic acidity in the pyrolytic lignin was reduced to 24 and 10 mg-KOH/g-lignin compared to 81 in the whole oil. These lignins were hydrotreated using Ni-Mo(S)/alumina, Pt/char, or Pd/C(activated) in a semi-batch 1 L stirred autoclave. The oil was stabilized under hydrogen at 150-280 degrees C, then water and light organics were removed by partial depressurization. Hydrodeoxygenation was then performed at 340-400 degrees C. Total pressure was controlled at 70 or 170 bar with hydrogen gas. Organic liquid yields of 39-56% were obtained. For many experiments the organic oxygen content was <7%, acidity was < 7 mg-KOH/g-oil, the volatility was greater than or equal to 94% and, on a carbon basis, the total yield of organic products miscible in hydrocarbons at a 1:10 ratio was over 50%. These properties are probably acceptable to a refinery.The residual liquids left in the reactor at the end of the experiment comprised 60-85% of the organic-phase product while the rest was condensate. 13C-NMR of the residual liquids showed that they were 50-80% aliphatic. 13C-NMR coupled with GC-MS identified phenolic compounds as the main oxygenates in most residual liquids.

  14. Effect of different isolation methods on structure and properties of lignin from valonea of Quercus variabilis.

    PubMed

    Yang, Lina; Wang, Dongmei; Zhou, Dan; Zhang, Yawei

    2016-04-01

    Valonea of Quercus variabilis Blume, an abundant feedstock in China, can be used for tannin. However, there are little studies about lignin from this material. The present study aimed at lignin from the valonea: (1) Ethanol lignin (EL), alkali lignin (AL), milled wood lignin (MWL) and enzyme hydrolysis lignin (EHL) were prepared from the valonea of Q.variabilis Blume. (2) The effect of different isolation processes on the lignin chemical and physical features were studied by UV-vis, FT-IR, GPC, TG and (1)H NMR. (3) Antioxidant activities of four lignin preparations were evaluated by DPPH, ABTS and FRAP assays. The results showed that the valonea of Q. variabilis contained mass lignin and four lignin preparations were GSH-type with little differences. The MWL contained the least functional groups (1.75 mmol/g MeO, 0.87 mmol/g ArOH and 1.27 mmol/g AlkOH), the poorest thermostability (onset degradation temperature=111°C, maximum rate of degradation=268°C) and the highest antioxidant activity. The EHL had the highest molecular weight (Mw=1,429 g/mol; Mn=746.18 g/mol). This study provided a theoretical basis for the development and utilization of lignin from the valonea of Q. variabilis. PMID:26772919

  15. Structural Changes of Lignin after Liquid Hot Water Pretreatment and Its Effect on the Enzymatic Hydrolysis.

    PubMed

    Wang, Wen; Zhuang, Xinshu; Yuan, Zhenhong; Qi, Wei; Yu, Qiang; Wang, Qiong

    2016-01-01

    During liquid hot water (LHW) pretreatment, lignin is mostly retained in the pretreated biomass, and the changes in the chemical and structural characteristics of lignin should probably refer to re-/depolymerization, solubilization, or glass transition. The residual lignin could influence the effective enzymatic hydrolysis of cellulose. The pure lignin was used to evaluate the effect of LHW process on its structural and chemical features. The surface morphology of LHW-treated lignin observed with the scanning electron microscopy (SEM) was more porous and irregular than that of untreated lignin. Compared to the untreated lignin, the surface area, total pore volume, and average pore size of LHW-treated lignin tested with the Brunner-Emmet-Teller (BET) measurement were increased. FTIR analysis showed that the chemical structure of lignin was broken down in the LHW process. Additionally, the impact of untreated and treated lignin on the enzymatic hydrolysis of cellulose was also explored. The LHW-treated lignin had little impact on the cellulase adsorption and enzyme activities and somehow could improve the enzymatic hydrolysis of cellulose. PMID:27563678

  16. Structural Changes of Lignin after Liquid Hot Water Pretreatment and Its Effect on the Enzymatic Hydrolysis

    PubMed Central

    Zhuang, Xinshu; Qi, Wei; Yu, Qiang; Wang, Qiong

    2016-01-01

    During liquid hot water (LHW) pretreatment, lignin is mostly retained in the pretreated biomass, and the changes in the chemical and structural characteristics of lignin should probably refer to re-/depolymerization, solubilization, or glass transition. The residual lignin could influence the effective enzymatic hydrolysis of cellulose. The pure lignin was used to evaluate the effect of LHW process on its structural and chemical features. The surface morphology of LHW-treated lignin observed with the scanning electron microscopy (SEM) was more porous and irregular than that of untreated lignin. Compared to the untreated lignin, the surface area, total pore volume, and average pore size of LHW-treated lignin tested with the Brunner-Emmet-Teller (BET) measurement were increased. FTIR analysis showed that the chemical structure of lignin was broken down in the LHW process. Additionally, the impact of untreated and treated lignin on the enzymatic hydrolysis of cellulose was also explored. The LHW-treated lignin had little impact on the cellulase adsorption and enzyme activities and somehow could improve the enzymatic hydrolysis of cellulose. PMID:27563678

  17. Correlation between lignin physicochemical properties and inhibition to enzymatic hydrolysis of cellulose.

    PubMed

    Yang, Qiang; Pan, Xuejun

    2016-06-01

    Using isolated organosolv lignins from hardwood poplar and softwood lodgepole pine with varied physicochemical properties (molecular weight, aliphatic hydroxyl, phenolic hydroxyl, and hydrophobicity), the inhibitory effect of the lignins on enzymatic hydrolysis of cellulose was investigated and the relationship between lignin properties and the inhibitory effect was elucidated. The results indicated that the lignin inhibition to enzymatic hydrolysis of cellulose was closely related to the hydrophobicity and the phenolic hydroxyl groups of the lignin. The overall hydrophobicity of the lignin quantified by contact angle could serve as a predictor of the inhibitory effect of lignin. Hydrophilic modification of the lignin by carboxylation and sulfonation reduced the hydrophobicity by 22-30% and thereby removed the lignin inhibition by 76-96%. Phenolic hydroxyl group was a crucial factor affecting the inhibitory effect of lignin. Blocking free phenolic hydroxyl group by chemical reaction such as hydroxypropylation significantly (65-91%) reduced the inhibitory effect of lignin. Biotechnol. Bioeng. 2016;113: 1213-1224. © 2015 Wiley Periodicals, Inc. PMID:26666388

  18. [Phenolic foam prepared by lignin from a steam-explosion derived biorefinery of corn stalk].

    PubMed

    Wang, Guanhua; Chen, Hongzhang

    2014-06-01

    To increase the integral economic effectiveness, biorefineries of lignocellulosic materials should not only utilize carbohydrates hydrolyzed from cellulose and hemicellulose but also use lignin. We used steam-exploded corn stalk as raw materials and optimized the temperature and alkali concentration in the lignin extraction process to obtain lignin liquor with higher yield and purity. Then the concentrated lignin liquor was used directly to substitute phenol for phenolic foam preparation and the performances of phenolic foam were characterized by microscopic structure analysis, FTIR, compression strength and thermal conductivity detection. The results indicated that, when steam-exploded corn stalk was extracted at 120 degrees C for 2 h by 1% NaOH with a solid to liquid ratio of 1:10, the extraction yield of lignin was 79.67%. The phenolic foam prepared from the concentrated lignin liquor showed higher apparent density and compression strength with the increasing substitution rate of lignin liquor. However, there were not significant differences of thermal conductivity and flame retardant properties by the addition of lignin, which meant that the phenolic foam substituted by lignin liquor was approved for commercial application. This study, which uses alkali-extracted lignin liquor directly for phenolic foam preparation, provides a relatively simple way for utilization of lignin and finally increases the overall commercial operability ofa lignocellulosic biorefinery derived by steam explosion. PMID:25212007

  19. Bio-inspired MOF-based Catalysts for Lignin Valorization.

    SciTech Connect

    Allendorf, Mark D.; Stavila, Vitalie; Ramakrishnan, Parthasarathi; Davis, Ryan Wesley

    2014-09-01

    Lignin is a potentially plentiful source of renewable organics, with %7E50Mtons/yr produced by the pulp/paper industry and 200-300 Mtons/yr projected production by a US biofuels industry. This industry must process approximately 1 billion tons of biomass to meet the US Renewable Fuel goals. However, there are currently no efficient processes for converting lignin to value-added chemicals and drop-in fuels. Lignin is therefore an opportunity for production of valuable renewable chemicals, but presents staggering technical and economic challenges due to the quantities of material involved and the strong chemical bonds comprising this polymer. Aggressive chemistries and high temperatures are required to degrade lignin without catalysts. Moreover, chemical non-uniformity among lignins leads to complex product mixtures that tend to repolymerize. Conventional petrochemical approaches (pyrolysis, catalytic cracking, gasification) are energy intensive (400-800 degC), require complicated separations, and remove valuable chemical functionality. Low-temperature (25-200 degC) alternatives are clearly desirable, but enzymes are thermally fragile and incompatible with liquid organic compounds, making them impractical for large-scale biorefining. Alternatively, homogeneous catalysts, such as recently developed vanadium complexes, must be separated from product mixtures, while many heterogenous catalysts involve costly noble metals. The objective of this project is to demonstrate proof of concept that an entirely new class of biomimetic, efficient, and industrially robust synthetic catalysts based on nanoporous Metal- Organic Frameworks (MOFs) can be developed. Although catalytic MOFs are known, catalysis of bond cleavage reactions needed for lignin degradation is completely unexplored. Thus, fundamental research is required that industry and most sponsoring agencies are currently unwilling to undertake. We introduce MOFs infiltrated with titanium and nickel species as catalysts

  20. Consolidated bioprocessing of Populus using Clostridium (Ruminiclostridium) thermocellum: a case study on the impact of lignin composition and structure

    DOE PAGESBeta

    Dumitrache, Alexandru; Akinosho, Hannah; Rodriguez, Miguel; Meng, Xianzhi; Yoo, Chang Geun; Natzke, Jace; Engle, Nancy L.; Sykes, Robert W.; Tschaplinski, Timothy J.; Muchero, Wellington; et al

    2016-02-04

    Background: Higher ratios of syringyl-to-guaiacyl (S/G) lignin components of Populus were shown to improve sugar release by enzymatic hydrolysis using commercial blends. Cellulolytic microbes are often robust biomass hydrolyzers and may offer cost advantages; however, it is unknown whether their activity can also be significantly influenced by the ratio of different monolignol types in Populus biomass. Hydrolysis and fermentation of autoclaved, but otherwise not pretreated Populus trichocarpa by Clostridium thermocellum ATCC 27405 was compared using feedstocks that had similar carbohydrate and total lignin contents but differed in S/G ratios. Results: Populus with an S/G ratio of 2.1 was converted moremore » rapidly and to a greater extent compared to similar biomass that had a ratio of 1.2. For either microbes or commercial enzymes, an approximate 50% relative difference in total solids solubilization was measured for both biomasses, which suggests that the differences and limitations in the microbial breakdown of lignocellulose may be largely from the enzymatic hydrolytic process. Unexpectedly, the reduction in glucan content per gram solid in the residual microbially processed biomass was similar (17–18%) irrespective of S/G ratio, pointing to a similar mechanism of solubilization that proceeded at different rates. Fermentation metabolome testing did not reveal the release of known biomass-derived alcohol and aldehyde inhibitors that could explain observed differences in microbial hydrolytic activity. Biomass-derived p-hydroxybenzoic acid was up to ninefold higher in low S/G ratio biomass fermentations, but was not found to be inhibitory in subsequent test fermentations. Cellulose crystallinity and degree of polymerization did not vary between Populus lines and had minor changes after fermentation. However, lignin molecular weights and cellulose accessibility determined by Simons’ staining were positively correlated to the S/G content. Conclusions: Higher

  1. Selective removal of phenolic lignin derivatives enables sugars recovery from wood prehydrolysis liquor with remarkable yield.

    PubMed

    Wang, Zhaojiang; Jiang, Jungang; Wang, Xiaojun; Fu, Yingjuan; Li, Zongquan; Zhang, Fengshan; Qin, Menghua

    2014-12-01

    The specific elimination of lignin derivatives from wood hydrolysate without sugar loss has great practical significance to biorefinery and bioenergy. In the present study, a process consisting of calcium hydroxide and anion exchange resin treatments was developed for the purpose of selective removal of lignin from wood prehydrolysis liquor (PHL). Particular emphasis was made on the ionization of phenolic lignin, and the subsequent binding to metallic salts. It was observed that phenolic hydroxyl groups (PhOH) in lignin played an important role in lignin removal. The results showed that up to 95.2% lignin was removed from PHL with 78.8% sugar recovery. This suggested that the proposed process is highly specific to lignin, and therefore can be envisaged as a great contribution to wood-sugar production or bioenergy conversion. PMID:25463800

  2. Predicting enzyme adsorption to lignin films by calculating enzyme surface hydrophobicity.

    PubMed

    Sammond, Deanne W; Yarbrough, John M; Mansfield, Elisabeth; Bomble, Yannick J; Hobdey, Sarah E; Decker, Stephen R; Taylor, Larry E; Resch, Michael G; Bozell, Joseph J; Himmel, Michael E; Vinzant, Todd B; Crowley, Michael F

    2014-07-25

    The inhibitory action of lignin on cellulase cocktails is a major challenge to the biological saccharification of plant cell wall polysaccharides. Although the mechanism remains unclear, hydrophobic interactions between enzymes and lignin are hypothesized to drive adsorption. Here we evaluate the role of hydrophobic interactions in enzyme-lignin binding. The hydrophobicity of the enzyme surface was quantified using an estimation of the clustering of nonpolar atoms, identifying potential interaction sites. The adsorption of enzymes to lignin surfaces, measured using the quartz crystal microbalance, correlates to the hydrophobic cluster scores. Further, these results suggest a minimum hydrophobic cluster size for a protein to preferentially adsorb to lignin. The impact of electrostatic contribution was ruled out by comparing the isoelectric point (pI) values to the adsorption of proteins to lignin surfaces. These results demonstrate the ability to predict enzyme-lignin adsorption and could potentially be used to design improved cellulase cocktails, thus lowering the overall cost of biofuel production. PMID:24876380

  3. Modifying lignin to improve bioenergy feedstocks: strengthening the barrier against pathogens?†

    PubMed Central

    Sattler, Scott E.; Funnell-Harris, Deanna L.

    2013-01-01

    Lignin is a ubiquitous polymer present in cell walls of all vascular plants, where it rigidifies and strengthens the cell wall structure through covalent cross-linkages to cell wall polysaccharides. The presence of lignin makes the cell wall recalcitrant to conversion into fermentable sugars for bioenergy uses. Therefore, reducing lignin content and modifying its linkages have become major targets for bioenergy feedstock development through either biotechnology or traditional plant breeding. In addition, lignin synthesis has long been implicated as an important plant defense mechanism against pathogens, because lignin synthesis is often induced at the site of pathogen attack. This article explores the impact of lignin modifications on the susceptibility of a range of plant species to their associated pathogens, and the implications for development of feedstocks for the second-generation biofuels industry. Surprisingly, there are some instances where plants modified in lignin synthesis may display increased resistance to associated pathogens, which is explored in this article. PMID:23577013

  4. Predicting Enzyme Adsorption to Lignin Films by Calculating Enzyme Surface Hydrophobicity*

    PubMed Central

    Sammond, Deanne W.; Yarbrough, John M.; Mansfield, Elisabeth; Bomble, Yannick J.; Hobdey, Sarah E.; Decker, Stephen R.; Taylor, Larry E.; Resch, Michael G.; Bozell, Joseph J.; Himmel, Michael E.; Vinzant, Todd B.; Crowley, Michael F.

    2014-01-01

    The inhibitory action of lignin on cellulase cocktails is a major challenge to the biological saccharification of plant cell wall polysaccharides. Although the mechanism remains unclear, hydrophobic interactions between enzymes and lignin are hypothesized to drive adsorption. Here we evaluate the role of hydrophobic interactions in enzyme-lignin binding. The hydrophobicity of the enzyme surface was quantified using an estimation of the clustering of nonpolar atoms, identifying potential interaction sites. The adsorption of enzymes to lignin surfaces, measured using the quartz crystal microbalance, correlates to the hydrophobic cluster scores. Further, these results suggest a minimum hydrophobic cluster size for a protein to preferentially adsorb to lignin. The impact of electrostatic contribution was ruled out by comparing the isoelectric point (pI) values to the adsorption of proteins to lignin surfaces. These results demonstrate the ability to predict enzyme-lignin adsorption and could potentially be used to design improved cellulase cocktails, thus lowering the overall cost of biofuel production. PMID:24876380

  5. In vitro depolymerization of lignin by manganese peroxidase of Phanerochaete chrysosporium

    SciTech Connect

    Wariishi, H.; Valli, K.; Gold, M.H. )

    1991-04-15

    Homogeneous manganese peroxidase catalyzed the in vitro partial depolymerization of four different {sup 14}C-labeled synthetic lignin preparations. Gel permeation profiles demonstrated significant depolymerization of {sup 14}C-sidechain-labeled syringyl lignin, a {sup 14}C-sidechain-labeled syringyl-guaiacyl copolymer (angiosperm lignin), and depolymerization of {sup 14}C-sidechain- and {sup 14}C-ring-labeled guaiacyl lignins (gymnosperm lignin). 3,5-Dimethoxy-1,4-benzo-quinone, 3,5-dimethoxy-1,4-hydroquinone, and syringylaldehyde were identified as degradation products of the syringyl and syringyl-guaiacyl lignins. These results suggest that manganese peroxidase plays a significant role in the depolymerization of lignin by Phanerochaete chrysosporium.

  6. A study of poplar organosolv lignin after melt rheology treatment as carbon fiber precursors

    DOE PAGESBeta

    Sun, Qining; Khunsupat, Ratayakorn; Akato, Kokouvi; Tao, Jingming; Labbe, Nicole; Gallego, Nidia C.; Bozell, Joseph J.; Rials, Timothy G.; Tuskan, Gerald A.; Tschaplinski, Timothy J.; et al

    2016-06-16

    Lignins from various poplar genotypes were isolated by using organosolv fractionation and subjected to rheological treatment at various temperatures. Physicochemical characterization of the lignin variants shows a broad distribution of glass transition temperatures, melt viscosity, and pyrolysis char residues. Rheological treatment at 170 °C induces lignin repolymerization accompanied with an increase in condensed linkages, molecular weights, and viscosities. In contrast, rheology testing at 190 °C results in the decrease in lignin aliphatic and phenolic hydroxyl groups, β-O-aryl ether linkages, molecular weights, and viscosity values. Lignin under air cooling generates more oxygenated and condensed compounds, but lower amounts of ether linkagesmore » than lignin cooled under nitrogen. Here, lignin with a lower syringyl/guaiacyl ratio tends to form more cross-linkages along with higher viscosity values, higher molecular weight and larger amounts of condensed bonds.« less

  7. Combination of lignin and l-lactide towards grafted copolymers from lignocellulosic butanol residue.

    PubMed

    Zong, Enmin; Jiang, Jinhua; Liu, Xiaohuan; Fu, Shenyuan; Xu, Yuzhi; Chu, Fuxiang

    2016-05-01

    A series of BBL-graft-poly (l-lactide) copolymers were synthesized via ring-opening polymerization (ROP) of l-lactide (l-LA) with a biobutanol lignin (BBL) initiator and a triazabicyclodecene (TBD) catalyst under free-solvent at 135°C. By manipulating the mass ratio of BBL/LLA, BBL-g-PLLA copolymers with tunable number-average molecular weight (Mn) (2544-7033gmol(-1)) were obtained. The chemical structure of PLLA chains was identifiable by FT-IR, (1)H NMR and (13)C NMR spectroscopies, in combination with UV-vis spectra to provide support for the existence of the BBL in the copolymer. This provided solid evidence for the successful synthesis of BBL-g-PLLA copolymer. The thermal properties and surface characterization of BBL-g-PLLA copolymers were different from those of linear PLLA. Furthermore, the BBL-g-PLLA copolymer film showed good absorption capacity in the UV region and high transparency in the visible light region, which was expected to find significant applications in UV-protective coating film. PMID:26776871

  8. Characterization of carbon nanofiber mats produced from electrospun lignin-g-polyacrylonitrile copolymer.

    PubMed

    Youe, Won-Jae; Lee, Soo-Min; Lee, Sung-Suk; Lee, Seung-Hwan; Kim, Yong Sik

    2016-01-01

    The graft copolymerization of acrylonitrile (AN) onto methanol-soluble kraft lignin (ML) was achieved through a two-step process in which AN was first polymerized with an α,α'-azobisisobutyronitrile initiator, followed by radical coupling with activated ML. A carbon nanofiber material was obtained by electrospinning a solution of this copolymer in N,N-dimethylformamide, then subjecting it to a heat treatment including thermostabilization at 250°C and subsequent carbonization at 600-1400°C. Increasing the carbonization temperature was found to increase the carbon content of the resulting carbon nanofibers from 70.5 to 97.1%, which had the effect of increasing their tensile strength from 35.2 to 89.4 MPa, their crystallite size from 13.2 to 19.1 nm, and their electrical conductivity from ∼0 to 21.3 Scm(-1). The morphology of the mats, in terms of whether they experienced beading or not, was found to be dependent on the concentration of the initial electrospinning solution. From these results, it is proposed that these mats could provide the basis for a new class of carbon fiber material. PMID:26459170

  9. Peroxidase 4 is involved in syringyl lignin formation in Arabidopsis thaliana.

    PubMed

    Fernández-Pérez, Francisco; Vivar, Tamara; Pomar, Federico; Pedreño, María A; Novo-Uzal, Esther

    2015-03-01

    Syringyl lignins result from the oxidative polymerization of sinapyl alcohol in a reaction mediated by syringyl (basic) peroxidases. Several peroxidases have been identified in the genome of Arabidopsis thaliana as close homologues to ZePrx, the best characterized basic peroxidase so far, but none of these has been directly involved in lignification. We have used a knock-out mutant of AtPrx4, the closest homologue to ZePrx, to study the involvement of this basic peroxidase in the physiology of the plant under both long- and short-day light conditions. Our results suggest that AtPrx4 is involved in cell wall lignification, especially in syringyl monomer formation. The disruption of AtPrx4 causes a decrease in syringyl units proportion, but only when light conditions are optimal. Moreover, the effect of AtPrx4 disruption is age-dependent, and it is only significant when the elongation process of the stem has ceased and lignification becomes active. In conclusion, AtPrx4 emerges as a basic peroxidase regulated by day length with an important role in lignification. PMID:25506770

  10. Lignin valorization through integrated biological funneling and chemical catalysis.

    PubMed

    Linger, Jeffrey G; Vardon, Derek R; Guarnieri, Michael T; Karp, Eric M; Hunsinger, Glendon B; Franden, Mary Ann; Johnson, Christopher W; Chupka, Gina; Strathmann, Timothy J; Pienkos, Philip T; Beckham, Gregg T

    2014-08-19

    Lignin is an energy-dense, heterogeneous polymer comprised of phenylpropanoid monomers used by plants for structure, water transport, and defense, and it is the second most abundant biopolymer on Earth after cellulose. In production of fuels and chemicals from biomass, lignin is typically underused as a feedstock and burned for process heat because its inherent heterogeneity and recalcitrance make it difficult to selectively valorize. In nature, however, some organisms have evolved metabolic pathways that enable the utilization of lignin-derived aromatic molecules as carbon sources. Aromatic catabolism typically occurs via upper pathways that act as a "biological funnel" to convert heterogeneous substrates to central intermediates, such as protocatechuate or catechol. These intermediates undergo ring cleavage and are further converted via the β-ketoadipate pathway to central carbon metabolism. Here, we use a natural aromatic-catabolizing organism, Pseudomonas putida KT2440, to demonstrate that these aromatic metabolic pathways can be used to convert both aromatic model compounds and heterogeneous, lignin-enriched streams derived from pilot-scale biomass pretreatment into medium chain-length polyhydroxyalkanoates (mcl-PHAs). mcl-PHAs were then isolated from the cells and demonstrated to be similar in physicochemical properties to conventional carbohydrate-derived mcl-PHAs, which have applications as bioplastics. In a further demonstration of their utility, mcl-PHAs were catalytically converted to both chemical precursors and fuel-range hydrocarbons. Overall, this work demonstrates that the use of aromatic catabolic pathways enables an approach to valorize lignin by overcoming its inherent heterogeneity to produce fuels, chemicals, and materials. PMID:25092344

  11. Lignin valorization through integrated biological funneling and chemical catalysis

    PubMed Central

    Linger, Jeffrey G.; Vardon, Derek R.; Guarnieri, Michael T.; Karp, Eric M.; Hunsinger, Glendon B.; Franden, Mary Ann; Johnson, Christopher W.; Chupka, Gina; Strathmann, Timothy J.; Pienkos, Philip T.; Beckham, Gregg T.

    2014-01-01

    Lignin is an energy-dense, heterogeneous polymer comprised of phenylpropanoid monomers used by plants for structure, water transport, and defense, and it is the second most abundant biopolymer on Earth after cellulose. In production of fuels and chemicals from biomass, lignin is typically underused as a feedstock and burned for process heat because its inherent heterogeneity and recalcitrance make it difficult to selectively valorize. In nature, however, some organisms have evolved metabolic pathways that enable the utilization of lignin-derived aromatic molecules as carbon sources. Aromatic catabolism typically occurs via upper pathways that act as a “biological funnel” to convert heterogeneous substrates to central intermediates, such as protocatechuate or catechol. These intermediates undergo ring cleavage and are further converted via the β-ketoadipate pathway to central carbon metabolism. Here, we use a natural aromatic-catabolizing organism, Pseudomonas putida KT2440, to demonstrate that these aromatic metabolic pathways can be used to convert both aromatic model compounds and heterogeneous, lignin-enriched streams derived from pilot-scale biomass pretreatment into medium chain-length polyhydroxyalkanoates (mcl-PHAs). mcl-PHAs were then isolated from the cells and demonstrated to be similar in physicochemical properties to conventional carbohydrate-derived mcl-PHAs, which have applications as bioplastics. In a further demonstration of their utility, mcl-PHAs were catalytically converted to both chemical precursors and fuel-range hydrocarbons. Overall, this work demonstrates that the use of aromatic catabolic pathways enables an approach to valorize lignin by overcoming its inherent heterogeneity to produce fuels, chemicals, and materials. PMID:25092344

  12. Synthesis and characterization of new 5-linked pinoresinol lignin models.

    PubMed

    Yue, Fengxia; Lu, Fachuang; Sun, Runcang; Ralph, John

    2012-12-14

    Pinoresinol structures, featuring a β-β'-linkage between lignin monomer units, are important in softwood lignins and in dicots and monocots, particularly those that are downregulated in syringyl-specific genes. Although readily detected by NMR spectroscopy, pinoresinol structures largely escaped detection by β-ether-cleaving degradation analyses presumably due to the presence of the linkages at the 5 positions, in 5-5'- or 5-O-4'-structures. In this study, which is aimed at helping better understand 5-linked pinoresinol structures by providing the required data for NMR characterization, new lignin model compounds were synthesized through biomimetic peroxidase-mediated oxidative coupling reactions between pre-formed (free-phenolic) coniferyl alcohol 5-5'- or 5-O-4'-linked dimers and a coniferyl alcohol monomer. It was found that such dimers containing free-phenolic coniferyl alcohol moieties can cross-couple with the coniferyl alcohol producing pinoresinol-containing trimers (and higher oligomers) in addition to other homo- and cross-coupled products. Eight new lignin model compounds were obtained and characterized by NMR spectroscopy, and one tentatively identified cross-coupled β-O-4'-product was formed from a coniferyl alcohol 5-O-4'-linked dimer. It was demonstrated that the 5-5'- and 5-O-4'-linked pinoresinol structures could be readily differentiated by using heteronuclear multiple-bond correlation (HMBC) NMR spectroscopy. With appropriate modification (etherification or acetylation) to the newly obtained model compounds, it would be possible to identify the 5-5'- or 5-O-4'-linked pinoresinol structures in softwood lignins by 2D HMBC NMR spectroscopic methods. Identification of the cross-coupled dibenzodioxocin from a coniferyl alcohol 5-5'-linked moiety suggested that thioacidolysis or derivatization followed by reductive cleavage (DFRC) could be used to detect and identify whether the coniferyl alcohol itself undergoes 5-5'-cross-linking during

  13. Surface energy and wettability of spin-coated thin films of lignin isolated from wood.

    PubMed

    Notley, Shannon M; Norgren, Magnus

    2010-04-20

    The surface energy of lignin films spin-coated onto oxidized silicon wafer has been determined from contact angle measurements of different test liquids with varying polar and dispersive components. Three different lignin raw materials were used, a kraft lignin from softwood, along with milled wood lignin from softwood and hardwood. Infrared and (31)P NMR spectroscopy was used to identify any major functional group differences between the lignin samples. No significant difference in the total solid-vapor surface energy for the different lignin films was observed; however, the polar component for the kraft lignin was much greater than for either of the milled wood lignin samples consistent with the presence of carboxyl groups and higher proportion of phenolic hydroxyl groups as shown by quantitative (31)P NMR on the phosphitylated samples. Furthermore, the total surface energy of lignin of 53-56 mJ m(-2) is of a similar magnitude to cellulose, also found in the wood cell wall; however, cellulose has a higher polar component leading to a lower contact angle with water and greater wettability than the milled wood lignin. Although lignin is not hydrophobic according to the strictest definition of a water contact angle greater than 90 degrees, water may only be considered a partially wetting liquid on a lignin surface. This supports the long-held belief that one of the functions of lignin in the wood cell wall is to provide water-proofing to aid in water transport. Furthermore, these results on the solid-vapor surface energy of lignin will provide invaluable insight for many natural and industrial applications including in the design and manufacture of many sustainable products such as paper, fiberboard, and polymer composite blends. PMID:20349913

  14. Cell wall fermentation kinetics impacted more by lignin content and cross-linking than by diverse shifts in lignin composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We used a biomimetic model system to ascertain how lignification and diverse shifts in lignin cross-linking and composition influence cell wall fermentation. Primary cell walls from nonlignified maize cell suspensions were artificially lignified with varying ratios of normal monolignols (coniferyl a...

  15. Characteristics of Lignin from Flax Shives as Affected by Extraction Conditions

    PubMed Central

    Ross, Kelly; Mazza, Giuseppe

    2010-01-01

    Lignin, a polyphenolic molecule, is a major constituent of flax shives. This polyphenolic molecular structure renders lignin a potential source of a variety of commercially viable products such as fine chemicals. This work compares the performance of different lignin isolation methods. Lignin from flax shive was isolated using both conventional alkaline extraction method and a novel experimental pressurized low polarity water (PLPW) extraction process. The lignin yields and chemical composition of the lignin fractions were determined. The conventional alkali treatment with 1.25 M NaOH, heated at 80 °C for 5 h, extracted 92 g lignin per kg flax shives, while lignin yields from the PLPW extracts ranged from 27 to 241 g lignin per kg flax shives. The purity and monomeric composition of the lignins obtained from the different extraction conditions was assessed via UV spectroscopy and alkaline nitrobenzene oxidation. Lignin obtained from conventional alkali treatment with 1.25 M NaOH, heated at 80 °C for 5 h was of low purity and exhibited the lowest yields of nitrobenzene oxidation products. With respect to alkali assisted PLPW extractions, temperature created an opposing effect on lignin yield and nitrobenzene oxidation products. More lignin was extracted as temperature increased, yet the yield of nitrobenzene oxidation products decreased. The low yield of nitrobenzene oxidation products may be attributed to either the formation of condensed structures or the selective dissolution of condensed structures of lignin during the pressurized alkaline high temperature treatment. Analytical pyrolysis, using pyroprobe GC-MS, was used to investigate the molecular composition of the lignin samples. The total yield of pyrolysis lignin products was 13.3, 64.7, and 30.5% for the 1.25 M NaOH extracted lignin, alkaline assisted PLPW extracted lignin, and the unprocessed flax shives, respectively. Key lignin derived compounds such as guaiacol, 4-vinyl guaiacol, 4-methyl guaiacol

  16. Fate and transport of lignin in the soil-water continuum

    NASA Astrophysics Data System (ADS)

    Williams, J. S.; Dungait, J.; Bol, R.; Abbott, G. D.

    2011-12-01

    Soils have been identified as having the potential to store greater amounts of carbon (C) in soil organic matter (SOM) through appropriate land uses and management practices to increase the input of recalcitrant components of organic matter, such as lignin. Lignin is allocated to the 'slow' soil C pools with residence times between 15 - 100 yrs. Lignin is 30% of the C fixed by plants and is an important C input to soils. However, Recent research has shown that the configuration of lignin monomers within the lignin macromolecule is not random [1], that lignin degradation is monomer specific [2], and that lignin is preferentially degraded relative to the bulk SOM [3], thereby questioning the role of lignin in C sequestration. Although guaiacyl (G) and syringyl (S) lignin monomers have been identified in fresh, estuarine, and marine waters [4], the initial forms to which lignin is degraded into water-transportable products and lost from the soil C reservoir are not known. The aims of this project are to (i) identify and quantify the lignin-derived products entering the soluble phase in soils, and (ii) determine the rate of lignin degradation into water-soluble components, and their rate of transport through soil. In experiment 1 we tested the best approach to extract and analyse dissolved lignin from outflows from grassland and woodland sites. C18 solid phase extraction (SPE) or freeze-drying (FD) was used to isolate water-borne lignin monomers. Gas chromatography-mass spectrometry (GC-MS) of trimethylsilyl (TMS) derivatives or tetramethylammonium hydroxide (TMAH) thermochemolysis was used to analyse the samples. In a subsequent experiment, we allowed leaves from different vegetation types (Lolium perenne, Ranunculus repens, Fraxinus excelsior, Quercus robur), corresponding to the vegetation at our initial sites in Experiment 1, to degrade in soil lysimeters for 1.5 years to determine the rates of decomposition of different plant material and dominant form of lignin

  17. Comparison of XAD with other dissolved lignin isolation techniques and a compilation of analytical improvements for the analysis of lignin in aquatic settings

    USGS Publications Warehouse

    Spencer, R.G.M.; Aiken, G.R.; Dyda, R.Y.; Butler, K.D.; Bergamaschi, B.A.; Hernes, P.J.

    2010-01-01

    This manuscript highlights numerous incremental improvements in dissolved lignin measurements over the nearly three decades since CuO oxidation of lignin phenols was first adapted for environmental samples. Intercomparison of the recovery efficiency of three common lignin phenol concentration and isolation techniques, namely XAD, C18 with both CH3OH (C18M) and CH3CN (C18A) used independently for priming and elution steps, and tangential flow filtration (TFF) for a range of aquatic samples including fresh, estuarine and marine waters, was undertaken. With freshwater samples XAD8-1, C18M and TFF were all observed to recover ca. 80-90% of the lignin phenols and showed no fractionation effects with respect to diagnostic lignin parameters. With estuarine and marine samples more lignin phenols were recovered with C18M and XAD8-1 than TFF because of the increased prevalence of low molecular weight lignin phenols in marine influenced samples. For marine systems, differences were also observed between diagnostic lignin parameters isolated via TFF vs. C18M and XAD8-1 as a result of the high molecular weight lignin phenols being less degraded than the bulk. Therefore, it is recommended for future studies of marine systems that only one technique is utilized for ease of intercomparison within studies. It is suggested that for studies solely aimed at recovering bulk dissolved lignin in marine environments that C18M and XAD8-1 appear to be more suitable than TFF as they recover more lignin. Our results highlight that, for freshwater samples, all three common lignin phenol concentration and isolation techniques are comparable to whole water concentrated by rotary evaporation (i.e. not isolated) but, that for marine systems, the choice of concentration and isolation techniques needs to be taken into consideration with respect to both lignin concentration and diagnostic parameters. Finally, as the study highlights XAD8-1 to be a suitable method for the isolation of dissolved lignin

  18. Production of monodisperse, polymeric microspheres

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Rhim, Won-Kyu (Inventor); Hyson, Michael T. (Inventor); Chang, Manchium (Inventor)

    1990-01-01

    Very small, individual polymeric microspheres with very precise size and a wide variation in monomer type and properties are produced by deploying a precisely formed liquid monomer droplet, suitably an acrylic compound such as hydroxyethyl methacrylate into a containerless environment. The droplet which assumes a spheroid shape is subjected to polymerizing radiation such as ultraviolet or gamma radiation as it travels through the environment. Polymeric microspheres having precise diameters varying no more than plus or minus 5 percent from an average size are recovered. Many types of fillers including magnetic fillers may be dispersed in the liquid droplet.

  19. Melting line of polymeric nitrogen

    NASA Astrophysics Data System (ADS)

    Yakub, L. N.

    2013-05-01

    We made an attempt to predict location of the melting line of polymeric nitrogen using two equations for Helmholtz free energy: proposed earlier for cubic gauche-structure and developed recently for liquid polymerized nitrogen. The P-T relation, orthobaric densities and latent heat of melting were determined using a standard double tangent construction. The estimated melting temperature decreases with increasing pressure, alike the temperature of molecular-nonmolecular transition in solid. We discuss the possibility of a triple point (solid-molecular fluid-polymeric fluid) at ˜80 GPa and observed maximum of melting temperature of nitrogen.

  20. High temperature structural, polymeric foams from high internal emulsion polymerization

    SciTech Connect

    Hoisington, M.A.; Duke, J.R.; Apen, P.G.

    1996-02-01

    In 1982, a high internal phase emulsion (HIPE) polymerization process to manufacture microcellular, polymeric foam systems was patented by Unilever. This patent discloses a polymerization process that occurs in a water-in-oil emulsion in which the water represents at least 76% of the emulsion by volume. The oil phase consists of vinyl monomers such as styrene and acrylates that are crosslinked by divinyl monomers during polymerization. After polymerization and drying to remove the water phase, the result is a crosslinked polymer foam with an open cell microstructure that is homogeneous throughout in terms of morphology, density, and mechanical properties. Since 1982, numerous patents have examined various HIPE polymerized foam processing techniques and applications that include absorbents for body fluids, cleaning materials, and ion exchange systems. All the published HIPE polymerized foams have concentrated on materials for low temperature applications. Copolymerization of styrene with maleic anhydride and N-substituted maleimides to produce heat resistant thermoplastics has been studied extensively. These investigations have shown that styrene will free radically copolymerize with N-substituted maleimides to create an alternating thermoplastic copolymer with a Tg of approximately 200{degrees}C. However, there are many difficulties in attempting the maleimide styrene copolymerization in a HIPE such as lower polymerization temperatures, maleimide solubility difficulties in both styrene and water, and difficulty obtaining a stable HIPE with a styrene/maleimide oil phase. This work describes the preparation of copolymer foams from N-ethylmaleimide and Bis(3-ethyl-5-methyl-4-maleimide-phenyl)methane with styrene based monomers and crosslinking agents.

  1. Organometallic Polymeric Conductors

    NASA Technical Reports Server (NTRS)

    Youngs, Wiley J.

    1997-01-01

    For aerospace applications, the use of polymers can result in tremendous weight savings over metals. Suitable polymeric materials for some applications like EMI shielding, spacecraft grounding, and charge dissipation must combine high electrical conductivity with long-term environmental stability, good processability, and good mechanical properties. Recently, other investigators have reported hybrid films made from an electrically conductive polymer combined with insulating polymers. In all of these instances, the films were prepared by infiltrating an insulating polymer with a precursor for a conductive polymer (either polypyrrole or polythiophene), and oxidatively polymerizing the precursor in situ. The resulting composite films have good electrical conductivity, while overcoming the brittleness inherent in most conductive polymers. Many aerospace applications require a combination of properties. Thus, hybrid films made from polyimides or other engineering resins are of primary interest, but only if conductivities on the same order as those obtained with a polystyrene base could be obtained. Hence, a series of experiments was performed to optimize the conductivity of polyimide-based composite films. The polyimide base chosen for this study was Kapton. 3-MethylThiophene (3MT) was used for the conductive phase. Three processing variables were identified for producing these composite films, namely time, temperature, and oxidant concentration for the in situ oxidation. Statistically designed experiments were used to examine the effects of these variables and synergistic/interactive effects among variables on the electrical conductivity and mechanical strength of the films. Multiple linear regression analysis of the tensile data revealed that temperature and time have the greatest effect on maximum stress. The response surface of maximum stress vs. temperature and time (for oxidant concentration at 1.2 M) is shown. Conductivity of the composite films was measured for

  2. Independent Recruitment of an O-Methyltransferase for Syringyl Lignin Biosynthesis in Selaginella moellendorffii[W

    PubMed Central

    Weng, Jing-Ke; Akiyama, Takuya; Ralph, John; Chapple, Clint

    2011-01-01

    Syringyl lignin, an important component of the secondary cell wall, has traditionally been considered to be a hallmark of angiosperms because ferns and gymnosperms in general lack lignin of this type. Interestingly, syringyl lignin was also detected in Selaginella, a genus that represents an extant lineage of the most basal of the vascular plants, the lycophytes. In angiosperms, syringyl lignin biosynthesis requires the activity of ferulate 5-hydroxylase (F5H), a cytochrome P450-dependent monooxygenase, and caffeic acid/5-hydroxyferulic acid O-methyltransferase (COMT). Together, these two enzymes divert metabolic flux from the biosynthesis of guaiacyl lignin, a lignin type common to all vascular plants, toward syringyl lignin. Selaginella has independently evolved an alternative lignin biosynthetic pathway in which syringyl subunits are directly derived from the precursors of p-hydroxyphenyl lignin, through the action of a dual specificity phenylpropanoid meta-hydroxylase, Sm F5H. Here, we report the characterization of an O-methyltransferase from Selaginella moellendorffii, COMT, the coding sequence of which is clustered together with F5H at the adjacent genomic locus. COMT is a bifunctional phenylpropanoid O-methyltransferase that can methylate phenylpropanoid meta-hydroxyls at both the 3- and 5-position and function in concert with F5H in syringyl lignin biosynthesis in S. moellendorffii. Phylogenetic analysis reveals that Sm COMT, like F5H, evolved independently from its angiosperm counterparts. PMID:21742988

  3. Lignin binding to pancreatic lipase and its influence on enzymatic activity.

    PubMed

    Zhang, Juan; Xiao, Lin; Yang, Yucai; Wang, Zhaoxia; Li, Genxi

    2014-04-15

    In this paper, we find that the effect of lignin on pancreatic lipase (PL) is dependent on reaction medium and substrate used. Experimental results reveal that lignin can gradually bind to PL to form a PL-lignin complex, resulting in an increased activity of the enzyme. The binding process is spontaneous and the PL-lignin complex formation is an endothermic reaction induced by hydrophobic and electrostatic interaction. There is a non-radiation energy transfer from PL to lignin during the binding process, and the binding of lignin to PL conforms to a secondary exponential decay function. Moreover, the α-helix content of the enzyme will be changed and the rigidity of its side chain will be enhanced due to the formation of lignin-PL complex. This study has not only provided the activation effect of lignin on PL, but also given an insight into the interaction between lignin and the enzyme, which would benefit the application of lignin in the pharmacy and food industry, as well as other fields. PMID:24295682

  4. Characterization and determination of lignin in different types of Iraqi phoenix date palm pruning woods.

    PubMed

    Abdullah, Hilal M; Abdul Latif, Mohammed H; Attiya, Hanaa G

    2013-10-01

    This study aimed to find analytical data base for Iraqi phoenix date palm pruning woods, which produced by pruning process at the season of date palm production. Lignin has been extracted and purified for five types of Iraqi date palm using Klason lignin method. The weight of the extracted lignin ranged from 0.410 g to 0.720 g, and the lignin % ranged from 17.6 to 36. The other ingredients (waxes, oils, resin, and proteins of wood gums) % ranged from 20 to 29.5. FT-IR characterization showed that the (-OH) phenolic group appear in Ashrasi lignin structure only and disappear in other lignin samples, and the (4-O-5 inter monomeric lignin linkage) showed strong to moderate intensity peaks for all studied samples except the Austa omran sample has a weak intensity peaks. Also (DODO inter monomeric lignin linkage) showed strong intensity peaks for all studied samples except the Barban sample showed moderate intensity peaks. UV-vis characterization showed that the lowest absorption maximum (266 nm) corresponds to Barban lignin sample, while the highest absorption maximum (271 nm) corresponds to Sultani lignin sample. PMID:23811162

  5. Genoprotective effects of lignin isolated from oil palm black liquor waste.

    PubMed

    Naik, Prashantha; Rozman, Hj Din; Bhat, Rajeev

    2013-07-01

    Black liquor waste (BLW), a major by-product of palm oil extraction process contains lignin as one of the constituents. Lignin isolated from BLW was evaluated for antioxidant and genoprotective properties and was compared with the commercial lignin for overall efficacy. Antioxidant compounds (phenolics and tannins) and antioxidant activities (phosphomolybdenum assay, ABTS(+) and FRAP assays) of lignin isolated from BLW were compared with commercial lignin. Bone marrow micronucleus (MN) test was employed for evaluating the dose-yield protective effect against cyclophosphamide (CP, 50mg/kg b.w.) induced genotoxicity in mouse. Results revealed isolated lignin to exhibit rich antioxidant activities. A decrease in MN frequency and recovery of P/N ratio (P: polychromatic erythrocytes, N: normochromatic erhythocytes) indicated protective effects of lignin against cyclophosphamide induced genotoxicity and cytotoxicity. The efficacy of BLW-derived lignin as an antioxidant and genoprotective agent was comparable to commercial lignin. Results on lignin isolated from BLW are envisaged to find potential applications in food and/or pharmaceutical industries. PMID:23603466

  6. An ab initio molecular dynamics analysis of lignin as a potential antioxidant for hydrocarbons.

    PubMed

    Pan, Tongyan; Cheng, Cheng

    2015-11-01

    Lignins are complex phenolic polymers with limited industrial uses. To identify new applications of lignins, this study aims to evaluate the conifer alcohol lignin as a potential antioxidant for hydrocarbons, using the petroleum asphalt as an example. Using the ab initio molecular dynamics (AIMD) method, the evaluation is accomplished by tracking the generation of critical species in a lignin-asphalt mixture under a simulated oxidative condition. The generation of new species was detected using nuclear magnetic resonance and four analytical methods including density of states analysis, highest occupied molecular orbital and lowest unoccupied molecular orbital analyses, bonding and energy level analysis, and electrostatic potential energy analysis. Results of the analyses show that the chemical radicals of carbon, nitrogen and sulfur generated in the oxidation process could enhance the agglomeration and/or decomposition tendency of asphalt. The effectiveness of lignins as an antioxidant depends on their chemical compositions. Lignins with a HOMO-LUMO gap larger than the HOMO-LUMO gap of the hydrocarbon system to be protected, such as the conifer alcohol lignin to protect petroleum asphalt as was studied in this work, do not demonstrate beneficial anti-oxidation capacity. Lignins, however, may be effective oxidants for hydrocarbon systems with a larger HOMO-LUMO gap. In addition, lignins may contain more polar sites than the hydrocarbons to be protected; thus the lignins' hydrophobicity and compatibility with the host hydrocarbons need to be well evaluated. The developed AIMD model provides a useful tool for developing antioxidants for generic hydrocarbons. PMID:26562413

  7. Peracetic Acid Depolymerization of Biorefinery Lignin for Production of Selective Monomeric Phenolic Compounds.

    PubMed

    Ma, Ruoshui; Guo, Mond; Lin, Kuan-Ting; Hebert, Vincent R; Zhang, Jinwen; Wolcott, Michael P; Quintero, Melissa; Ramasamy, Karthikeyan K; Chen, Xiaowen; Zhang, Xiao

    2016-07-25

    Lignin is the largest source of renewable material with an aromatic skeleton. However, due to the recalcitrant and heterogeneous nature of the lignin polymer, it has been a challenge to effectively depolymerize lignin and produce high-value chemicals with high selectivity. In this study, a highly efficient lignin-to-monomeric phenolic compounds (MPC) conversion method based on peracetic acid (PAA) treatment was reported. PAA treatment of two biorefinery lignin samples, diluted acid pretreated corn stover lignin (DACSL) and steam exploded spruce lignin (SESPL), led to complete solubilization and production of selective hydroxylated monomeric phenolic compounds (MPC-H) and monomeric phenolic acid compounds (MPC-A) including 4-hydroxy-2-methoxyphenol, p-hydroxybenzoic acid, vanillic acid, syringic acid, and 3,4-dihydroxybenzoic acid. The maximized MPC yields obtained were 18 and 22 % based on the initial weight of the lignin in SESPL and DACSL, respectively. However, we found that the addition of niobium pentoxide catalyst to PAA treatment of lignin can significantly improve the MPC yields up to 47 %. The key reaction steps and main mechanisms involved in this new lignin-to-MPC valorization pathway were investigated and elucidated. PMID:27373451

  8. Turning Renewable Resources into Recyclable Polymer: Development of Lignin-Based Thermoplastic

    SciTech Connect

    Saito, Tomonori; Brown, Rebecca H; Hunt, Marcus A; Pickel, Deanna L; Pickel, Joseph M; Messman, Jamie M; Baker, Frederick S; Keller, Martin; Naskar, Amit K

    2012-01-01

    Productive uses of lignin, the third most abundant natural polymer, have been sought for decades. One especially attractive possibility is that of developing value-added products including thermoplastics based on lignin. This possibility warrants special attention due to growth of the modern biofuel industries. However, the polydisperse molecular weight and hyper-branched structure of lignin has hindered the creation of high-performance biopolymers. Here, we report the preparation and characterization of novel lignin-based, partially carbon-neutral thermoplastics. We first altered the molecular weight of lignin, either by fractionation with methanol, or by formaldehyde crosslinking. A crosslinking of lignin increases the molecular weight, exhibiting Mn = 31000 g/mol, whereas that of native lignin is 1840 g/mol. Tuning the molecular weight of lignin enabled successful preparation of novel lignin-derived thermoplastics, when coupled with telechelic polybutadiene soft-segments at proper feed ratios. Characteristic to thermoplastic rubbers, free-standing films of the resulting copolymers exhibit two-phase morphology and associated relaxations in the dynamic mechanical loss spectrum. To our knowledge this article is the first report to demonstrate phase immiscibility, melt-processibility, and biphasic morphology of soft and hard segments in a lignin-based copolymer for all feed ratios of two macromolecular components. The use of higher molecular weight lignin enhanced the resulting shear modulus due to efficient network formation of telechelic polybutadiene bridges. The storage modulus in the rubbery plateau region increased with increasing lignin content. The successful synthesis of novel lignin-based thermoplastics will open a new pathway to biomass utilization and will help conserve petrochemicals.

  9. Probing organic matter transfer dynamics in river systems using lignin phenol 14C ages

    NASA Astrophysics Data System (ADS)

    Feng, X.; Vonk, J. E.; Gustafsson, O.; Galy, V.; Holmes, R. M.; Mann, P. J.; Montlucon, D.; Eglinton, T. I.

    2011-12-01

    As an important and ubiquitous component of terrestrial organic matter, lignin is widely dispersed by rivers during the land-ocean transfer. While the distribution and composition of lignin-derived phenols have been extensively investigated, little is known on their radiocarbon age, which carries information on the residence time and/or source of organic matter during fluvial transport. Recently, we have developed a high pressure liquid chromatography-based method of isolating individual lignin phenols for radiocarbon analysis. We employed compound-specific radiocarbon analysis to investigate the provenance and transport of lignin in sedimentary particles from several major river systems that span a range of latitudes spanning Arctic (Mackenzie, Kolyma, Indigirka, Lena, Yenisey, Ob, and Kalix), temperate (Columbia), to tropical regions (Congo and Ganges-Brahmaputra). The radiocarbon age of lignin phenols ranged from modern in the tropical (Congo and Ganges-Brahmaputra) rivers to approximately 4000 years in the Arctic (Kolyma and Indigirka). The latter, while clearly reflecting protracted storage of lignin within Arctic river drainage basins, is much younger than plant wax lipids isolated from the same sediments. This observation indicates that lignin is a relatively rapidly cycling component of the terrestrial organic matter transported by rivers. The general correlation between the radiocarbon age of lignin phenols and the latitude of rivers suggests climatic control over the preservation and storage of lignin within the river drainage basins. Individual lignin phenols were also isolated from the dissolved organic matter from several of these major rivers (including Congo, Fraser, Ganges-Brahmaputra, Mackenzie, and Yangtze, etc.) and compared their composition and radiocarbon age with those in the suspended particles collected from the same river system. Such comparison allows the assessment of lignin fractionation and degradation in the dissolved and particulate

  10. Lignin decomposition along an Alpine elevation gradient in relation to physicochemical and soil microbial parameters.

    PubMed

    Duboc, Olivier; Dignac, Marie-France; Djukic, Ika; Zehetner, Franz; Gerzabek, Martin H; Rumpel, Cornelia

    2014-07-01

    Lignin is an aromatic plant compound that decomposes more slowly than other organic matter compounds; however, it was recently shown that lignin could decompose as fast as litter bulk carbon in minerals soils. In alpine Histosols, where organic matter dynamics is largely unaffected by mineral constituents, lignin may be an important part of soil organic matter (SOM). These soils are expected to experience alterations in temperature and/or physicochemical parameters as a result of global climate change. The effect of these changes on lignin dynamics remains to be examined and the importance of lignin as SOM compound in these soils evaluated. Here, we investigated the decomposition of individual lignin phenols of maize litter incubated for 2 years in-situ in Histosols on an Alpine elevation gradient (900, 1300, and 1900 m above sea level); to this end, we used the cupric oxide oxidation method and determined the phenols' (13) C signature. Maize lignin decomposed faster than bulk maize carbon in the first year (86 vs. 78% decomposed); however, after the second year, lignin and bulk C decomposition did not differ significantly. Lignin mass loss did not correlate with soil temperature after the first year, and even correlated negatively at the end of the second year. Lignin mass loss also correlated negatively with the remaining maize N at the end of the second year, and we interpreted this result as a possible negative influence of nitrogen on lignin degradation, although other factors (notably the depletion of easily degradable carbon sources) may also have played a role at this stage of decomposition. Microbial community composition did not correlate with lignin mass loss, but it did so with the lignin degradation indicators (Ac/Al)s and S/V after 2 years of decomposition. Progressing substrate decomposition toward the final stages thus appears to be linked with microbial community differentiation. PMID:24323640

  11. Effect of hypergravity on lignin formation and expression of lignin-related genes in inflorescence stems of an ethylene-insensitive Arabidopsis mutant ein3-1

    NASA Astrophysics Data System (ADS)

    Karahara, Ichirou; Kobayashi, Mai; Tamaoki, Daisuke; Kamisaka, Seiichiro

    Our previous studies have shown that hypergravity inhibits growth and promotes lignin forma-tion in inflorescence stems of Arabidopsis thaliana by up-regulation of genes involved in lignin biosynthesis (Tamaoki et al. 2006, 2009). In the present study, we have examined whether ethylene is involved in these responses using an ethylene-insensitive Arabidopsis mutant ein3-1. Our results revealed that hypergravity treatment at 300 G for 24 h significantly inhibited growth of inflorescence stems, promoted both deposition of acetyl bromide extractable lignin and gene expression involved in lignin formation in inflorescence stems of wild type plants. Growth inhibition of inflorescence stems was also observed in ein3-1. However, the effects of hypergravity on the promotion of the deposition of acetyl bromide lignin and the expression of genes involved in lignin formation were not observed in ein3-1, indicating that ethylene sig-naling is involved in the up-regulation of the expression of lignin-related genes as well as the promotion of deposition of lignin by hypergravity in Arabidopsis inflorescence stems.

  12. Admicellar polymerization of precipated silica

    SciTech Connect

    Reynolds, J.L.; Grady, B.P.; Harwell, J.H.

    1996-10-01

    The tendency of a surfactant molecule to adsorb at a solid-liquid interface is the basis for an in situ surface modification process, termed admicellar polymerization. The four-step admicellar polymerization process includes: (1) adsorption of surfactant at the solid-liquid interface, (2) adsolubilization of monomer into the surfactant bilayer, (3) polymerization using free-radical initiators and heat, (4) removal of excess surfactant to expose the polymer modified surface. The process is used to apply polymer to precipitated silica to enhance the compatibility of the silica when added to filled rubber. The adsorption isotherms were first determined for particular surfactant/silica combinations to find the surfactant concentration that would sufficiently adsolubilize the monomer, while remaining below the critical micelle concentration. A series of experiments were then devised for the polymerization reactions in which the surfactant and monomer amounts were varied over three levels to establish the optimal combination.

  13. Polymerization of anionic wormlike micelles.

    PubMed

    Zhu, Zhiyuan; González, Yamaira I; Xu, Hangxun; Kaler, Eric W; Liu, Shiyong

    2006-01-31

    Polymerizable anionic wormlike micelles are obtained upon mixing the hydrotropic salt p-toluidine hydrochloride (PTHC) with the reactive anionic surfactant sodium 4-(8-methacryloyloxyoctyl)oxybenzene sulfonate (MOBS). Polymerization captures the cross-sectional radius of the micelles (approximately 2 nm), induces micellar growth, and leads to the formation of a stable single-phase dispersion of wormlike micellar polymers. The unpolymerized and polymerized micelles were characterized using static and dynamic laser light scattering, small-angle neutron scattering, 1H NMR, and stopped-flow light scattering. Stopped-flow light scattering was also used to measure the average lifetime of the unpolymerized wormlike micelles. A comparison of the average lifetime of unpolymerized wormlike micelles with the surfactant monomer propagation rate was used to elucidate the mechanism of polymerization. There is a significant correlation between the ratio of the average lifetime to the monomer propagation rate and the average aggregation number of the polymerized wormlike micelles. PMID:16430253

  14. Kinetics of silica polymerization

    SciTech Connect

    Weres, O.; Yee, A.; Tsao, L.

    1980-05-01

    The polymerization of silicic acid in geothermal brine-like aqueous solutions to produce amorphous silica in colloidal form has been studied experimentally and theoretically. A large amount of high quality experimental data has been generated over the temperature rang 23 to 100{sup 0}C. Wide ranges of dissolved silica concentration, pH, and sodium chloride concentration were covered. The catalytic effects of fluoride and the reaction inhibiting effects of aluminum and boron were studied also. Two basic processes have been separately studied: the formation of new colloidal particles by the homogeneous nucleation process and the deposition of dissolved silica on pre-existing colloidal particles. A rigorous theory of the formation of colloidal particles of amorphous silica by homogeneous nucleation was developed. This theory employs the Lothe-Pound formalism, and is embodied in the computer code SILNUC which quantitatively models the homogeneous nucleation and growth of colloidal silica particles in more than enough detail for practical application. The theory and code were extensively used in planning the experimental work and analyzing the data produced. The code is now complete and running in its final form. It is capable of reproducing most of the experimental results to within experimental error. It is also capable of extrapolation to experimentally inaccessible conditions, i.e., high temperatures, rapidly varying temperature and pH, etc.

  15. Biobased Epoxy Nanocomposites Derived from Lignin-Based Monomers.

    PubMed

    Zhao, Shou; Abu-Omar, Mahdi M

    2015-07-13

    Biobased epoxy nanocomposites were synthesized based on 2-methoxy-4-propylphenol (dihydroeugenol, DHE), a molecule that has been obtained from the lignin component of biomass. To increase the content of hydroxyl groups, DHE was o-demethylated using aqueous HBr to yield propylcatechol (DHEO), which was subsequently glycidylated to epoxy monomer. Optimal conditions in terms of yield and epoxy equivalent weight were found to be 60 °C with equal NaOH/phenolic hydroxyl molar ratio. The structural evolution from DHE to cured epoxy was followed by (1)H NMR and Fourier transform infrared spectroscopy. The nano-montmorillonite modified DHEO epoxy exhibited improved storage modulus and thermal stability as determined from dynamic mechanical analysis and thermogravimetric analysis. This study widens the synthesis routes of biobased epoxy thermosets from lignin-based molecules. PMID:26135389

  16. Adsorption studies of methylene blue dye on tunisian activated lignin

    NASA Astrophysics Data System (ADS)

    Kriaa, A.; Hamdi, N.; Srasra, E.

    2011-02-01

    Activated carbon prepared from natural lignin, providing from a geological deposit, was used as the adsorbent for the removal of methylene blue (MB) dye from aqueous solutions. Batch adsorption studies were conducted to evaluate various experimental parameters like pH and contact time for the removal of this dye. Effective pH for MB removal was 11. Kinetic study showed that the adsorption of dye was gradual process. Quasi equilibrium reached in 4 h. Pseudo-first-order, pseudo-second-order were used to fit the experimental data. Pseudo-second-order rate equation was able to provide realistic description of adsorption kinetics. The experimental isotherms data were also modelled by the Langmuir and Freundlich equation of adsorption. Equilibrium data fitted well with the Langmuir model with maximum monolayer adsorption capacity of 147 mg/g. Activated lignin was shown to be a promising material for adsorption of MB from aqueous solutions.

  17. Lignin Based Carbon Materials for Energy Storage Applications

    SciTech Connect

    Chatterjee, Sabornie; Saito, Tomonori; Rios, Orlando; Johs, Alexander

    2014-01-01

    The implementation of Li-ion battery technology into electric and hybrid electric vehicles and portable electronic devices such as smart phones, laptops and tablets, creates a demand for efficient, economic and sustainable materials for energy storage. However, the high cost and long processing time associated with manufacturing battery-grade anode and cathode materials are two big constraints for lowering the total cost of batteries and environmentally friendly electric vehicles. Lignin, a byproduct of the pulp and paper industry and biorefinery, is one of the most abundant and inexpensive natural biopolymers. It can be efficiently converted to low cost carbon fibers with optimal properties for use as anode materials. Recent developments in the preparation of lignin precursors and conversion to carbon fiber-based anode materials have created a new class of anode materials with excellent electrochemical characteristics suitable for immediate use in existing Li- or Na-ion battery technologies.

  18. Performance of biofuel processes utilising separate lignin and carbohydrate processing.

    PubMed

    Melin, Kristian; Kohl, Thomas; Koskinen, Jukka; Hurme, Markku

    2015-09-01

    Novel biofuel pathways with increased product yields are evaluated against conventional lignocellulosic biofuel production processes: methanol or methane production via gasification and ethanol production via steam-explosion pre-treatment. The novel processes studied are ethanol production combined with methanol production by gasification, hydrocarbon fuel production with additional hydrogen produced from lignin residue gasification, methanol or methane synthesis using synthesis gas from lignin residue gasification and additional hydrogen obtained by aqueous phase reforming in synthesis gas production. The material and energy balances of the processes were calculated by Aspen flow sheet models and add on excel calculations applicable at the conceptual design stage to evaluate the pre-feasibility of the alternatives. The processes were compared using the following criteria: energy efficiency from biomass to products, primary energy efficiency, GHG reduction potential and economy (expressed as net present value: NPV). Several novel biorefinery concepts gave higher energy yields, GHG reduction potential and NPV. PMID:26056782

  19. Countercurrent Process for Lignin Separation from Biomass Matrix

    SciTech Connect

    Kiran Kadam; Ed Lehrburger

    2006-03-31

    The overall goal of the project was to test the concept of using a twin-screw extruder to conduct autohydrolysis pretreatment of wheat straw in countercurrent fashion, demonstrate in situ solid/liquid separation, and produce a low-lignin cellulose product using ethanol as an extractant. The resultant solid product is suitable for sugar production through enzymatic hydrolysis and for pulp applications. Pilot-scale equipment was used to successfully demonstrate the process both for sugar and pulp applications.

  20. Comparative analysis of lignin peroxidase and manganese peroxidase activity on coniferous and deciduous wood using ToF-SIMS.

    PubMed

    MacDonald, Jacqueline; Goacher, Robyn E; Abou-Zaid, Mamdouh; Master, Emma R

    2016-09-01

    White-rot fungi are distinguished by their ability to efficiently degrade lignin via lignin-modifying type II peroxidases, including manganese peroxidase (MnP) and lignin peroxidase (LiP). In the present study, time-of flight secondary ion mass spectrometry (ToF-SIMS) was used to evaluate lignin modification in three coniferous and three deciduous wood preparations following treatment with commercial preparations of LiP and MnP from two different white-rot fungi. Percent modification of lignin was calculated as a loss of intact methoxylated lignin over nonfunctionalized aromatic rings, which is consistent with oxidative cleavage of methoxy moieties within the lignin structure. Exposure to MnP resulted in greater modification of lignin in coniferous compared to deciduous wood (28 vs. 18 % modification of lignin); and greater modification of G-lignin compared to S-lignin within the deciduous wood samples (21 vs. 12 %). In contrast, exposure to LiP resulted in similar percent modification of lignin in all wood samples (21 vs 22 %), and of G- and S-lignin within the deciduous wood (22 vs. 23 %). These findings suggest that the selected MnP and LiP may particularly benefit delignification of coniferous and deciduous wood, respectively. Moreover, the current analysis further demonstrates the utility of ToF-SIMS for characterizing enzymatic modification of lignin in wood fibre along with potential advantages over UV and HPCL-MS detection of solubilized delignification products. PMID:27138198

  1. Purification, structural characterization, and modification of organosolv wheat straw lignin.

    PubMed

    Mbotchak, Laurie; Le Morvan, Clara; Duong, Khanh Linh; Rousseau, Brigitte; Tessier, Martine; Fradet, Alain

    2015-06-01

    Biolignin, a wheat straw lignin produced by acetic acid/formic acid/water hydrolysis, was characterized by (31)P and (13)C-(1)H 2D NMR spectroscopy and by size-exclusion chromatography. Biolignin is a mixture of low molar mass compounds (Mn = 1660 g/mol) made up of S, G, and H units and of coumaric and ferulic acid units. β-5 and β-O-4 interunit linkages are partially acylated in the γ-position by acetate and p-coumarate groups. Deacylated samples with a low content of contaminants were obtained by combining alkaline hydrolysis and solvent extraction. The high phenolic OH content found by (31)P NMR reflects the presence of condensed aromatic units, such as 5-5 units. Reaction of purified lignin with ethanol and ethane-1,2-diol yielded esterified lignins much more soluble than Biolignin in common organic solvents. During this reaction, the secondary OH of β-O-4 linkages was simultaneously etherified. Phenol hydroxyethylation by 2-chloroethanol yielded samples containing only aliphatic hydroxyl groups. PMID:25961961

  2. Mechanistic Study of the Acid Degradation of Lignin Model Compounds

    SciTech Connect

    Sturgeon, M.; Kim, S.; Chmely, S. C.; Foust, T. D.; Beckham, G. T.

    2012-01-01

    Lignin is a major constituent of biomass, which remains underutilized in selective biomass conversion strategies to renewable fuels and chemicals. Here we are interested in understanding the mechanisms related to the acid deconstruction of lignin with a combined theoretical and experimental approach. Two model dimers with a b-O-4 aryl ether linkage (2-phenoxy-1-phenethanol and 2-phenoxy-1-phenyl-1,3 propanediol) and model dimmers with an a-O-4 aryl ether linkage were synthesized and deconstructed in H2SO4. The major products of the acidolysis of the b-O-4 compounds consisted of phenol and two aldehydes, phenylacetaldehyde and benzaldehyde. Quantum mechanical calculations were employed to elucidate possible deconstruction mechanisms with transition state theory. To confirm proposed mechanisms several possible intermediates were studied under similar acidolysis conditions. Although the resonance time for cleavage was on the order several hours, we have shown that the cleavage of the aryl ether linkage affords phenol and aldehydes. We would next like to utilize our mechanism of aryl ether cleavage in actual lignin.

  3. LOW COST PRODUCTION OF CARBON FIBERS FROM LIGNIN MATERIALS

    SciTech Connect

    Gallego, Nidia C; Baker, Darren A; Baker, Frederick S

    2009-01-01

    The DOE Vehicle Technologies-funded work at ORNL is directed to the development of processes for the low cost production of carbon fibers. The objective of the project is to develop more energy-efficient, cost-effective processes for production of carbon fibers for use in composite materials for vehicles, which would substantially reduce vehicle weight, increase vehicle fuel economy, and result in lower CO2 emissions. Carbon fibers have the potential for substantial weight saving in vehicles because of their remarkable high strength, high modulus, and low density. However, carbon fibers are currently too expensive for large scale automotive use, which necessitates a large reduction in the cost of commercial grade fiber from about $20/lb to $5-7/lb. Lignin, a renewable resource material, has significant potential as a precursor material for low cost carbon fiber production. In this paper we report on progress to demonstrate the melt-spinning of precursor fibers from various lignin sources, the subsequent processing of the lignin precursor fibers into carbon fibers, and carbon fiber properties.

  4. Phenolic compounds in ectomycorrhizal interaction of lignin modified silver birch

    PubMed Central

    Sutela, Suvi; Niemi, Karoliina; Edesi, Jaanika; Laakso, Tapio; Saranpää, Pekka; Vuosku, Jaana; Mäkelä, Riina; Tiimonen, Heidi; Chiang, Vincent L; Koskimäki, Janne; Suorsa, Marja; Julkunen-Tiitto, Riitta; Häggman, Hely

    2009-01-01

    Background The monolignol biosynthetic pathway interconnects with the biosynthesis of other secondary phenolic metabolites, such as cinnamic acid derivatives, flavonoids and condensed tannins. The objective of this study is to evaluate whether genetic modification of the monolignol pathway in silver birch (Betula pendula Roth.) would alter the metabolism of these phenolic compounds and how such alterations, if exist, would affect the ectomycorrhizal symbiosis. Results Silver birch lines expressing quaking aspen (Populus tremuloides L.) caffeate/5-hydroxyferulate O-methyltransferase (PtCOMT) under the 35S cauliflower mosaic virus (CaMV) promoter showed a reduction in the relative expression of a putative silver birch COMT (BpCOMT) gene and, consequently, a decrease in the lignin syringyl/guaiacyl composition ratio. Alterations were also detected in concentrations of certain phenolic compounds. All PtCOMT silver birch lines produced normal ectomycorrhizas with the ectomycorrhizal fungus Paxillus involutus (Batsch: Fr.), and the formation of symbiosis enhanced the growth of the transgenic plants. Conclusion The down-regulation of BpCOMT in the 35S-PtCOMT lines caused a reduction in the syringyl/guaiacyl ratio of lignin, but no significant effect was seen in the composition or quantity of phenolic compounds that would have been caused by the expression of PtCOMT under the 35S or UbB1 promoter. Moreover, the detected alterations in the composition of lignin and secondary phenolic compounds had no effect on the interaction between silver birch and P. involutus. PMID:19788757

  5. Heterogeneous Ozonolysis of Surface Adsorbed Lignin Pyrolysis Products

    NASA Astrophysics Data System (ADS)

    Hinrichs, R. Z.

    2012-12-01

    Biomass combustion releases semi-volatile organic compounds into the troposphere, including many phenols and methoxyphenols as the result of lignin pyrolysis. Given their relatively low vapor pressures, these compounds readily adsorb on inorganic and organic aerosol substrates where they may alter aerosol properties and undergo heterogeneous chemistry. We use infrared spectroscopy (DRIFTS and ATR-FTIR) to monitor the adsorption and subsequent heterogeneous ozonolysis of model lignin pyrolysis products, including catechol, eugenol, and 4-propylguaiacol. Ozonolysis reaction kinetics were compared on various inorganic substrates - such as Al2O3 and NaCl, which serve as mineral and sea salt aerosol substrates, respectively - and as a function of ozone concentration and relative humidity. Following in situ FTIR analysis, the adsorbed organics were extracted and analyzed using gas chromatography-mass spectroscopy to identify reaction products and quantify product branching ratios. Ozonolysis of catechol and 4-propylguaiacol readily resulted in ring cleavage forming dicarboxylic acids (e.g., muconic acid). Eugenol ozonolysis proceeded rapidly at the alkene side chain producing homovanillic acid and homovanillin in an approximate 2:1 branching ratio at 0% RH; ring cleavage was also observed. For all lignin pyrolysis products, heterogeneous ozonolysis was faster on NaCl versus Al2O3. Implications for the atmospheric chemistry of semi-volatile methoxylphenols adsorbed on aerosol substrates will be discussed.

  6. Development of a prototype lignin concentration sensor. Final report. Draft

    SciTech Connect

    Jeffers, L.A.

    1994-11-01

    The ultimate objective of the DOE-sponsored program discussed in this report is to commercialize an instrument for real-time, in-situ measurement of lignin in wood pulp at a variety of locations in the pulp process stream. The instrument will be used as a primary sensor for process control in the pulp and paper industry. Work done by B&W prior to the initiation of this program had shown: there is a functional relationship between the fluorescence intensity and the Kappa number as measured at the pulp mill laboratory. Kappa number is a standard wet chemical method for determination of the lignin concentration; the relationship is one of decreasing intensity with Kappa number, indicating operation in the quenched fluorescence regime; a great deal of scatter in the data. Because of the preliminary nature of the study, the origin of the scatter was not identified. This report documents the results of laboratory measurements made on a variety of well defined pulp samples to generate the data necessary to: determine the feasibility of an instrument for on-line lignin concentration measurement using laser fluorescence; identify the preferred measurement strategy; define the range of applicability of the instrument; and to provide background information to guide the design of a field-worthy prototype.

  7. High-Strength Composite Fibers from Cellulose-Lignin Blends Regenerated from Ionic Liquid Solution.

    PubMed

    Ma, Yibo; Asaadi, Shirin; Johansson, Leena-Sisko; Ahvenainen, Patrik; Reza, Mehedi; Alekhina, Marina; Rautkari, Lauri; Michud, Anne; Hauru, Lauri; Hummel, Michael; Sixta, Herbert

    2015-12-01

    Composite fibres that contain cellulose and lignin were produced from ionic liquid solutions by dry-jet wet spinning. Eucalyptus dissolving pulp and organosolv/kraft lignin blends in different ratios were dissolved in the ionic liquid 1,5-diazabicyclo[4.3.0]non-5-enium acetate to prepare a spinning dope from which composite fibres were spun successfully. The composite fibres had a high strength with slightly decreasing values for fibres with an increasing share of lignin, which is because of the reduction in crystallinity. The total orientation of composite fibres and SEM images show morphological changes caused by the presence of lignin. The hydrophobic contribution of lignin reduced the vapour adsorption in the fibre. Thermogravimetric analysis curves of the composite fibres reveal the positive effect of the lignin on the carbonisation yield. Finally, the composite fibre was found to be a potential raw material for textile manufacturing and as a precursor for carbon fibre production. PMID:26542190

  8. Mechanism of the catalytic ozonization of lignin in the presence of Mn(II) ions

    NASA Astrophysics Data System (ADS)

    Mitrofanova, A. N.; Khudoshin, A. G.; Lunin, V. V.

    2013-07-01

    The reaction between ozone and lignin in aqueous solutions catalyzed by Mn(II) ions is studied. The rate of destruction for aromatic structures of lignin is found to increase in the presence of Mn(II) ions. However, the greatest catalytic effect is observed upon the transformation of aliphatic acids that are difficult to oxidize with ozone. The introduction of catalyst raises the total consumption of ozone from 3 to 7 mol per each structural unit of lignin. A scheme is proposed for the transformation of phenol fragments of lignin using ozone with the participation of Mn(II) ions: at the initial stage, we observe the ozone oxidation of lignin and Mn(II) to Mn(III) ions stabilized with products of lignin oxidation and accompanied by the formation of chelate complexes, and the Mn(III) chelate complexes act as low-molecular mediators, attacking phenol structures and initiating radical processes.

  9. Purification of empty fruit bunch (EFB) and kenaf soda lignin with acidified water

    NASA Astrophysics Data System (ADS)

    Hashim, Sharifah Nurul Ain Syed; Zakaria, Sarani; Jaafar, Sharifah Nabihah Syed; Hua, Chia Chin

    2014-09-01

    In this current study, the soda lignins from empty fruit bunch (EFB) and kenaf core were recovered by two step precipitation method. The objective of this research is to study the purity of lignin by washing the lignins with acidified water. The purified lignins were undergone characterization by FT-IR, Uv-Vis and XRD. The FT-IR analysis shows that kenaf core has Guaiacyl(G) and Syringyl(S) unit meanwhile EFB has Hydroxyphenyl(H), Guaiacyl(G) and Syringyl(S) unit of lignin. As for XRD analysis, the non-purified shows that the existence of impurities which is salt (NaCl). The UV analysis shows the higher absorbance which lead to the purity of lignin.

  10. Synthesis and Characterization of Transition Metal Complexes Useful for the Catalytic Deconstruction of Lignin

    SciTech Connect

    Chmely, S. C.; Kim, S.; Beckham, G. T.

    2012-01-01

    Lignin is an earth-abundant biopolymer that is grossly underutilized as a source of fuels and value-added chemicals. However, lignin is an intractable heteropolymer, which makes it difficult to deconstruct and upgrade in many chemically selective biomass conversion routes. The development of new catalytic routes to depolymerize this recalcitrant biopolymer is required to more effectively utilize lignin. To that end, our group aims to synthesize and characterize a collection of inorganic and organometallic catalysts to promote atom-economical catalytic lignin depolymerization. These catalysts have been screened against a continuum of model compounds and biomass-derived lignin for their usefulness in the deconstruction of these substrates. In addition, we have coupled our experimental efforts with quantum mechanical calculations to elucidate the mechanisms of catalysts to identify the mechanisms of lignin depolymerization. Detailed synthetic procedures, as well as spectroscopic and crystallographic characterization and DFT calculations will be presented.

  11. Tandem Catalytic Depolymerization of Lignin by Water-Tolerant Lewis Acids and Rhodium Complexes.

    PubMed

    Jastrzebski, Robin; Constant, Sandra; Lancefield, Christopher S; Westwood, Nicholas J; Weckhuysen, Bert M; Bruijnincx, Pieter C A

    2016-08-23

    Lignin is an attractive renewable feedstock for aromatic bulk and fine chemicals production, provided that suitable depolymerization procedures are developed. Here, we describe a tandem catalysis strategy for ether linkage cleavage within lignin, involving ether hydrolysis by water-tolerant Lewis acids followed by aldehyde decarbonylation by a Rh complex. In situ decarbonylation of the reactive aldehydes limits loss of monomers by recondensation, a major issue in acid-catalyzed lignin depolymerization. Rate of hydrolysis and decarbonylation were matched using lignin model compounds, allowing the method to be successfully applied to softwood, hardwood, and herbaceous dioxasolv lignins, as well as poplar sawdust, to give the anticipated decarbonylation products and, rather surprisingly, 4-(1-propenyl)phenols. Promisingly, product selectivity can be tuned by variation of the Lewis-acid strength and lignin source. PMID:27440544

  12. Approaches to the selective catalytic conversion of lignin: a grand challenge for biorefinery development.

    PubMed

    Bozell, Joseph J

    2014-01-01

    Lignin comprises 15-25% of terrestrial biomass and is the second most abundant source of renewable carbon after cellulose. However, its structural heterogeneity frustrates efforts for its selective conversion into biobased chemicals. Catalyst design for lignin transformation offers an opportunity to improve selectivity, and, hence, improve lignin's utility as a raw material in chemical production. Catalytic deconstruction and conversion of lignin has been examined using a variety of thermochemical treatments, analogous to those used in the petrochemical industry. However, the complex nature of these products limits their utility. More recently, greater focus has been given to an understanding of lignin's molecular level structure, and designing catalysts that can be targeted to key individual structural units within the biopolymer. This review gives a sense of the field by providing a representative description of recent developments in some of the primary technologies employed for lignin conversion and approaches that promise to improve selectivity. PMID:24696353

  13. Biomass pretreatments capable of enabling lignin valorization in a biorefinery process.

    PubMed

    Narron, Robert H; Kim, Hoyong; Chang, Hou-Min; Jameel, Hasan; Park, Sunkyu

    2016-04-01

    Recent techno-economic studies of proposed lignocellulosic biorefineries have concluded that creating value from lignin will assist realization of biomass utilization into valuable fuels, chemicals, and materials due to co-valorization and the new revenues beyond carbohydrates. The pretreatment step within a biorefinery process is essential for recovering carbohydrates, but different techniques and intensities have a variety of effects on lignin. Acidic and alkaline pretreatments have been shown to produce diverse lignins based on delignification chemistry. The valorization potential of pretreated lignin is affected by its chemical structure, which is known to degrade, including inter-lignin condensation under high-severity pretreatment. Co-valorization of lignin and carbohydrates will require dampening of pretreatment intensities to avoid such effects, in spite of tradeoffs in carbohydrate production. PMID:26780496

  14. Structural characterization of the lignin in the cortex and pith of elephant grass (Pennisetum purpureum) stems.

    PubMed

    del Río, José C; Prinsen, Pepijn; Rencoret, Jorge; Nieto, Lidia; Jiménez-Barbero, Jesús; Ralph, John; Martínez, Angel T; Gutiérrez, Ana

    2012-04-11

    The structure of the lignin in the cortex and pith of elephant grass (Pennisetum purpureum) stems was studied both in situ and in isolated milled "wood" lignins by several analytical methods. The presence of p-coumarate and ferulate in the cortex and pith, as well as in their isolated lignins, was revealed by pyrolysis in the presence of tetramethylammonium hydroxide, and by 2D NMR, and indicated that ferulate acylates the carbohydrates while p-coumarate acylates the lignin polymer. 2D NMR showed a predominance of alkyl aryl ether (β-O-4') linkages (82% of total interunit linkages), with low amounts of "condensed" substructures, such as resinols (β-β'), phenylcoumarans (β-5'), and spirodienones (β-1'). Moreover, the NMR also indicated that these lignins are extensively acylated at the γ-carbon of the side chain. DFRC analyses confirmed that p-coumarate groups acylate the γ-OHs of these lignins, and predominantly on syringyl units. PMID:22414389

  15. Synthesis and properties of lignin peroxidase from Streptomyces viridosporus T7A

    SciTech Connect

    Lodha, S.J.; Korus, R.A.; Crawford, D.L.

    1991-12-31

    The production of lignin peroxidase by Streptomyces viridosporus T7A was studied in shake flasks and under aerobic conditions in a 7.5-L batch fermentor. Lignin peroxidase synthesis was found to be strongly affected by catabolite repression. Lignin peroxidase was a non-growth-associated, secondary metabolite. The maximum lignin peroxidase activity was 0.064 U/mL at 36 h. In order to maximize lignin peroxidase activity, optimal conditions were determined. The optimal incubation temperature, pH, and substrate (2,4-dichlorophenol) concentration for the enzyme assays were 45{degrees}C, 6, and 3 m-M, respectively. Stability of lignin peroxidase was determined at 37, 45, and 60{degrees}C, and over the pH range 4-9.

  16. The emerging role for bacteria in lignin degradation and bio-product formation.

    PubMed

    Bugg, Timothy D H; Ahmad, Mark; Hardiman, Elizabeth M; Singh, Rahul

    2011-06-01

    The microbial degradation of lignin has been well studied in white-rot and brown-rot fungi, but is much less well studied in bacteria. Recent published work suggests that a range of soil bacteria, often aromatic-degrading bacteria, are able to break down lignin. The enzymology of bacterial lignin breakdown is currently not well understood, but extracellular peroxidase and laccase enzymes appear to be involved. There are also reports of aromatic-degrading bacteria isolated from termite guts, though there are conflicting reports on the ability of termite gut micro-organisms to break down lignin. If biocatalytic routes for lignin breakdown could be developed, then lignin represents a potentially rich source of renewable aromatic chemicals. PMID:21071202

  17. Cation-pi interactions as a mechanism in technical lignin adsorption to cationic surfaces.

    PubMed

    Pillai, Karthik V; Renneckar, Scott

    2009-04-13

    The assembly of dissolved technical lignins in aqueous and organic medium has been studied at the solid-liquid interface. Adsorption of alkali lignin onto gold coated crystals treated with a cationic polymer was determined using a quartz crystal microbalance with dissipation monitoring. Complete coverage of the cationic surface with alkali lignin occurred at low solution concentration, revealing a high affinity coefficient under both alkali and neutral conditions. With additional adsorption studies from organosolv lignin in organic solvent and spectroscopic analysis of mixtures of cationic polymer and alkali lignin, a noncovalent interaction between lignin's aromatic rings and the cation of the quaternary ammonium group was shown to exist. The work underscores how polyphenolic biopolymers can strongly interact with cations through noncovalent interactions to control molecular architecture. PMID:19226174

  18. Polymeric materials in Space

    NASA Astrophysics Data System (ADS)

    Skurat, Vladimir

    Paper of short review type. It is the continuation of and addition to previous review papers "V. E. Skurat. Polymers in Space. In: Encyclopedia of aerospace engineering, vol. 4, Wiley and sons, 2010; Ibid., 2012 (on line)". Following topics are considered: (1) Destruction of polymers by solar radiation with various wavelengths in different spectral regions (visible-UV, vacuum UV (VUV), deep UV, soft and hard X-rays) are discussed. In difference with common polymer photochemistry induced by UV radiation, directions of various routs of polymer phototransformations and their relative yields are greatly dependent on wavelength of light (photon energy) during illuminations in VUV, deep UV and X-ray regions. During last twenty years, intensive spacecraft investigations of solar spectrum show great periodic and spontaneous variations of radiation intensities in short-wavelengths regions - up to one - two decimal orders of magnitude for X-rays. As a result, during solar flares the absorbed dose on the polymer surfaces from X-rays can be compared with absorbed dose from VUV radiation. (2) Some new approaches to predictions of reaction efficiencies of fast orbital atomic oxygen in their interaction with polymeric materials are considered. (3) Some aspects of photocatalitic destruction of polymers in vacuum conditions by full-spectrum solar radiation are discussed. This process can take place in enamels containing semiconducting particles (TiO2, ZnO) as pigments. (4) Contamination of spacecraft surfaces from intrinsic outer atmosphere play important role not only from the point of view of deterioration of optical and thermophysical properties. Layers of SiO2 contaminations with nanometer thicknesses can greatly diminish mass losses from perfluorinated polymers under VUV irradiation.

  19. Polymeric materials for neovascularization

    NASA Astrophysics Data System (ADS)

    DeVolder, Ross John

    Revascularization therapies have emerged as a promising strategy to treat various acute and chronic wounds, cardiovascular diseases, and tissue defects. It is common to either administer proangiogenic growth factors, such as vascular endothelial growth factor (VEGF), or transplant cells that endogenously express multiple proangiogenic factors. Additionally, these strategies utilize a wide variety of polymeric systems, including hydrogels and biodegradable plastics, to deliver proangiogenic factors in a sophisticated manner to maintain a sustained proangiogenic environment. Despite some impressive results in rebuilding vascular networks, it is still a challenging task to engineer mature and functional neovessels in target tissues, because of the increasing complexities involved with neovascularization applications. To resolve these challenges, this work aims to design a wide variety of proangiogenic biomaterial systems with tunable properties used for neovascularization therapies. This thesis describes the design of several biomaterial systems used for the delivery of proangiogenic factors in neovascularization therapies, including: an electrospun/electrosprayed biodegradable plastic patch used for directional blood vessel growth (Chapter 2), an alginate-g-pyrrole hydrogel system that biochemically stimulates cellular endogenous proangiogenic factor expression (Chapter 3), an enzyme-catalyzed alginate-g-pyrrole hydrogel system for VEGF delivery (Chapter 4), an enzyme-activated alginate-g-pyrrole hydrogel system with systematically controllable electrical and mechanical properties (Chapter 5), and an alginate-g-pyrrole hydrogel that enables the decoupled control of electrical conductivity and mechanical rigidity and is use to electrically stimulate cellular endogenous proangiogenic factor expression (Chapter 6). Overall, the biomaterial systems developed in this thesis will be broadly useful for improving the quality of a wide array of molecular and cellular based

  20. On-line measurement of lignin in wood pulp by color shift of fluorescence

    DOEpatents

    Jeffers, Larry A.; Malito, Michael L.

    1996-01-01

    Lignin concentrations from wood pulp samples are measured by applying an excitation light at a selected wavelength to the samples in order to cause the lignin to emit fluorescence. A spectral distribution of the fluorescence emission is then determined. The lignin concentration is then calculated based on the spectral distribution signal. The spectral distribution is quantified by either a wavelength centroid method or a band ratio method.