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Sample records for lignin biosynthetic pathway

  1. Vanillin biosynthetic pathways in plants.

    Science.gov (United States)

    Kundu, Anish

    2017-06-01

    The present review compiles the up-to-date knowledge on vanillin biosynthesis in plant systems to focus principally on the enzymatic reactions of in planta vanillin biosynthetic pathway and to find out its impact and prospect in future research in this field. Vanillin, a very popular flavouring compound, is widely used throughout the world. The principal natural resource of vanillin is the cured vanilla pods. Due to the high demand of vanillin as a flavouring agent, it is necessary to explore its biosynthetic enzymes and genes, so that improvement in its commercial production can be achieved through metabolic engineering. In spite of significant advancement in elucidating vanillin biosynthetic pathway in the last two decades, no conclusive demonstration had been reported yet for plant system. Several biosynthetic enzymes have been worked upon but divergences in published reports, particularly in characterizing the crucial biochemical steps of vanillin biosynthesis, such as side-chain shortening, methylation, and glucoside formation and have created a space for discussion. Recently, published reviews on vanillin biosynthesis have focused mainly on the biotechnological approaches and bioconversion in microbial systems. This review, however, aims to compile in brief the overall vanillin biosynthetic route and present a comparative as well as comprehensive description of enzymes involved in the pathway in Vanilla planifolia and other plants. Special emphasis has been given on the key enzymatic biochemical reactions that have been investigated extensively. Finally, the present standpoint and future prospects have been highlighted.

  2. The simultaneous repression of CCR and CAD, two enzymes of the lignin biosynthetic pathway, results in sterility and dwarfism in Arabidopsis thaliana.

    Science.gov (United States)

    Thévenin, Johanne; Pollet, Brigitte; Letarnec, Bruno; Saulnier, Luc; Gissot, Lionel; Maia-Grondard, Alessandra; Lapierre, Catherine; Jouanin, Lise

    2011-01-01

    Cinnamoyl CoA reductase (CCR) and cinnamyl alcohol dehydrogenase (CAD) catalyze the last steps of monolignol biosynthesis. In Arabidopsis, one CCR gene (CCR1, At1g15950) and two CAD genes (CAD C At3g19450 and CAD D At4g34230) are involved in this pathway. A triple cad c cad d ccr1 mutant, named ccc, was obtained. This mutant displays a severe dwarf phenotype and male sterility. The lignin content in ccc mature stems is reduced to 50% of the wild-type level. In addition, stem lignin structure is severely affected, as shown by the dramatic enrichment in resistant inter-unit bonds and incorporation into the polymer of monolignol precursors such as coniferaldehyde, sinapaldehyde, and ferulic acid. Male sterility is due to the lack of lignification in the anther endothecium, which causes the failure of anther dehiscence and of pollen release. The ccc hypolignified stems accumulate higher amounts of flavonol glycosides, sinapoyl malate and feruloyl malate, which suggests a redirection of the phenolic pathway. Therefore, the absence of CAD and CCR, key enzymes of the monolignol pathway, has more severe consequences on the phenotype than the individual absence of each of them. Induction of another CCR (CCR2, At1g80820) and another CAD (CAD1, At4g39330) does not compensate the absence of the main CCR and CAD activities. This lack of CCR and CAD activities not only impacts lignification, but also severely affects the development of the plants. These consequences must be carefully considered when trying to reduce the lignin content of plants in order to facilitate the lignocellulose-to-bioethanol conversion process.

  3. Biosynthetic Pathways of Ergot Alkaloids

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    Nina Gerhards

    2014-12-01

    Full Text Available Ergot alkaloids are nitrogen-containing natural products belonging to indole alkaloids. The best known producers are fungi of the phylum Ascomycota, e.g., Claviceps, Epichloë, Penicillium and Aspergillus species. According to their structures, ergot alkaloids can be divided into three groups: clavines, lysergic acid amides and peptides (ergopeptines. All of them share the first biosynthetic steps, which lead to the formation of the tetracyclic ergoline ring system (except the simplest, tricyclic compound: chanoclavine. Different modifications on the ergoline ring by specific enzymes result in an abundance of bioactive natural products, which are used as pharmaceutical drugs or precursors thereof. From the 1950s through to recent years, most of the biosynthetic pathways have been elucidated. Gene clusters from several ergot alkaloid producers have been identified by genome mining and the functions of many of those genes have been demonstrated by knock-out experiments or biochemical investigations of the overproduced enzymes.

  4. Targeting the GPI biosynthetic pathway.

    Science.gov (United States)

    Yadav, Usha; Khan, Mohd Ashraf

    2018-02-27

    The GPI (Glycosylphosphatidylinositol) biosynthetic pathway is a multistep conserved pathway in eukaryotes that culminates in the generation of GPI glycolipid which in turn anchors many proteins (GPI-APs) to the cell surface. In spite of the overall conservation of the pathway, there still exist subtle differences in the GPI pathway of mammals and other eukaryotes which holds a great promise so far as the development of drugs/inhibitors against specific targets in the GPI pathway of pathogens is concerned. Many of the GPI structures and their anchored proteins in pathogenic protozoans and fungi act as pathogenicity factors. Notable examples include GPI-anchored variant surface glycoprotein (VSG) in Trypanosoma brucei, GPI-anchored merozoite surface protein 1 (MSP1) and MSP2 in Plasmodium falciparum, protein-free GPI related molecules like lipophosphoglycans (LPGs) and glycoinositolphospholipids (GIPLs) in Leishmania spp., GPI-anchored Gal/GalNAc lectin and proteophosphoglycans in Entamoeba histolytica or the GPI-anchored mannoproteins in pathogenic fungi like Candida albicans. Research in this active area has already yielded encouraging results in Trypanosoma brucei by the development of parasite-specific inhibitors of GlcNCONH 2 -β-PI, GlcNCONH 2 -(2-O-octyl)-PI and salicylic hydroxamic acid (SHAM) targeting trypanosomal GlcNAc-PI de-N-acetylase as well as the development of antifungal inhibitors like BIQ/E1210/gepinacin/G365/G884 and YW3548/M743/M720 targeting the GPI specific fungal inositol acyltransferase (Gwt1) and the phosphoethanolamine transferase-I (Mcd4), respectively. These confirm the fact that the GPI pathway continues to be the focus of researchers, given its implications for the betterment of human life.

  5. Genes encoding enzymes of the lignin biosynthesis pathway in Eucalyptus

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    Ricardo Harakava

    2005-01-01

    Full Text Available Eucalyptus ESTs libraries were screened for genes involved in lignin biosynthesis. This search was performed under the perspective of recent revisions on the monolignols biosynthetic pathway. Eucalyptus orthologues of all genes of the phenylpropanoid pathway leading to lignin biosynthesis reported in other plant species were identified. A library made with mRNAs extracted from wood was enriched for genes involved in lignin biosynthesis and allowed to infer the isoforms of each gene family that play a major role in wood lignin formation. Analysis of the wood library suggests that, besides the enzymes of the phenylpropanoids pathway, chitinases, laccases, and dirigent proteins are also important for lignification. Colocalization of several enzymes on the endoplasmic reticulum membrane, as predicted by amino acid sequence analysis, supports the existence of metabolic channeling in the phenylpropanoid pathway. This study establishes a framework for future investigations on gene expression level, protein expression and enzymatic assays, sequence polymorphisms, and genetic engineering.

  6. Molecular evolution of the lysine biosynthetic pathways.

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    Velasco, A M; Leguina, J I; Lazcano, A

    2002-10-01

    Among the different biosynthetic pathways found in extant organisms, lysine biosynthesis is peculiar because it has two different anabolic routes. One is the diaminopimelic acid pathway (DAP), and the other over the a-aminoadipic acid route (AAA). A variant of the AAA route that includes some enzymes involved in arginine and leucine biosyntheses has been recently reported in Thermus thermophilus (Nishida et al. 1999). Here we describe the results of a detailed genomic analysis of each of the sequences involved in the two lysine anabolic routes, as well as of genes from other routes related to them. No evidence was found of an evolutionary relationship between the DAP and AAA enzymes. Our results suggest that the DAP pathway is related to arginine metabolism, since the lysC, asd, dapC, dapE, and lysA genes from lysine biosynthesis are related to the argB, argC, argD, argE, and speAC genes, respectively, whose products catalyze different steps in arginine metabolism. This work supports previous reports on the relationship between AAA gene products and some enzymes involved in leucine biosynthesis and the tricarboxylic acid cycle (Irvin and Bhattacharjee 1998; Miyazaki et al. 2001). Here we discuss the significance of the recent finding that several genes involved in the arginine (Arg) and leucine (Leu) biosynthesis participate in a new alternative route of the AAA pathway (Miyazaki et al. 2001). Our results demonstrate a clear relationship between the DAP and Arg routes, and between the AAA and Leu pathways.

  7. Heterologous Expression of the Oxytetracycline Biosynthetic Pathway in Myxococcus xanthus▿

    Science.gov (United States)

    Stevens, D. Cole; Henry, Michael R.; Murphy, Kimberly A.; Boddy, Christopher N.

    2010-01-01

    New natural products for drug discovery may be accessed by heterologous expression of bacterial biosynthetic pathways in metagenomic DNA libraries. However, a “universal” host is needed for this experiment. Herein, we show that Myxococcus xanthus is a potential “universal” host for heterologous expression of polyketide biosynthetic gene clusters. PMID:20208031

  8. Biosynthetic Pathway and Metabolic Engineering of Plant Dihydrochalcones.

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    Ibdah, Mwafaq; Martens, Stefan; Gang, David R

    2018-03-14

    Dihydrochalcones are plant natural products containing the phenylpropanoid backbone and derived from the plant-specific phenylpropanoid pathway. Dihydrochalcone compounds are important in plant growth and response to stresses and, thus, can have large impacts on agricultural activity. In recent years, these compounds have also received increased attention from the biomedical community for their potential as anticancer treatments and other benefits for human health. However, they are typically produced at relatively low levels in plants. Therefore, an attractive alternative is to express the plant biosynthetic pathway genes in microbial hosts and to engineer the metabolic pathway/host to improve the production of these metabolites. In the present review, we discuss in detail the functions of genes and enzymes involved in the biosynthetic pathway of the dihydrochalcones and the recent strategies and achievements used in the reconstruction of multi-enzyme pathways in microorganisms in efforts to be able to attain higher amounts of desired dihydrochalcones.

  9. Bioengineering natural product biosynthetic pathways for therapeutic applications.

    Science.gov (United States)

    Wu, Ming-Cheng; Law, Brian; Wilkinson, Barrie; Micklefield, Jason

    2012-12-01

    With the advent of next-generation DNA sequencing technologies, the number of microbial genome sequences has increased dramatically, revealing a vast array of new biosynthetic gene clusters. Genomics data provide a tremendous opportunity to discover new natural products, and also to guide the bioengineering of new and existing natural product scaffolds for therapeutic applications. Notably, it is apparent that the vast majority of biosynthetic gene clusters are either silent or produce very low quantities of the corresponding natural products. It is imperative therefore to devise methods for activating unproductive biosynthetic pathways to provide the quantities of natural products needed for further development. Moreover, on the basis of our expanding mechanistic and structural knowledge of biosynthetic assembly-line enzymes, new strategies for re-programming biosynthetic pathways have emerged, resulting in focused libraries of modified products with potentially improved biological properties. In this review we will focus on the latest bioengineering approaches that have been utilised to optimise yields and increase the structural diversity of natural product scaffolds for future clinical applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Elucidation and in planta reconstitution of the parthenolide biosynthetic pathway

    DEFF Research Database (Denmark)

    Liu, Qing; Manzano, David; Tanić, Nikola

    2014-01-01

    Parthenolide, the main bioactive compound of the medicinal plant feverfew (Tanacetum parthenium), is a promising anti-cancer drug. However, the biosynthetic pathway of parthenolide has not been elucidated yet. Here we report on the isolation and characterization of all the genes from feverfew tha...

  11. [Advance in flavonoids biosynthetic pathway and synthetic biology].

    Science.gov (United States)

    Zou, Li-Qiu; Wang, Cai-Xia; Kuang, Xue-Jun; Li, Ying; Sun, Chao

    2016-11-01

    Flavonoids are the valuable components in medicinal plants, which possess a variety of pharmacological activities, including anti-tumor, antioxidant and anti-inflammatory activities. There is an unambiguous understanding about flavonoids biosynthetic pathway, that is,2S-flavanones including naringenin and pinocembrin are the skeleton of other flavonoids and they can transform to other flavonoids through branched metabolic pathway. Elucidation of the flavonoids biosynthetic pathway lays a solid foundation for their synthetic biology. A few flavonoids have been produced in Escherichia coli or yeast with synthetic biological technologies, such as naringenin, pinocembrin and fisetin. Synthetic biology will provide a new way to get valuable flavonoids and promote the research and development of flavonoid drugs and health products, making flavonoids play more important roles in human diet and health. Copyright© by the Chinese Pharmaceutical Association.

  12. A kinetic model for the penicillin biosynthetic pathway in

    DEFF Research Database (Denmark)

    Nielsen, Jens; Jørgensen, Henrik

    1996-01-01

    A kinetic model for the first two steps in the penicillin biosynthetic pathway, i.e. the ACV synthetase (ACVS) and the isopenicillin N synthetase (IPNS) is proposed. The model is based on Michaelis-Menten type kinetics with non-competitive inhibition of the ACVS by ACV, and competitive inhibition...... of the IPNS by glutathione. The model predicted flux through the pathway corresponds well with the measured rate of penicillin biosynthesis. From the kinetic model the elasticity coefficients and the flux control coefficients are calculated throughout a fed-batch cultivation, and it is found...

  13. Cell wall composition and lignin biosynthetic gene expression along a developmental gradient in an Australian sugarcane cultivar

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    William P. Bewg

    2017-12-01

    Full Text Available Sugarcane bagasse is an abundant source of lignocellulosic material for bioethanol production. Utilisation of bagasse for biofuel production would be environmentally and economically beneficial, but the recalcitrance of lignin continues to provide a challenge. Further understanding of lignin production in specific cultivars will provide a basis for modification of genomes for the production of phenotypes with improved processing characteristics. Here we evaluated the expression profile of lignin biosynthetic genes and the cell wall composition along a developmental gradient in KQ228 sugarcane. The expression levels of nine lignin biosynthesis genes were quantified in five stem sections of increasing maturity and in root tissue. Two distinct expression patterns were seen. The first saw highest gene expression in the youngest tissue, with expression decreasing as tissue matured. The second pattern saw little to no change in transcription levels across the developmental gradient. Cell wall compositional analysis of the stem sections showed total lignin content to be significantly higher in more mature tissue than in the youngest section assessed. There were no changes in structural carbohydrates across developmental sections. These gene expression and cell wall compositional patterns can be used, along with other work in grasses, to inform biotechnological approaches to crop improvement for lignocellulosic biofuel production.

  14. Metabolic engineering of biosynthetic pathway for production of renewable biofuels.

    Science.gov (United States)

    Singh, Vijai; Mani, Indra; Chaudhary, Dharmendra Kumar; Dhar, Pawan Kumar

    2014-02-01

    Metabolic engineering is an important area of research that involves editing genetic networks to overproduce a certain substance by the cells. Using a combination of genetic, metabolic, and modeling methods, useful substances have been synthesized in the past at industrial scale and in a cost-effective manner. Currently, metabolic engineering is being used to produce sufficient, economical, and eco-friendly biofuels. In the recent past, a number of efforts have been made towards engineering biosynthetic pathways for large scale and efficient production of biofuels from biomass. Given the adoption of metabolic engineering approaches by the biofuel industry, this paper reviews various approaches towards the production and enhancement of renewable biofuels such as ethanol, butanol, isopropanol, hydrogen, and biodiesel. We have also identified specific areas where more work needs to be done in the future.

  15. The flavonoid biosynthetic pathway in plants: function and evolution

    International Nuclear Information System (INIS)

    Koes, R.E.; Quattrocchio, F.; Mol, J.N.M.

    1994-01-01

    Flavonoids are a class of low molecular weight phenolic compounds that is widely distributed in the plant kingdom. They exhibit a diverse spectrum of biological functions and play an important role in the interaction between plants and their environment. Flavonoids not only protect the plant from the harmful effects of UV irradiation but also play a crucial role in the sexual reproduction process. A special class of flavonoid polymers, the tannins, plays a structural role in the plant. Yet other classes of flavonoids, flavonols and anthocyanins, have been implicated in the attraction of pollinators. Certain flavonoids participate in the interaction between plants and other organisms such as symbiotic bacteria and parasites. This raises the intriguing question as to how these different compounds arose and evolved. Based on taxonomy and molecular analysis of gene expression patterns it is possible to deduce a putative sequence of acquisition of the different branches of the biosynthetic pathway and their regulators. (author)

  16. The flavonoid biosynthetic pathway in plants: function and evolution

    Energy Technology Data Exchange (ETDEWEB)

    Koes, R. E.; Quattrocchio, F.; Mol, J. N.M. [Department of Genetics, Institute for Molecular Biological Sciences, Vrije Universiteit, BioCentrum Amsterdam, De Boelelaan 1087, 1081HV, Amsterdam (Netherlands)

    1994-07-01

    Flavonoids are a class of low molecular weight phenolic compounds that is widely distributed in the plant kingdom. They exhibit a diverse spectrum of biological functions and play an important role in the interaction between plants and their environment. Flavonoids not only protect the plant from the harmful effects of UV irradiation but also play a crucial role in the sexual reproduction process. A special class of flavonoid polymers, the tannins, plays a structural role in the plant. Yet other classes of flavonoids, flavonols and anthocyanins, have been implicated in the attraction of pollinators. Certain flavonoids participate in the interaction between plants and other organisms such as symbiotic bacteria and parasites. This raises the intriguing question as to how these different compounds arose and evolved. Based on taxonomy and molecular analysis of gene expression patterns it is possible to deduce a putative sequence of acquisition of the different branches of the biosynthetic pathway and their regulators. (author)

  17. Overexpression of the riboflavin biosynthetic pathway in Pichia pastoris

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    Mattanovich Diethard

    2008-07-01

    Full Text Available Abstract Background High cell density cultures of Pichia pastoris grown on methanol tend to develop yellow colored supernatants, attributed to the release of free flavins. The potential of P. pastoris for flavin overproduction is therefore given, but not pronounced when the yeast is grown on glucose. The aim of this study is to characterize the relative regulatory impact of each riboflavin synthesis gene. Deeper insight into pathway control and the potential of deregulation is established by overexpression of the single genes as well as a combined deregulation of up to all six riboflavin synthesis genes. Results Overexpression of the first gene of the riboflavin biosynthetic pathway (RIB1 is already sufficient to obtain yellow colonies and the accumulation of riboflavin in the supernatant of shake flask cultures growing on glucose. Sequential deregulation of all the genes, by exchange of their native promoter with the strong and constitutive glyceraldehyde-3-phosphate dehydrogenase promoter (PGAP increases the riboflavin accumulation significantly. Conclusion The regulation of the pathway is distributed over more than one gene. High cell density cultivations of a P. pastoris strain overexpressing all six RIB genes allow the accumulation of 175 mg/L riboflavin in the supernatant. The basis for rational engineering of riboflavin production in P. pastoris has thus been established.

  18. Genetic engineering of syringyl-enriched lignin in plants

    Science.gov (United States)

    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.

  19. Reconstruction of cytosolic fumaric acid biosynthetic pathways in Saccharomyces cerevisiae

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    Xu Guoqiang

    2012-02-01

    Full Text Available Abstract Background Fumaric acid is a commercially important component of foodstuffs, pharmaceuticals and industrial materials, yet the current methods of production are unsustainable and ecologically destructive. Results In this study, the fumarate biosynthetic pathway involving reductive reactions of the tricarboxylic acid cycle was exogenously introduced in S. cerevisiae by a series of simple genetic modifications. First, the Rhizopus oryzae genes for malate dehydrogenase (RoMDH and fumarase (RoFUM1 were heterologously expressed. Then, expression of the endogenous pyruvate carboxylase (PYC2 was up-regulated. The resultant yeast strain, FMME-001 ↑PYC2 + ↑RoMDH, was capable of producing significantly higher yields of fumarate in the glucose medium (3.18 ± 0.15 g liter-1 than the control strain FMME-001 empty vector. Conclusions The results presented here provide a novel strategy for fumarate biosynthesis, which represents an important advancement in producing high yields of fumarate in a sustainable and ecologically-friendly manner.

  20. Reconstruction of the biosynthetic pathway for the core fungal polyketide scaffold rubrofusarin in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Rugbjerg, Peter; Naesby, Michael; Mortensen, Uffe Hasbro

    2013-01-01

    production in easily fermentable and genetically engineerable organisms, such as Saccharomyces cerevisiae and Escherichia coli are desirable. Rubrofusarin is an orange polyketide pigment that is a common intermediate in many different fungal biosynthetic pathways. RESULTS: In this study, we established...

  1. A nitrous acid biosynthetic pathway for diazo group formation in bacteria.

    Science.gov (United States)

    Sugai, Yoshinori; Katsuyama, Yohei; Ohnishi, Yasuo

    2016-02-01

    Although some diazo compounds have bioactivities of medicinal interest, little is known about diazo group formation in nature. Here we describe an unprecedented nitrous acid biosynthetic pathway responsible for the formation of a diazo group in the biosynthesis of the ortho-diazoquinone secondary metabolite cremeomycin in Streptomyces cremeus. This finding provides important insights into the biosynthetic pathways not only for diazo compounds but also for other naturally occurring compounds containing nitrogen-nitrogen bonds.

  2. Differential hexosamine biosynthetic pathway gene expression with type 2 diabetes

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    Megan Coomer

    2014-01-01

    Full Text Available The hexosamine biosynthetic pathway (HBP culminates in the attachment of O-linked β-N-acetylglucosamine (O-GlcNAc onto serine/threonine residues of target proteins. The HBP is regulated by several modulators, i.e. O-linked β-N-acetylglucosaminyl transferase (OGT and β-N-acetylglucosaminidase (OGA catalyze the addition and removal of O-GlcNAc moieties, respectively; while flux is controlled by the rate-limiting enzyme glutamine:fructose-6-phosphate amidotransferase (GFPT, transcribed by two genes, GFPT1 and GFPT2. Since increased HBP flux is glucose-responsive and linked to insulin resistance/type 2 diabetes onset, we hypothesized that diabetic individuals exhibit differential expression of HBP regulatory genes. Volunteers (n = 60; n = 20 Mixed Ancestry, n = 40 Caucasian were recruited from Stellenbosch and Paarl (Western Cape, South Africa and classified as control, pre- or diabetic according to fasting plasma glucose and HbA1c levels, respectively. RNA was purified from leukocytes isolated from collected blood samples and OGT, OGA, GFPT1 and GFPT2 expressions determined by quantitative real-time PCR. The data reveal lower OGA expression in diabetic individuals (P < 0.01, while pre- and diabetic subjects displayed attenuated OGT expression vs. controls (P < 0.01 and P < 0.001, respectively. Moreover, GFPT2 expression decreased in pre- and diabetic Caucasians vs. controls (P < 0.05 and P < 0.01, respectively. We also found ethnic differences, i.e. Mixed Ancestry individuals exhibited a 2.4-fold increase in GFPT2 expression vs. Caucasians, despite diagnosis (P < 0.01. Gene expression of HBP regulators differs between diabetic and non-diabetic individuals, together with distinct ethnic-specific gene profiles. Thus differential HBP gene regulation may offer diagnostic utility and provide candidate susceptibility genes for different ethnic groupings.

  3. AP2/ERF Transcription Factor, Ii049, Positively Regulates Lignan Biosynthesis in Isatis indigotica through Activating Salicylic Acid Signaling and Lignan/Lignin Pathway Genes

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    Ruifang Ma

    2017-08-01

    Full Text Available Lignans, such as lariciresinol and its derivatives, have been identified as effective antiviral ingredients in Isatis indigotica. Evidence suggests that the APETALA2/ethylene response factor (AP2/ERF family might be related to the biosynthesis of lignans in I. indigotica. However, the special role played by the AP2/ERF family in the metabolism and its underlying putative mechanism still need to be elucidated. One novel AP2/ERF gene, named Ii049, was isolated and characterized from I. indigotica in this study. The quantitative real-time PCR analysis revealed that Ii049 was expressed highest in the root and responded to methyl jasmonate, salicylic acid (SA and abscisic acid treatments to various degrees. Subcellular localization analysis indicated that Ii049 protein was localized in the nucleus. Knocking-down the expression of Ii049 caused a remarkable reduction of lignan/lignin contents and transcript levels of genes involved in the lignan/lignin biosynthetic pathway. Ii049 bound to the coupled element 1, RAV1AAT and CRTAREHVCBF2 motifs of genes IiPAL and IiCCR, the key structural genes in the lignan/lignin pathway. Furthermore, Ii049 was also essential for SA biosynthesis, and SA induced lignan accumulation in I. indigotica. Notably, the transgenic I. indigotica hairy roots overexpressing Ii049 showed high expression levels of lignan/lignin biosynthetic genes and SA content, resulting in significant accumulation of lignan/lignin. The best-engineered line (OVX049-10 produced 425.60 μg·g−1 lariciresinol, an 8.3-fold increase compared with the wild type production. This study revealed the function of Ii049 in regulating lignan/lignin biosynthesis, which had the potential to increase the content of valuable lignan/lignin in economically significant medicinal plants.

  4. Lignins : natural polymers from oxidative coupling of 4-hydroxyphenyl-propanoids

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    John Ralph; Knut Lundquist; Gosta Brunow; Fachuang Lu; Hoon Kim; Paul F. Schatz; Jane M. Marita; Ronald D. Hatfield; Sally A. Ralph; Jorgen Holst Christensen; Wout Boerjan

    2004-01-01

    Lignins are complex natural polymers resulting from oxidative coupling of, primarily, 4-hydroxyphenylpropanoids. An understanding of their nature is evolving as a result of detailed structural studies, recently aided by the availability of lignin-biosynthetic-pathway mutants and transgenics. The currently accepted theory is that the lignin polymer is formed by...

  5. Stone formation in peach fruit exhibits spatial coordination of the lignin and flavonoid pathways and similarity to Arabidopsis dehiscence

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    Piagnani M Claudia

    2010-02-01

    negative regulator FRUITFUL predominated in exocarp and mesocarp. Conclusions Collectively, the data suggests, first, that the process of endocarp determination and differentiation in peach and Arabidopsis share common regulators and, secondly, reveals a previously unknown coordination of competing lignin and flavonoid biosynthetic pathways during early fruit development.

  6. Dual biosynthetic pathways to phytosterol via cycloartenol and lanosterol in Arabidopsis.

    Science.gov (United States)

    Ohyama, Kiyoshi; Suzuki, Masashi; Kikuchi, Jun; Saito, Kazuki; Muranaka, Toshiya

    2009-01-20

    The differences between the biosynthesis of sterols in higher plants and yeast/mammals are believed to originate at the cyclization step of oxidosqualene, which is cyclized to cycloartenol in higher plants and lanosterol in yeast/mammals. Recently, lanosterol synthase genes were identified from dicotyledonous plant species including Arabidopsis, suggesting that higher plants possess dual biosynthetic pathways to phytosterols via lanosterol, and through cycloartenol. To identify the biosynthetic pathway to phytosterol via lanosterol, and to reveal the contributions to phytosterol biosynthesis via each cycloartenol and lanosterol, we performed feeding experiments by using [6-(13)C(2)H(3)]mevalonate with Arabidopsis seedlings. Applying (13)C-{(1)H}{(2)H} nuclear magnetic resonance (NMR) techniques, the elucidation of deuterium on C-19 behavior of phytosterol provided evidence that small amounts of phytosterol were biosynthesized via lanosterol. The levels of phytosterol increased on overexpression of LAS1, and phytosterols derived from lanosterol were not observed in a LAS1-knockout plant. This is direct evidence to indicate that the biosynthetic pathway for phytosterol via lanosterol exists in plant cells. We designate the biosynthetic pathway to phytosterols via lanosterol "the lanosterol pathway." LAS1 expression is reported to be induced by the application of jasmonate and is thought to have evolved from an ancestral cycloartenol synthase to a triterpenoid synthase, such as beta-amyrin synthase and lupeol synthase. Considering this background, the lanosterol pathway may contribute to the biosynthesis of not only phytosterols, but also steroids as secondary metabolites.

  7. Elucidation of the biosynthetic pathway for the production of the pigment chrysogine by Penicillium chrysogenum

    NARCIS (Netherlands)

    Viggiano, Annarita; Salo, Oleksandr; Ali, Hazrat; Szymanski, Wiktor; Lankhorst, Peter P; Nygård, Yvonne; Bovenberg, Roel A L; Driessen, Arnold J M

    Chrysogine is a yellow pigment produced by Penicillium chrysogenum and other filamentous fungi. Although it was first isolated in 1973, the biosynthetic pathway has so far not been resolved. Here, we show that the deletion of the highly expressed non-ribosomal peptide synthetase (NRPS) gene

  8. Neurosteroid biosynthetic pathway changes in substantia nigra and caudate nucleus in Parkinson's disease

    NARCIS (Netherlands)

    Luchetti, Sabina; Bossers, Koen; Frajese, Giovanni Vanni; Swaab, Dick F.

    2010-01-01

    There is emerging evidence from animal studies for a neuroprotective role of sex steroids in neurodegenerative diseases, but studies in human brain are lacking. We have carried out an extensive study of the neurosteroid biosynthetic pathways in substantia nigra (SN), caudate nucleus (CN) and putamen

  9. Characterization of cyanobacterial hydrocarbon composition and distribution of biosynthetic pathways.

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    R Cameron Coates

    Full Text Available Cyanobacteria possess the unique capacity to naturally produce hydrocarbons from fatty acids. Hydrocarbon compositions of thirty-two strains of cyanobacteria were characterized to reveal novel structural features and insights into hydrocarbon biosynthesis in cyanobacteria. This investigation revealed new double bond (2- and 3-heptadecene and methyl group positions (3-, 4- and 5-methylheptadecane for a variety of strains. Additionally, results from this study and literature reports indicate that hydrocarbon production is a universal phenomenon in cyanobacteria. All cyanobacteria possess the capacity to produce hydrocarbons from fatty acids yet not all accomplish this through the same metabolic pathway. One pathway comprises a two-step conversion of fatty acids first to fatty aldehydes and then alkanes that involves a fatty acyl ACP reductase (FAAR and aldehyde deformylating oxygenase (ADO. The second involves a polyketide synthase (PKS pathway that first elongates the acyl chain followed by decarboxylation to produce a terminal alkene (olefin synthase, OLS. Sixty-one strains possessing the FAAR/ADO pathway and twelve strains possessing the OLS pathway were newly identified through bioinformatic analyses. Strains possessing the OLS pathway formed a cohesive phylogenetic clade with the exception of three Moorea strains and Leptolyngbya sp. PCC 6406 which may have acquired the OLS pathway via horizontal gene transfer. Hydrocarbon pathways were identified in one-hundred-forty-two strains of cyanobacteria over a broad phylogenetic range and there were no instances where both the FAAR/ADO and the OLS pathways were found together in the same genome, suggesting an unknown selective pressure maintains one or the other pathway, but not both.

  10. Effect of overall feedback inhibition in unbranched biosynthetic pathways.

    Science.gov (United States)

    Alves, R; Savageau, M A

    2000-11-01

    We have determined the effects of control by overall feedback inhibition on the systemic behavior of unbranched metabolic pathways with an arbitrary pattern of other feedback inhibitions by using a recently developed numerical generalization of Mathematically Controlled Comparisons, a method for comparing the function of alternative molecular designs. This method allows the rigorous determination of the changes in systemic properties that can be exclusively attributed to overall feedback inhibition. Analytical results show that the unbranched pathway can achieve the same steady-state flux, concentrations, and logarithmic gains with respect to changes in substrate, with or without overall feedback inhibition. The analytical approach also shows that control by overall feedback inhibition amplifies the regulation of flux by the demand for end product while attenuating the sensitivity of the concentrations to the same demand. This approach does not provide a clear answer regarding the effect of overall feedback inhibition on the robustness, stability, and transient time of the pathway. However, the generalized numerical method we have used does clarify the answers to these questions. On average, an unbranched pathway with control by overall feedback inhibition is less sensitive to perturbations in the values of the parameters that define the system. The difference in robustness can range from a few percent to fifty percent or more, depending on the length of the pathway and on the metabolite one considers. On average, overall feedback inhibition decreases the stability margins by a minimal amount (typically less than 5%). Finally, and again on average, stable systems with overall feedback inhibition respond faster to fluctuations in the metabolite concentrations. Taken together, these results show that control by overall feedback inhibition confers several functional advantages upon unbranched pathways. These advantages provide a rationale for the prevalence of this

  11. A simple biosynthetic pathway for large product generation from small substrate amounts

    Science.gov (United States)

    Djordjevic, Marko; Djordjevic, Magdalena

    2012-10-01

    A recently emerging discipline of synthetic biology has the aim of constructing new biosynthetic pathways with useful biological functions. A major application of these pathways is generating a large amount of the desired product. However, toxicity due to the possible presence of toxic precursors is one of the main problems for such production. We consider here the problem of generating a large amount of product from a potentially toxic substrate. To address this, we propose a simple biosynthetic pathway, which can be induced in order to produce a large number of the product molecules, by keeping the substrate amount at low levels. Surprisingly, we show that the large product generation crucially depends on fast non-specific degradation of the substrate molecules. We derive an optimal induction strategy, which allows as much as three orders of magnitude increase in the product amount through biologically realistic parameter values. We point to a recently discovered bacterial immune system (CRISPR/Cas in E. coli) as a putative example of the pathway analysed here. We also argue that the scheme proposed here can be used not only as a stand-alone pathway, but also as a strategy to produce a large amount of the desired molecules with small perturbations of endogenous biosynthetic pathways.

  12. A simple biosynthetic pathway for large product generation from small substrate amounts

    Energy Technology Data Exchange (ETDEWEB)

    Djordjevic, Marko [Institute of Physiology and Biochemistry, Faculty of Biology, University of Belgrade (Serbia); Djordjevic, Magdalena [Institute of Physics Belgrade, University of Belgrade (Serbia)

    2012-10-01

    A recently emerging discipline of synthetic biology has the aim of constructing new biosynthetic pathways with useful biological functions. A major application of these pathways is generating a large amount of the desired product. However, toxicity due to the possible presence of toxic precursors is one of the main problems for such production. We consider here the problem of generating a large amount of product from a potentially toxic substrate. To address this, we propose a simple biosynthetic pathway, which can be induced in order to produce a large number of the product molecules, by keeping the substrate amount at low levels. Surprisingly, we show that the large product generation crucially depends on fast non-specific degradation of the substrate molecules. We derive an optimal induction strategy, which allows as much as three orders of magnitude increase in the product amount through biologically realistic parameter values. We point to a recently discovered bacterial immune system (CRISPR/Cas in E. coli) as a putative example of the pathway analysed here. We also argue that the scheme proposed here can be used not only as a stand-alone pathway, but also as a strategy to produce a large amount of the desired molecules with small perturbations of endogenous biosynthetic pathways. (paper)

  13. A simple biosynthetic pathway for large product generation from small substrate amounts

    International Nuclear Information System (INIS)

    Djordjevic, Marko; Djordjevic, Magdalena

    2012-01-01

    A recently emerging discipline of synthetic biology has the aim of constructing new biosynthetic pathways with useful biological functions. A major application of these pathways is generating a large amount of the desired product. However, toxicity due to the possible presence of toxic precursors is one of the main problems for such production. We consider here the problem of generating a large amount of product from a potentially toxic substrate. To address this, we propose a simple biosynthetic pathway, which can be induced in order to produce a large number of the product molecules, by keeping the substrate amount at low levels. Surprisingly, we show that the large product generation crucially depends on fast non-specific degradation of the substrate molecules. We derive an optimal induction strategy, which allows as much as three orders of magnitude increase in the product amount through biologically realistic parameter values. We point to a recently discovered bacterial immune system (CRISPR/Cas in E. coli) as a putative example of the pathway analysed here. We also argue that the scheme proposed here can be used not only as a stand-alone pathway, but also as a strategy to produce a large amount of the desired molecules with small perturbations of endogenous biosynthetic pathways. (paper)

  14. Distribution of δ-aminolevulinic acid biosynthetic pathways among phototrophic and related bacteria

    International Nuclear Information System (INIS)

    Avissar, Y.J.; Beale, S.I.; Ormerod, J.G.

    1989-01-01

    Two biosynthetic pathways are known for the universal tetrapyrrole precursor, δ-aminolevulinic acid (ALA): condensation of glycine and succinyl-CoA to form ALA with the loss of C-1 of glycine as CO 2 , and conversion of the intact carbon skeleton of glutamate to ALA in a process requiring tRNA Glu , ATP, Mg 2+ , NADPH, and pyridoxal phosphate. The distribution of the two ALA biosynthetic pathways among various bacterial genera was determined, using cell-free extracts obtained from representative organisms. Evidence for the operation of the glutamate pathway was obtained by the measurement of RNase-sensitive label incorporation from glutamate into ALA using 3,4-[ 3 H]glutamate and 1-[ 14 C]glutamate as substrate. The glycine pathway was indicated by RNase-insensitive incorporation of level from 2-[ 14 C]glycine into ALA. The distribution of the two pathways among the bacteria tested was in general agreement with their previously phylogenetic relationships and clearly indicates that the glutamate pathway is the more ancient process, whereas the glycine pathway probably evolved much later. The glutamate pathway is the more widely utilized one among bacteria, while the glycine pathway is apparently limited to the α subgroup of purple bacteria (including Rhodobacter, Rhodospirillum, and Rhizobium). E. coli was found ALA via the glutamate pathway. The ALA-requiring hemA mutant of E. coli was determined to lack the dehydrogenase activity that utilizes glutamyl-tRNA as a substrate

  15. Assembly of a novel biosynthetic pathway for production of the plant flavonoid fisetin in Escherichia coli.

    Science.gov (United States)

    Stahlhut, Steen G; Siedler, Solvej; Malla, Sailesh; Harrison, Scott J; Maury, Jérôme; Neves, Ana Rute; Forster, Jochen

    2015-09-01

    Plant secondary metabolites are an underutilized pool of bioactive molecules for applications in the food, pharma and nutritional industries. One such molecule is fisetin, which is present in many fruits and vegetables and has several potential health benefits, including anti-cancer, anti-viral and anti-aging activity. Moreover, fisetin has recently been shown to prevent Alzheimer's disease in mice and to prevent complications associated with diabetes type I. Thus far the biosynthetic pathway of fisetin in plants remains elusive. Here, we present the heterologous assembly of a novel fisetin pathway in Escherichia coli. We propose a novel biosynthetic pathway from the amino acid, tyrosine, utilizing nine heterologous enzymes. The pathway proceeds via the synthesis of two flavanones never produced in microorganisms before--garbanzol and resokaempferol. We show for the first time a functional biosynthetic pathway and establish E. coli as a microbial platform strain for the production of fisetin and related flavonols. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  16. In silico tools for the analysis of antibiotic biosynthetic pathways

    DEFF Research Database (Denmark)

    Weber, Tilmann

    2014-01-01

    Natural products of bacteria and fungi are the most important source for antimicrobial drug leads. For decades, such compounds were exclusively found by chemical/bioactivity-guided screening approaches. The rapid progress in sequencing technologies only recently allowed the development of novel...... screening methods based on the genome sequences of potential producing organisms. The basic principle of such genome mining approaches is to identify genes, which are involved in the biosynthesis of such molecules, and to predict the products of the identified pathways. Thus, bioinformatics methods...... and tools are crucial for genome mining. In this review, a comprehensive overview is given on programs and databases for the identification and analysis of antibiotic biosynthesis gene clusters in genomic data....

  17. Enzyme organization in the proline biosynthetic pathway of Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Gamper, H; Moses, V

    1974-01-01

    The conversion of glutamic acid to proline by an Escherichia coli extract was studied. The activity was dependent upon the presence of ATP and NADPH and was largely unaffected by the presence of NH/sub 3/ or imidazole. The first two pathway enzymes appear to exist as a complex which stabilizes a labile intermediate postulated as ..gamma..-glutamyl phosphate. Attempted synthesis of this compound was unsuccessful due to its spontaneous cyclization to 2-pyrrolidone 5-carboxylate. Dissociation of the enzyme complex upon dilution of the extract is presumed responsible for an experimentally observed dilution effect. E. coli pro/sub A//sup -/ and pro/sub B//sup -/ auxotroph extracts failed to complement one another in the biosynthesis of proline. This is attributed to the lack of a dynamic equilibrium between the complex and its constituent enzymes. In vivo studies with E. coli showed no evidence for metabolic channeling in the final reaction of proline synthesis, the reduction of ..delta../sup 1/-pyrroline 5-carboxylate.

  18. Genetic determination of the meso-diaminopimelate biosynthetic pathway of mycobacteria.

    OpenAIRE

    Cirillo, J. D.; Weisbrod, T. R.; Banerjee, A.; Bloom, B. R.; Jacobs, W. R.

    1994-01-01

    The increasing incidence of multiple-drug-resistant mycobacterial infections indicates that the development of new methods for treatment of mycobacterial diseases should be a high priority. meso-Diaminopimelic acid (DAP), a key component of a highly immunogenic subunit of the mycobacterial peptidoglycan layer, has been implicated as a potential virulence factor. The mycobacterial DAP biosynthetic pathway could serve as a target for design of new antimycobacterial agents as well as the constru...

  19. Spook and Spookier code for stage-specific components of the ecdysone biosynthetic pathway in Diptera

    DEFF Research Database (Denmark)

    Ono, Hajime; Rewitz, Kim; Shinoda, Tetsu

    2006-01-01

    is eliminated in larvae carrying mutations in molting defective (mld), a gene encoding a nuclear zinc finger protein that is required for production of ecdysone during Drosophila larval development. Intriguingly, mld is not present in the Bombyx mori genome, and we have identified only one spook homolog in both...... Bombyx and Manduca that is expressed in both embryos and larva. These studies suggest an evolutionary split between Diptera and Lepidoptera in how the ecdysone biosynthetic pathway is regulated during development....

  20. Construction of a controllable β-carotene biosynthetic pathway by decentralized assembly strategy in Saccharomyces cerevisiae.

    Science.gov (United States)

    Xie, Wenping; Liu, Min; Lv, Xiaomei; Lu, Wenqiang; Gu, Jiali; Yu, Hongwei

    2014-01-01

    Saccharomyces cerevisiae is an important platform organism for the synthesis of a great number of natural products. However, the assembly of controllable and genetically stable heterogeneous biosynthetic pathways in S. cerevisiae still remains a significant challenge. Here, we present a strategy for reconstructing controllable multi-gene pathways by employing the GAL regulatory system. A set of marker recyclable integrative plasmids (pMRI) was designed for decentralized assembly of pathways. As proof-of-principle, a controllable β-carotene biosynthesis pathway (∼16 kb) was reconstructed and optimized by repeatedly using GAL10-GAL1 bidirectional promoters with high efficiency (80-100%). By controling the switch time of the pathway, production of 11 mg/g DCW of total carotenoids (72.57 mg/L) and 7.41 mg/g DCW of β-carotene was achieved in shake-flask culture. In addition, the engineered yeast strain exhibited high genetic stability after 20 generations of subculture. The results demonstrated a controllable and genetically stable biosynthetic pathway capable of increasing the yield of target products. Furthermore, the strategy presented in this study could be extended to construct other pathways in S. cerevisisae. © 2013 Wiley Periodicals, Inc.

  1. Enhancement of Nucleoside Production in Hirsutella sinensis Based on Biosynthetic Pathway Analysis

    Science.gov (United States)

    Liu, Zhi-Qiang; Zhang, Bo; Lin, Shan; Baker, Peter James; Chen, Mao-Sheng; Xue, Ya-Ping; Wu, Hui; Xu, Feng; Yuan, Shui-Jin; Teng, Yi; Wu, Ling-Fang

    2017-01-01

    To enhance nucleoside production in Hirsutella sinensis, the biosynthetic pathways of purine and pyrimidine nucleosides were constructed and verified. The differential expression analysis showed that purine nucleoside phosphorylase, inosine monophosphate dehydrogenase, and guanosine monophosphate synthase genes involved in purine nucleotide biosynthesis were significantly upregulated 16.56-fold, 8-fold, and 5.43-fold, respectively. Moreover, dihydroorotate dehydrogenase, uridine nucleosidase, uridine/cytidine monophosphate kinase, and inosine triphosphate pyrophosphatase genes participating in pyrimidine nucleoside biosynthesis were upregulated 4.53-fold, 10.63-fold, 4.26-fold, and 5.98-fold, respectively. To enhance the nucleoside production, precursors for synthesis of nucleosides were added based on the analysis of biosynthetic pathways. Uridine and cytidine contents, respectively, reached 5.04 mg/g and 3.54 mg/g when adding 2 mg/mL of ribose, resulting in an increase of 28.6% and 296% compared with the control, respectively. Meanwhile, uridine and cytidine contents, respectively, reached 10.83 mg/g 2.12 mg/g when adding 0.3 mg/mL of uracil, leading to an increase of 176.3% and 137.1%, respectively. This report indicated that fermentation regulation was an effective way to enhance the nucleoside production in H. sinensis based on biosynthetic pathway analysis. PMID:29333435

  2. Final Report: Investigation of Catalytic Pathways for Lignin Breakdown into Monomers and Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Gluckstein, Jeffrey A [ORNL; Hu, Michael Z. [ORNL; Kidder, Michelle [ORNL; McFarlane, Joanna [ORNL; Narula, Chaitanya Kumar [ORNL; Sturgeon, Matthew R [ORNL

    2010-12-01

    Lignin is a biopolymer that comprises up to 35% of woody biomass by dry weight. It is currently underutilized compared to cellulose and hemicellulose, the other two primary components of woody biomass. Lignin has an irregular structure of methoxylated aromatic groups linked by a suite of ether and alkyl bonds which makes it difficult to degrade selectively. However, the aromatic components of lignin also make it promising as a base material for the production of aromatic fuel additives and cyclic chemical feed stocks such as styrene, benzene, and cyclohexanol. Our laboratory research focused on three methods to selectively cleave and deoxygenate purified lignin under mild conditions: acidolysis, hydrogenation and electrocatalysis. (1) Acidolysis was undertaken in CH2Cl2 at room temperature. (2) Hydrogenation was carried out by dissolving lignin and a rhodium catalyst in 1:1 water:methoxyethanol under a 1 atm H2 environment. (3) Electrocatalysis of lignin involved reacting electrically generated hydrogen atoms at a catalytic palladium cathode with lignin dissolved in a solution of aqueous methanol. In all of the experiments, the lignin degradation products were identified and quantified by gas chromatography mass spectroscopy and flame ionization detection. Yields were low, but this may have reflected the difficulty in recovering the various fractions after conversion. The homogeneous hydrogenation of lignin showed fragmentation into monomers, while the electrocatalytic hydrogenation showed production of polyaromatic hydrocarbons and substituted benzenes. In addition to the experiments, promising pathways for the conversion of lignin were assessed. Three conversion methods were compared based on their material and energy inputs and proposed improvements using better catalyst and process technology. A variety of areas were noted as needing further experimental and theoretical effort to increase the feasibility of lignin conversion to fuels.

  3. Linking metabolic QTLs with network and cis-eQTLs controlling biosynthetic pathways.

    Directory of Open Access Journals (Sweden)

    Adam M Wentzell

    2007-09-01

    Full Text Available Phenotypic variation between individuals of a species is often under quantitative genetic control. Genomic analysis of gene expression polymorphisms between individuals is rapidly gaining popularity as a way to query the underlying mechanistic causes of variation between individuals. However, there is little direct evidence of a linkage between global gene expression polymorphisms and phenotypic consequences. In this report, we have mapped quantitative trait loci (QTLs-controlling glucosinolate content in a population of 403 Arabidopsis Bay x Sha recombinant inbred lines, 211 of which were previously used to identify expression QTLs controlling the transcript levels of biosynthetic genes. In a comparative study, we have directly tested two plant biosynthetic pathways for association between polymorphisms controlling biosynthetic gene transcripts and the resulting metabolites within the Arabidopsis Bay x Sha recombinant inbred line population. In this analysis, all loci controlling expression variation also affected the accumulation of the resulting metabolites. In addition, epistasis was detected more frequently for metabolic traits compared to transcript traits, even when both traits showed similar distributions. An analysis of candidate genes for QTL-controlling networks of transcripts and metabolites suggested that the controlling factors are a mix of enzymes and regulatory factors. This analysis showed that regulatory connections can feedback from metabolism to transcripts. Surprisingly, the most likely major regulator of both transcript level for nearly the entire pathway and aliphatic glucosinolate accumulation is variation in the last enzyme in the biosynthetic pathway, AOP2. This suggests that natural variation in transcripts may significantly impact phenotypic variation, but that natural variation in metabolites or their enzymatic loci can feed back to affect the transcripts.

  4. Blockage of the pyrimidine biosynthetic pathway affects riboflavin production in Ashbya gossypii.

    Science.gov (United States)

    Silva, Rui; Aguiar, Tatiana Q; Domingues, Lucília

    2015-01-10

    The Ashbya gossypii riboflavin biosynthetic pathway and its connection with the purine pathway have been well studied. However, the outcome of genetic alterations in the pyrimidine pathway on riboflavin production by A. gossypii had not yet been assessed. Here, we report that the blockage of the de novo pyrimidine biosynthetic pathway in the recently generated A. gossypii Agura3 uridine/uracil auxotrophic strain led to improved riboflavin production on standard agar-solidified complex medium. When extra uridine/uracil was supplied, the production of riboflavin by this auxotroph was repressed. High concentrations of uracil hampered this (and the parent) strain growth, whereas excess uridine favored the A. gossypii Agura3 growth. Considering that the riboflavin and the pyrimidine pathways share the same precursors and that riboflavin overproduction may be triggered by nutritional stress, we suggest that overproduction of riboflavin by the A. gossypii Agura3 may occur as an outcome of a nutritional stress response and/or of an increased availability in precursors for riboflavin biosynthesis, due to their reduced consumption by the pyrimidine pathway. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Enhancement of cordyceps polysaccharide production via biosynthetic pathway analysis in Hirsutella sinensis.

    Science.gov (United States)

    Lin, Shan; Liu, Zhi-Qiang; Baker, Peter James; Yi, Ming; Wu, Hui; Xu, Feng; Teng, Yi; Zheng, Yu-Guo

    2016-11-01

    The addition of various sulfates for enhanced cordyceps polysaccharide (CP) production in submerged cultivation of H. sinensis was investigated, and manganese sulfate was found the most effective. 2mM of manganese sulfate on 0day (d) was investigated as the optimal adding condition, and the CP production reached optimum with 5.33%, increasing by 93.3% compared with the control. Furthermore, the consumption of three main precursors of CP was studied over cultivation under two conditions. Intracellular mannose content decreased by 43.1% throughout 6days cultivation, which corresponded to CP accumulation rate sharply increased from 0 d to 6 d, and mannose was considered as the most preferred precursor for generating CP. Subsequently, mannose biosynthetic pathway was constructed and verified for the first time in H. sinensis, which constituted the important part of CP biosynthesis, and transcriptional levels of the biosynthetic genes were studied. Transcriptional level of gene cpsA was significantly up-regulated 5.35-fold and it was a key gene involved both in mannose and CP biosynthesis. This study demonstrated that manganese sulfate addition is an efficient and simple way to improve CP production. Transcriptional analysis based on biosynthetic pathway was helpful to find key genes and better understand CP biosynthesis. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Unravelling Protein-Protein Interaction Networks Linked to Aliphatic and Indole Glucosinolate Biosynthetic Pathways in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Sebastian J. Nintemann

    2017-11-01

    Full Text Available Within the cell, biosynthetic pathways are embedded in protein-protein interaction networks. In Arabidopsis, the biosynthetic pathways of aliphatic and indole glucosinolate defense compounds are well-characterized. However, little is known about the spatial orchestration of these enzymes and their interplay with the cellular environment. To address these aspects, we applied two complementary, untargeted approaches—split-ubiquitin yeast 2-hybrid and co-immunoprecipitation screens—to identify proteins interacting with CYP83A1 and CYP83B1, two homologous enzymes specific for aliphatic and indole glucosinolate biosynthesis, respectively. Our analyses reveal distinct functional networks with substantial interconnection among the identified interactors for both pathway-specific markers, and add to our knowledge about how biochemical pathways are connected to cellular processes. Specifically, a group of protein interactors involved in cell death and the hypersensitive response provides a potential link between the glucosinolate defense compounds and defense against biotrophic pathogens, mediated by protein-protein interactions.

  7. The immediate nucleotide precursor, guanosine triphosphate, in the riboflavin biosynthetic pathway

    International Nuclear Information System (INIS)

    Mitsuda, Hisateru; Nakajima, Kenji; Nadamoto, Tomonori

    1977-01-01

    In the present paper, the nucleotide precursor of riboflavin was investigated by experiments with labeled purines using non-growing cells of Eremothecium ashbyii. The added purines, at 10 -4 M, were effectively incorporated into riboflavin at an early stage of riboflavin biosynthesis under the experimental conditions. In particular, both labeled xanthine and labeled guanine were specifically transported to guanosine nucleotides, GMP, GDP, GDP-Mannose and GTP, in the course of the riboflavin biosynthesis. A comparison of specific activities of labeled guanosine nucleotides and labeled riboflavin indicated that the nucleotide precursor of riboflavin is guanosine triphosphate. From the results obtained, a biosynthetic pathway of riboflavin is proposed. (auth.)

  8. Genetic determination of the meso-diaminopimelate biosynthetic pathway of mycobacteria.

    Science.gov (United States)

    Cirillo, J D; Weisbrod, T R; Banerjee, A; Bloom, B R; Jacobs, W R

    1994-07-01

    The increasing incidence of multiple-drug-resistant mycobacterial infections indicates that the development of new methods for treatment of mycobacterial diseases should be a high priority. meso-Diaminopimelic acid (DAP), a key component of a highly immunogenic subunit of the mycobacterial peptidoglycan layer, has been implicated as a potential virulence factor. The mycobacterial DAP biosynthetic pathway could serve as a target for design of new antimycobacterial agents as well as the construction of in vivo selection systems. We have isolated the asd, dapA, dapB, dapD, and dapE genes involved in the DAP biosynthetic pathway of Mycobacterium bovis BCG. These genes were isolated by complementation of Escherichia coli mutations with an expression library of BCG DNA. Our analysis of these genes suggests that BCG may use more than one pathway for biosynthesis of DAP. The nucleotide sequence of the BCG dapB gene was determined. The activity of the product of this gene in Escherichia coli provided evidence that the gene may encode a novel bifunctional dihydrodipicolinate reductase and DAP dehydrogenase.

  9. Metabolic engineering to simultaneously activate anthocyanin and proanthocyanidin biosynthetic pathways in Nicotiana spp.

    Directory of Open Access Journals (Sweden)

    Sandra Fresquet-Corrales

    Full Text Available Proanthocyanidins (PAs, or condensed tannins, are powerful antioxidants that remove harmful free oxygen radicals from cells. To engineer the anthocyanin and proanthocyanidin biosynthetic pathways to de novo produce PAs in two Nicotiana species, we incorporated four transgenes to the plant chassis. We opted to perform a simultaneous transformation of the genes linked in a multigenic construct rather than classical breeding or retransformation approaches. We generated a GoldenBraid 2.0 multigenic construct containing two Antirrhinum majus transcription factors (AmRosea1 and AmDelila to upregulate the anthocyanin pathway in combination with two Medicago truncatula genes (MtLAR and MtANR to produce the enzymes that will derivate the biosynthetic pathway to PAs production. Transient and stable transformation of Nicotiana benthamiana and Nicotiana tabacum with the multigenic construct were respectively performed. Transient expression experiments in N. benthamiana showed the activation of the anthocyanin pathway producing a purple color in the agroinfiltrated leaves and also the effective production of 208.5 nmol (- catechin/g FW and 228.5 nmol (- epicatechin/g FW measured by the p-dimethylaminocinnamaldehyde (DMACA method. The integration capacity of the four transgenes, their respective expression levels and their heritability in the second generation were analyzed in stably transformed N. tabacum plants. DMACA and phoroglucinolysis/HPLC-MS analyses corroborated the activation of both pathways and the effective production of PAs in T0 and T1 transgenic tobacco plants up to a maximum of 3.48 mg/g DW. The possible biotechnological applications of the GB2.0 multigenic approach in forage legumes to produce "bloat-safe" plants and to improve the efficiency of conversion of plant protein into animal protein (ruminal protein bypass are discussed.

  10. Expression of carotenoid biosynthetic pathway genes and changes in carotenoids during ripening in tomato (Lycopersicon esculentum).

    Science.gov (United States)

    Namitha, Kanakapura Krishnamurthy; Archana, Surya Narayana; Negi, Pradeep Singh

    2011-04-01

    To study the expression pattern of carotenoid biosynthetic pathway genes, changes in their expression at different stages of maturity in tomato fruit (cv. Arka Ahuti) were investigated. The genes regulating carotenoid production were quantified by a dot blot method using a DIG (dioxigenin) labelling and detection kit. The results revealed that there was an increase in the levels of upstream genes of the carotenoid biosynthetic pathway such as 1-deoxy-d-xylulose-5-phosphate reductoisomerase (DXR), 4-hydroxy-3-methyl-but-2-enyl diphosphate reductase (Lyt B), phytoene synthase (PSY), phytoene desaturase (PDS) and ζ-carotene desaturase (ZDS) by 2-4 fold at the breaker stage as compared to leaf. The lycopene and β-carotene content was analyzed by HPLC at different stages of maturity. The lycopene (15.33 ± 0.24 mg per 100 g) and β-carotene (10.37 ± 0.46 mg per 100 g) content were found to be highest at 5 days post-breaker and 10 days post-breaker stage, respectively. The lycopene accumulation pattern also coincided with the color values at different stages of maturity. These studies may provide insight into devising gene-based strategies for enhancing carotenoid accumulation in tomato fruits.

  11. Enrichment of Bacteria From Eastern Mediterranean Sea Involved in Lignin Degradation via the Phenylacetyl-CoA Pathway

    Directory of Open Access Journals (Sweden)

    Hannah L. Woo

    2018-05-01

    Full Text Available The degradation of allochthonous terrestrial organic matter, such as recalcitrant lignin and hemicellulose from plants, occurs in the ocean. We hypothesize that bacteria instead of white-rot fungi, the model organisms of aerobic lignin degradation within terrestrial environments, are responsible for lignin degradation in the ocean due to the ocean’s oligotrophy and hypersalinity. Warm oxic seawater from the Eastern Mediterranean Sea was enriched on lignin in laboratory microcosms. Lignin mineralization rates by the lignin-adapted consortia improved after two sequential incubations. Shotgun metagenomic sequencing detected a higher abundance of aromatic compound degradation genes in response to lignin, particularly phenylacetyl-CoA, which may be an effective strategy for marine microbes in fluctuating oxygen concentrations. 16S rRNA gene amplicon sequencing detected a higher abundance of Gammaproteobacteria and Alphaproteobacteria bacteria such as taxonomic families Idiomarinaceae, Alcanivoraceae, and Alteromonadaceae in response to lignin. Meanwhile, fungal Ascomycetes and Basidiomycetes remained at very low abundance. Our findings demonstrate the significant potential of bacteria and microbes utilizing the phenylacetyl-CoA pathway to contribute to lignin degradation in the Eastern Mediterranean where environmental conditions are unfavorable for fungi. Exploring the diversity of bacterial lignin degraders may provide important enzymes for lignin conversion in industry. Enzymes may be key in breaking down high molecular weight lignin and enabling industry to use it as a low-cost and sustainable feedstock for biofuels or other higher-value products.

  12. Optimization of RT-PCR reactions in studies with genes of lignin biosynthetic route in Saccharum spontaneum

    Directory of Open Access Journals (Sweden)

    JUAN P.P. LLERENA

    Full Text Available ABSTRACT Saccharum spontaneum has been used for the development of energy cane a crop aimed to be used for the production of second-generation ethanol, or lignocellulosic ethanol. Lignin is a main challenge in the conversion of cell wall sugars into ethanol. In our studies to isolate the genes the lignin biosynthesis in S. spontaneum we have had great difficulty in RT-PCR reactions. Thus, we evaluated the effectiveness of different additives in the amplification of these genes. While COMT and CCoAOMT genes did not need any additives for other genes there was no amplification (HCT, F5H, 4CL and CCR or the yield was very low (CAD and C4H. The application of supplementary cDNA was enough to overcome the non-specificity and low yield for C4H and C3H, while the addition of 0.04% BSA + 2% formamide was effective to amplify 4CL, CCR, F5H and CCR. HCT was amplified only by addition of 0.04% BSA + 2% formamide + 0.1 M trehalose and amplification of PAL was possible with addition of 2% of DMSO. Besides optimization of expression assays, the results show that additives can act independently or synergistically.

  13. Enzymatic activities for lignin monomer intermediates highlight the biosynthetic pathway of syringyl monomers in Robinia pseudoacacia.

    Science.gov (United States)

    Shigeto, Jun; Ueda, Yukie; Sasaki, Shinya; Fujita, Koki; Tsutsumi, Yuji

    2017-01-01

    Most of the known 4-coumarate:coenzyme A ligase (4CL) isoforms lack CoA-ligation activity for sinapic acid. Therefore, there is some doubt as to whether sinapic acid contributes to sinapyl alcohol biosynthesis. In this study, we characterized the enzyme activity of a protein mixture extracted from the developing xylem of Robinia pseudoacacia. The crude protein mixture contained at least two 4CLs with sinapic acid 4-CoA ligation activity. The crude enzyme preparation displayed negligible sinapaldehyde dehydrogenase activity, but showed ferulic acid 5-hydroxylation activity and 5-hydroxyferulic acid O-methyltransferase activity; these activities were retained in the presence of competitive substrates (coniferaldehyde and 5-hydroxyconiferaldehyde, respectively). 5-Hydroxyferulic acid and sinapic acid accumulated in the developing xylem of R. pseudoacacia, suggesting, in part at least, sinapic acid is a sinapyl alcohol precursor in this species.

  14. Examination of triacylglycerol biosynthetic pathways via de novo transcriptomic and proteomic analyses in an unsequenced microalga.

    Directory of Open Access Journals (Sweden)

    Michael T Guarnieri

    Full Text Available Biofuels derived from algal lipids represent an opportunity to dramatically impact the global energy demand for transportation fuels. Systems biology analyses of oleaginous algae could greatly accelerate the commercialization of algal-derived biofuels by elucidating the key components involved in lipid productivity and leading to the initiation of hypothesis-driven strain-improvement strategies. However, higher-level systems biology analyses, such as transcriptomics and proteomics, are highly dependent upon available genomic sequence data, and the lack of these data has hindered the pursuit of such analyses for many oleaginous microalgae. In order to examine the triacylglycerol biosynthetic pathway in the unsequenced oleaginous microalga, Chlorella vulgaris, we have established a strategy with which to bypass the necessity for genomic sequence information by using the transcriptome as a guide. Our results indicate an upregulation of both fatty acid and triacylglycerol biosynthetic machinery under oil-accumulating conditions, and demonstrate the utility of a de novo assembled transcriptome as a search model for proteomic analysis of an unsequenced microalga.

  15. Secondary metabolism in Fusarium fujikuroi: strategies to unravel the function of biosynthetic pathways.

    Science.gov (United States)

    Janevska, Slavica; Tudzynski, Bettina

    2018-01-01

    The fungus Fusarium fujikuroi causes bakanae disease of rice due to its ability to produce the plant hormones, the gibberellins. The fungus is also known for producing harmful mycotoxins (e.g., fusaric acid and fusarins) and pigments (e.g., bikaverin and fusarubins). However, for a long time, most of these well-known products could not be linked to biosynthetic gene clusters. Recent genome sequencing has revealed altogether 47 putative gene clusters. Most of them were orphan clusters for which the encoded natural product(s) were unknown. In this review, we describe the current status of our research on identification and functional characterizations of novel secondary metabolite gene clusters. We present several examples where linking known metabolites to the respective biosynthetic genes has been achieved and describe recent strategies and methods to access new natural products, e.g., by genetic manipulation of pathway-specific or global transcritption factors. In addition, we demonstrate that deletion and over-expression of histone-modifying genes is a powerful tool to activate silent gene clusters and to discover their products.

  16. Genome sequence of Thermofilum pendens reveals an exceptional loss of biosynthetic pathways without genome reduction

    Energy Technology Data Exchange (ETDEWEB)

    Kyrpides, Nikos; Anderson, Iain; Rodriguez, Jason; Susanti, Dwi; Porat, Iris; Reich, Claudia; Ulrich, Luke E.; Elkins, James G.; Mavromatis, Kostas; Lykidis, Athanasios; Kim, Edwin; Thompson, Linda S.; Nolan, Matt; Land, Miriam; Copeland, Alex; Lapidus, Alla; Lucas, Susan; Detter, Chris; Zhulin, Igor B.; Olsen, Gary J.; Whitman, William; Mukhopadhyay, Biswarup; Bristow, James; Kyrpides, Nikos

    2008-01-01

    We report the complete genome of Thermofilum pendens, a deep-branching, hyperthermophilic member of the order Thermoproteales within the archaeal kingdom Crenarchaeota. T. pendens is a sulfur-dependent, anaerobic heterotroph isolated from a solfatara in Iceland. It is an extracellular commensal, requiring an extract of Thermoproteus tenax for growth, and the genome sequence reveals that biosynthetic pathways for purines, most amino acids, and most cofactors are absent. In fact T. pendens has fewer biosynthetic enzymes than obligate intracellular parasites, although it does not display other features common among obligate parasites and thus does not appear to be in the process of becoming a parasite. It appears that T. pendens has adapted to life in an environment rich in nutrients. T. pendens was known to utilize peptides as an energy source, but the genome reveals substantial ability to grow on carbohydrates. T. pendens is the first crenarchaeote and only the second archaeon found to have a transporter of the phosphotransferase system. In addition to fermentation, T. pendens may gain energy from sulfur reduction with hydrogen and formate as electron donors. It may also be capable of sulfur-independent growth on formate with formate hydrogenlyase. Additional novel features are the presence of a monomethylamine:corrinoid methyltransferase, the first time this enzyme has been found outside of Methanosarcinales, and a presenilin-related protein. Predicted highly expressed proteins do not include housekeeping genes, and instead include ABC transporters for carbohydrates and peptides, and CRISPR-associated proteins.

  17. Modulation of guanosine nucleotides biosynthetic pathways enhanced GDP-L-fucose production in recombinant Escherichia coli.

    Science.gov (United States)

    Lee, Won-Heong; Shin, So-Yeon; Kim, Myoung-Dong; Han, Nam Soo; Seo, Jin-Ho

    2012-03-01

    Guanosine 5'-triphosphate (GTP) is the key substrate for biosynthesis of guanosine 5'-diphosphate (GDP)-L-fucose. In this study, improvement of GDP-L-fucose production was attempted by manipulating the biosynthetic pathway for guanosine nucleotides in recombinant Escherichia coli-producing GDP-L-fucose. The effects of overexpression of inosine 5'-monophosphate (IMP) dehydrogenase, guanosine 5'-monophosphate (GMP) synthetase (GuaB and GuaA), GMP reductase (GuaC) and guanosine-inosine kinase (Gsk) on GDP-L-fucose production were investigated in a series of fed-batch fermentations. Among the enzymes tested, overexpression of Gsk led to a significant improvement of GDP-L-fucose production. Maximum GDP-L-fucose concentration of 305.5 ± 5.3 mg l(-1) was obtained in the pH-stat fed-batch fermentation of recombinant E. coli-overexpressing Gsk, which corresponds to a 58% enhancement in the GDP-L-fucose production compared with the control strain overexpressing GDP-L-fucose biosynthetic enzymes. Such an enhancement of GDP-L-fucose production could be due to the increase in the intracellular level of GMP.

  18. The Cremeomycin Biosynthetic Gene Cluster Encodes a Pathway for Diazo Formation.

    Science.gov (United States)

    Waldman, Abraham J; Pechersky, Yakov; Wang, Peng; Wang, Jennifer X; Balskus, Emily P

    2015-10-12

    Diazo groups are found in a range of natural products that possess potent biological activities. Despite longstanding interest in these metabolites, diazo group biosynthesis is not well understood, in part because of difficulties in identifying specific genes linked to diazo formation. Here we describe the discovery of the gene cluster that produces the o-diazoquinone natural product cremeomycin and its heterologous expression in Streptomyces lividans. We used stable isotope feeding experiments and in vitro characterization of biosynthetic enzymes to decipher the order of events in this pathway and establish that diazo construction involves late-stage N-N bond formation. This work represents the first successful production of a diazo-containing metabolite in a heterologous host, experimentally linking a set of genes with diazo formation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Leveraging microbial biosynthetic pathways for the generation of 'drop-in' biofuels.

    Science.gov (United States)

    Zargar, Amin; Bailey, Constance B; Haushalter, Robert W; Eiben, Christopher B; Katz, Leonard; Keasling, Jay D

    2017-06-01

    Advances in retooling microorganisms have enabled bioproduction of 'drop-in' biofuels, fuels that are compatible with existing spark-ignition, compression-ignition, and gas-turbine engines. As the majority of petroleum consumption in the United States consists of gasoline (47%), diesel fuel and heating oil (21%), and jet fuel (8%), 'drop-in' biofuels that replace these petrochemical sources are particularly attractive. In this review, we discuss the application of aldehyde decarbonylases to produce gasoline substitutes from fatty acid products, a recently crystallized reductase that could hydrogenate jet fuel precursors from terpene synthases, and the exquisite control of polyketide synthases to produce biofuels with desired physical properties (e.g., lower freezing points). With our increased understanding of biosynthetic logic of metabolic pathways, we discuss the unique advantages of fatty acid, terpene, and polyketide synthases for the production of bio-based gasoline, diesel and jet fuel. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Sex pheromone biosynthetic pathways are conserved between moths and the butterfly Bicyclus anynana

    Science.gov (United States)

    Liénard, Marjorie A; Wang, Hong-Lei; Lassance, Jean-Marc; Löfstedt, Christer

    2014-01-01

    Although phylogenetically nested within the moths, butterflies have diverged extensively in a number of life history traits. Whereas moths rely greatly on chemical signals, visual advertisement is the hallmark of mate finding in butterflies. In the context of courtship, however, male chemical signals are widespread in both groups although they likely have multiple evolutionary origins. Here, we report that in males of the butterfly Bicyclus anynana, courtship scents are produced de novo via biosynthetic pathways shared with females of many moth species. We show that two of the pheromone components that play a major role in mate choice, namely the (Z)-9-tetradecenol and hexadecanal, are produced through the activity of a fatty acyl Δ11-desaturase and two specialized alcohol-forming fatty acyl reductases. Our study provides the first evidence of conservation and sharing of ancestral genetic modules for the production of FA-derived pheromones over a long evolutionary timeframe thereby reconciling mate communication in moths and butterflies. PMID:24862548

  1. Transcriptional repressor role of PocR on the 1,3-propanediol biosynthetic pathway by Lactobacillus panis PM1.

    Science.gov (United States)

    Kang, Tae Sun; Korber, Darren R; Tanaka, Takuji

    2014-06-01

    The regulatory role of a transcriptional regulator (PocR) in the 1,3-propanediol biosynthetic pathway of Lactobacillus panis PM1 contributes to the optimization of 1,3-propanediol production by this strain, which potentially will lead to 1,3-propanediol manufacturing efficiencies. Lactobacillus panis PM1 can utilize a 1,3-propanediol (1,3-PDO) biosynthetic pathway, consisting of diol dehydratase (PduCDE) and 1,3-PDO dehydrogenase, as a NADH recycling system, to survive under various environmental conditions. In this study, we identified a key transcriptional repressor (PocR) which was annotated as a transcriptional factor of AraC family as part of the 1,3-PDO biosynthetic pathway of L. panis PM1. The over-expression of the PocR gene resulted in the significant repression (81 %) of pduC (PduCDE large subunit) transcription, and subsequently, the decreased activity of PduCDE by 22 %. As a result of the regulation of PduCDE, production of both 3-hydroxypropionaldehyde and 1,3-PDO in the PocR over-expressing strain were significantly decreased by 40 % relative to the control strain. These results clearly demonstrate the transcriptional repressor role of PocR in the 1,3-PDO biosynthetic pathway.

  2. Engineering Plant Biomass Lignin Content and Composition for Biofuels and Bioproducts

    Directory of Open Access Journals (Sweden)

    Cassie Marie Welker

    2015-07-01

    Full Text Available Lignin is an aromatic biopolymer involved in providing structural support to plant cell walls. Compared to the other cell wall polymers, i.e., cellulose and hemicelluloses, lignin has been considered a hindrance in cellulosic bioethanol production due to the complexity involved in its separation from other polymers of various biomass feedstocks. Nevertheless, lignin is a potential source of valuable aromatic chemical compounds and upgradable building blocks. Though the biosynthetic pathway of lignin has been elucidated in great detail, the random nature of the polymerization (free radical coupling process poses challenges for its depolymerization into valuable bioproducts. The absence of specific methodologies for lignin degradation represents an important opportunity for research and development. This review highlights research development in lignin biosynthesis, lignin genetic engineering and different biological and chemical means of depolymerization used to convert lignin into biofuels and bioproducts.

  3. Metabolic engineering of the omega-3 long chain polyunsaturated fatty acid biosynthetic pathway into transgenic plants.

    Science.gov (United States)

    Ruiz-López, Noemi; Sayanova, Olga; Napier, Johnathan A; Haslam, Richard P

    2012-04-01

    Omega-3 (ω-3) very long chain polyunsaturated fatty acids (VLC-PUFAs) such as eicosapentaenoic acid (EPA; 20:5 Δ5,8,11,14,17) and docosahexaenoic acid (DHA; 22:6 Δ4,7,10,13,16,19) have been shown to have significant roles in human health. Currently the primary dietary source of these fatty acids are marine fish; however, the increasing demand for fish and fish oil (in particular the expansion of the aquaculture industry) is placing enormous pressure on diminishing marine stocks. Such overfishing and concerns related to pollution in the marine environment have directed research towards the development of a viable alternative sustainable source of VLC-PUFAs. As a result, the last decade has seen many genes encoding the primary VLC-PUFA biosynthetic activities identified and characterized. This has allowed the reconstitution of the VLC-PUFA biosynthetic pathway in oilseed crops, producing transgenic plants engineered to accumulate ω-3 VLC-PUFAs at levels approaching those found in native marine organisms. Moreover, as a result of these engineering activities, knowledge of the fundamental processes surrounding acyl exchange and lipid remodelling has progressed. The application of new technologies, for example lipidomics and next-generation sequencing, is providing a better understanding of seed oil biosynthesis and opportunities for increasing the production of unusual fatty acids. Certainly, it is now possible to modify the composition of plant oils successfully, and, in this review, the most recent developments in this field and the challenges of producing VLC-PUFAs in the seed oil of higher plants will be described.

  4. Biosynthetic pathway of the phytohormone auxin in insects and screening of its inhibitors.

    Science.gov (United States)

    Suzuki, Hiroyoshi; Yokokura, Junpei; Ito, Tsukasa; Arai, Ryoma; Yokoyama, Chiaki; Toshima, Hiroaki; Nagata, Shinji; Asami, Tadao; Suzuki, Yoshihito

    2014-10-01

    Insect galls are abnormal plant tissues induced by galling insects. The galls are used for food and habitation, and the phytohormone auxin, produced by the insects, may be involved in their formation. We found that the silkworm, a non-galling insect, also produces an active form of auxin, indole-3-acetic acid (IAA), by de novo synthesis from tryptophan (Trp). A detailed metabolic analysis of IAA using IAA synthetic enzymes from silkworms indicated an IAA biosynthetic pathway composed of a three-step conversion: Trp → indole-3-acetaldoxime → indole-3-acetaldehyde (IAAld) → IAA, of which the first step is limiting IAA production. This pathway was shown to also operate in gall-inducing sawfly. Screening of a chemical library identified two compounds that showed strong inhibitory activities on the conversion step IAAld → IAA. The inhibitors can be efficiently used to demonstrate the importance of insect-synthesized auxin in gall formation in the future. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Evolutionary origins and functions of the carotenoid biosynthetic pathway in marine diatoms.

    Directory of Open Access Journals (Sweden)

    Sacha Coesel

    Full Text Available Carotenoids are produced by all photosynthetic organisms, where they play essential roles in light harvesting and photoprotection. The carotenoid biosynthetic pathway of diatoms is largely unstudied, but is of particular interest because these organisms have a very different evolutionary history with respect to the Plantae and are thought to be derived from an ancient secondary endosymbiosis between heterotrophic and autotrophic eukaryotes. Furthermore, diatoms have an additional xanthophyll-based cycle for dissipating excess light energy with respect to green algae and higher plants. To explore the origins and functions of the carotenoid pathway in diatoms we searched for genes encoding pathway components in the recently completed genome sequences of two marine diatoms. Consistent with the supplemental xanthophyll cycle in diatoms, we found more copies of the genes encoding violaxanthin de-epoxidase (VDE and zeaxanthin epoxidase (ZEP enzymes compared with other photosynthetic eukaryotes. However, the similarity of these enzymes with those of higher plants indicates that they had very probably diversified before the secondary endosymbiosis had occurred, implying that VDE and ZEP represent early eukaryotic innovations in the Plantae. Consequently, the diatom chromist lineage likely obtained all paralogues of ZEP and VDE genes during the process of secondary endosymbiosis by gene transfer from the nucleus of the algal endosymbiont to the host nucleus. Furthermore, the presence of a ZEP gene in Tetrahymena thermophila provides the first evidence for a secondary plastid gene encoded in a heterotrophic ciliate, providing support for the chromalveolate hypothesis. Protein domain structures and expression analyses in the pennate diatom Phaeodactylum tricornutum indicate diverse roles for the different ZEP and VDE isoforms and demonstrate that they are differentially regulated by light. These studies therefore reveal the ancient origins of several

  6. Evolutionary origins and functions of the carotenoid biosynthetic pathway in marine diatoms.

    Science.gov (United States)

    Coesel, Sacha; Oborník, Miroslav; Varela, Joao; Falciatore, Angela; Bowler, Chris

    2008-08-06

    Carotenoids are produced by all photosynthetic organisms, where they play essential roles in light harvesting and photoprotection. The carotenoid biosynthetic pathway of diatoms is largely unstudied, but is of particular interest because these organisms have a very different evolutionary history with respect to the Plantae and are thought to be derived from an ancient secondary endosymbiosis between heterotrophic and autotrophic eukaryotes. Furthermore, diatoms have an additional xanthophyll-based cycle for dissipating excess light energy with respect to green algae and higher plants. To explore the origins and functions of the carotenoid pathway in diatoms we searched for genes encoding pathway components in the recently completed genome sequences of two marine diatoms. Consistent with the supplemental xanthophyll cycle in diatoms, we found more copies of the genes encoding violaxanthin de-epoxidase (VDE) and zeaxanthin epoxidase (ZEP) enzymes compared with other photosynthetic eukaryotes. However, the similarity of these enzymes with those of higher plants indicates that they had very probably diversified before the secondary endosymbiosis had occurred, implying that VDE and ZEP represent early eukaryotic innovations in the Plantae. Consequently, the diatom chromist lineage likely obtained all paralogues of ZEP and VDE genes during the process of secondary endosymbiosis by gene transfer from the nucleus of the algal endosymbiont to the host nucleus. Furthermore, the presence of a ZEP gene in Tetrahymena thermophila provides the first evidence for a secondary plastid gene encoded in a heterotrophic ciliate, providing support for the chromalveolate hypothesis. Protein domain structures and expression analyses in the pennate diatom Phaeodactylum tricornutum indicate diverse roles for the different ZEP and VDE isoforms and demonstrate that they are differentially regulated by light. These studies therefore reveal the ancient origins of several components of the

  7. Spliced X-box binding protein 1 couples the unfolded protein response to hexosamine biosynthetic pathway.

    Science.gov (United States)

    Wang, Zhao V; Deng, Yingfeng; Gao, Ningguo; Pedrozo, Zully; Li, Dan L; Morales, Cyndi R; Criollo, Alfredo; Luo, Xiang; Tan, Wei; Jiang, Nan; Lehrman, Mark A; Rothermel, Beverly A; Lee, Ann-Hwee; Lavandero, Sergio; Mammen, Pradeep P A; Ferdous, Anwarul; Gillette, Thomas G; Scherer, Philipp E; Hill, Joseph A

    2014-03-13

    The hexosamine biosynthetic pathway (HBP) generates uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) for glycan synthesis and O-linked GlcNAc (O-GlcNAc) protein modifications. Despite the established role of the HBP in metabolism and multiple diseases, regulation of the HBP remains largely undefined. Here, we show that spliced X-box binding protein 1 (Xbp1s), the most conserved signal transducer of the unfolded protein response (UPR), is a direct transcriptional activator of the HBP. We demonstrate that the UPR triggers HBP activation via Xbp1s-dependent transcription of genes coding for key, rate-limiting enzymes. We further establish that this previously unrecognized UPR-HBP axis is triggered in a variety of stress conditions. Finally, we demonstrate a physiologic role for the UPR-HBP axis by showing that acute stimulation of Xbp1s in heart by ischemia/reperfusion confers robust cardioprotection in part through induction of the HBP. Collectively, these studies reveal that Xbp1s couples the UPR to the HBP to protect cells under stress. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Molecular and Biochemical Analysis of Chalcone Synthase from Freesia hybrid in flavonoid biosynthetic pathway.

    Directory of Open Access Journals (Sweden)

    Wei Sun

    Full Text Available Chalcone synthase (CHS catalyzes the first committed step in the flavonoid biosynthetic pathway. In this study, the cDNA (FhCHS1 encoding CHS from Freesia hybrida was successfully isolated and analyzed. Multiple sequence alignments showed that both the conserved CHS active site residues and CHS signature sequence were found in the deduced amino acid sequence of FhCHS1. Meanwhile, crystallographic analysis revealed that protein structure of FhCHS1 is highly similar to that of alfalfa CHS2, and the biochemical analysis results indicated that it has an enzymatic role in naringenin biosynthesis. Moreover, quantitative real-time PCR was performed to detect the transcript levels of FhCHS1 in flowers and different tissues, and patterns of FhCHS1 expression in flowers showed significant correlation to the accumulation patterns of anthocyanin during flower development. To further characterize the functionality of FhCHS1, its ectopic expression in Arabidopsis thaliana tt4 mutants and Petunia hybrida was performed. The results showed that overexpression of FhCHS1 in tt4 mutants fully restored the pigmentation phenotype of the seed coats, cotyledons and hypocotyls, while transgenic petunia expressing FhCHS1 showed flower color alteration from white to pink. In summary, these results suggest that FhCHS1 plays an essential role in the biosynthesis of flavonoid in Freesia hybrida and may be used to modify the components of flavonoids in other plants.

  9. Gene expression in the lignin biosynthesis pathway during soybean seed development.

    Science.gov (United States)

    Baldoni, A; Von Pinho, E V R; Fernandes, J S; Abreu, V M; Carvalho, M L M

    2013-02-28

    The study of gene expression in plants is fundamental, and understanding the molecular mechanisms involved in important biological processes, such as biochemical pathways or signaling that are used or manipulated in improvement programs, are key for the production of high-quality soybean seeds. Reports related to gene expression of lignin in seeds are scarce in the literature. We studied the expression of the phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase, 4-hydroxycinnamate 3-hydroxylase, and cinnamyl alcohol dehydrogenase genes involved in lignin biosynthesis during the development of soybean (Glycine max L. Merrill) seeds. As the endogenous control, the eukaryotic elongation factor 1-beta gene was used in two biological replicates performed in triplicate. Relative quantitative expression of these genes during the R4, R5, R6, and R7 development stages was analyzed. Real-time polymerase chain reaction was used for the gene expression study. The analyses were carried out in an ABI PRISM 7500 thermocycler using the comparative Ct method and SYBR Green to detect amplification. The seed samples at the R4 stage were chosen as calibrators. Increased expression of the cinnamate-4-hydroxylase and PAL genes occurred in soybean seeds at the R5 and R6 development stages. The cinnamyl alcohol dehydrogenase gene was expressed during the final development phases of soybean seeds. In low-lignin soybean cultivars, the higher expression of the PAL gene occurs at development stages R6 and R7. Activation of the genes involved in the lignin biosynthesis pathway occurs at the beginning of soybean seed development.

  10. A R2R3-MYB transcription factor from Epimedium sagittatum regulates the flavonoid biosynthetic pathway.

    Directory of Open Access Journals (Sweden)

    Wenjun Huang

    Full Text Available Herba epimedii (Epimedium, a traditional Chinese medicine, has been widely used as a kidney tonic and antirheumatic medicine for thousands of years. The bioactive components in herba epimedii are mainly prenylated flavonol glycosides, end-products of the flavonoid pathway. Epimedium species are also used as garden plants due to the colorful flowers and leaves. Many R2R3-MYB transcription factors (TFs have been identified to regulate the flavonoid and anthocyanin biosynthetic pathways. However, little is known about the R2R3-MYB TFs involved in regulation of the flavonoid pathway in Epimedium. Here, we reported the isolation and functional characterization of the first R2R3-MYB TF (EsMYBA1 from Epimedium sagittatum (Sieb. Et Zucc. Maxim. Conserved domains and phylogenetic analysis showed that EsMYBA1 belonged to the subgroup 6 clade (anthocyanin-related MYB clade of R2R3-MYB family, which includes Arabidopsis AtPAP1, apple MdMYB10 and legume MtLAP1. EsMYBA1 was preferentially expressed in leaves, especially in red leaves that contain higher content of anthocyanin. Alternative splicing of EsMYBA1 resulted in three transcripts and two of them encoded a MYB-related protein. Yeast two-hybrid and transient luciferase expression assay showed that EsMYBA1 can interact with several bHLH regulators of the flavonoid pathway and activate the promoters of dihydroflavonol 4-reductase (DFR and anthocyanidin synthase (ANS. In both transgenic tobacco and Arabidopsis, overexpression of EsMYBA1 induced strong anthocyanin accumulation in reproductive and/or vegetative tissues via up-regulation of the main flavonoid-related genes. Furthermore, transient expression of EsMYBA1 in E. sagittatum leaves by Agrobacterium infiltration also induced anthocyanin accumulation in the wounded area. This first functional characterization of R2R3-MYB TFs in Epimedium species will promote further studies of the flavonoid biosynthesis and regulation in medicinal plants.

  11. A R2R3-MYB transcription factor from Epimedium sagittatum regulates the flavonoid biosynthetic pathway.

    Science.gov (United States)

    Huang, Wenjun; Sun, Wei; Lv, Haiyan; Luo, Ming; Zeng, Shaohua; Pattanaik, Sitakanta; Yuan, Ling; Wang, Ying

    2013-01-01

    Herba epimedii (Epimedium), a traditional Chinese medicine, has been widely used as a kidney tonic and antirheumatic medicine for thousands of years. The bioactive components in herba epimedii are mainly prenylated flavonol glycosides, end-products of the flavonoid pathway. Epimedium species are also used as garden plants due to the colorful flowers and leaves. Many R2R3-MYB transcription factors (TFs) have been identified to regulate the flavonoid and anthocyanin biosynthetic pathways. However, little is known about the R2R3-MYB TFs involved in regulation of the flavonoid pathway in Epimedium. Here, we reported the isolation and functional characterization of the first R2R3-MYB TF (EsMYBA1) from Epimedium sagittatum (Sieb. Et Zucc.) Maxim. Conserved domains and phylogenetic analysis showed that EsMYBA1 belonged to the subgroup 6 clade (anthocyanin-related MYB clade) of R2R3-MYB family, which includes Arabidopsis AtPAP1, apple MdMYB10 and legume MtLAP1. EsMYBA1 was preferentially expressed in leaves, especially in red leaves that contain higher content of anthocyanin. Alternative splicing of EsMYBA1 resulted in three transcripts and two of them encoded a MYB-related protein. Yeast two-hybrid and transient luciferase expression assay showed that EsMYBA1 can interact with several bHLH regulators of the flavonoid pathway and activate the promoters of dihydroflavonol 4-reductase (DFR) and anthocyanidin synthase (ANS). In both transgenic tobacco and Arabidopsis, overexpression of EsMYBA1 induced strong anthocyanin accumulation in reproductive and/or vegetative tissues via up-regulation of the main flavonoid-related genes. Furthermore, transient expression of EsMYBA1 in E. sagittatum leaves by Agrobacterium infiltration also induced anthocyanin accumulation in the wounded area. This first functional characterization of R2R3-MYB TFs in Epimedium species will promote further studies of the flavonoid biosynthesis and regulation in medicinal plants.

  12. The hedgehog pathway gene shifted functions together with the hmgcr-dependent isoprenoid biosynthetic pathway to orchestrate germ cell migration.

    Directory of Open Access Journals (Sweden)

    Girish Deshpande

    Full Text Available The Drosophila embryonic gonad is assembled from two distinct cell types, the Primordial Germ Cells (PGCs and the Somatic Gonadal Precursor cells (SGPs. The PGCs form at the posterior of blastoderm stage embryos and are subsequently carried inside the embryo during gastrulation. To reach the SGPs, the PGCs must traverse the midgut wall and then migrate through the mesoderm. A combination of local repulsive cues and attractive signals emanating from the SGPs guide migration. We have investigated the role of the hedgehog (hh pathway gene shifted (shf in directing PGC migration. shf encodes a secreted protein that facilitates the long distance transmission of Hh through the proteoglycan matrix after it is released from basolateral membranes of Hh expressing cells in the wing imaginal disc. shf is expressed in the gonadal mesoderm, and loss- and gain-of-function experiments demonstrate that it is required for PGC migration. Previous studies have established that the hmgcr-dependent isoprenoid biosynthetic pathway plays a pivotal role in generating the PGC attractant both by the SGPs and by other tissues when hmgcr is ectopically expressed. We show that production of this PGC attractant depends upon shf as well as a second hh pathway gene gγ1. Further linking the PGC attractant to Hh, we present evidence indicating that ectopic expression of hmgcr in the nervous system promotes the release/transmission of the Hh ligand from these cells into and through the underlying mesodermal cell layer, where Hh can contact migrating PGCs. Finally, potentiation of Hh by hmgcr appears to depend upon cholesterol modification.

  13. Functional Characterization of a Novel R2R3-MYB Transcription Factor Modulating the Flavonoid Biosynthetic Pathway from Epimedium sagittatum

    Directory of Open Access Journals (Sweden)

    Wenjun Huang

    2017-07-01

    Full Text Available Epimedium species have been widely used both as traditional Chinese medicinal plants and ornamental perennials. Both flavonols, acting as the major bioactive components (BCs and anthocyanins, predominantly contributing to the color diversity of Epimedium flowers belong to different classes of flavonoids. It is well-acknowledged that flavonoid biosynthetic pathway is predominantly regulated by R2R3-MYB transcription factor (TF as well as bHLH TF and WD40 protein at the transcriptional level. MYB TFs specifically regulating anthocyanin or flavonol biosynthetic pathway have been already isolated and functionally characterized from Epimedium sagittatum, but a R2R3-MYB TF involved in regulating both these two pathways has not been functionally characterized to date in Epimedium plants. In this study, we report the functional characterization of EsMYB9, a R2R3-MYB TF previously isolated from E. sagittatum. The previous study indicated that EsMYB9 belongs to a small subfamily of R2R3-MYB TFs containing grape VvMYB5a and VvMYB5b TFs, which regulate flavonoid biosynthetic pathway. The present studies show that overexpression of EsMYB9 in tobacco leads to increased transcript levels of flavonoid pathway genes and increased contents of anthocyanins and flavonols. Yeast two-hybrid assay indicates that the C-terminal region of EsMYB9 contributes to the autoactivation activity, and EsMYB9 interacts with EsTT8 or AtTT8 bHLH regulator. Transient reporter assay shows that EsMYB9 slightly activates the expression of EsCHS (chalcone synthase promoter in transiently transformed leaves of Nicotiana benthamiana, but the addition of AtTT8 or EsTT8 bHLH regulator strongly enhances the transcriptional activation of EsMYB9 against five promoters of the flavonoid pathway genes except EsFLS (flavonol synthase. In addition, co-transformation of EsMYB9 and EsTT8 in transiently transfected tobacco leaves strongly induces the expressions of flavonoid biosynthetic genes. The

  14. Coordinated transcriptional regulation of two key genes in the lignin branch pathway--CAD and CCR--is mediated through MYB- binding sites.

    Science.gov (United States)

    Rahantamalala, Anjanirina; Rech, Philippe; Martinez, Yves; Chaubet-Gigot, Nicole; Grima-Pettenati, Jacqueline; Pacquit, Valérie

    2010-06-28

    importance of MYB cis-elements in the transcriptional regulation of two genes of the lignin-specific pathway and support the hypothesis that MYB elements serve as a common means for the coordinated regulation of genes in the entire lignin biosynthetic pathway.

  15. Connecting lignin-degradation pathway with pretreatment inhibitor sensitivity of Cupriavidus necator

    Directory of Open Access Journals (Sweden)

    Wei eWang

    2014-05-01

    Full Text Available To produce lignocellulosic biofuels economically, the complete release of monomers from the plant cell wall components, cellulose, hemicellulose and lignin, through pretreatment and hydrolysis (both enzymatic and chemical, and the efficient utilization of these monomers as carbon sources, is crucial. In addition, the identification and development of robust microbial biofuel production strains that can tolerate the toxic compounds generated during pretreatment and hydrolysis is also essential. In this work, Cupriavidus necator was selected due to its capabilities for utilizing lignin monomers and producing polyhydroxylbutyrate (PHB, a bioplastic as well as an advanced biofuel intermediate. We characterized the growth kinetics of C. necator in pretreated corn stover slurry as well as individually in the presence of 11 potentially toxic compounds in the saccharified slurry. We found that C. necator was sensitive to the saccharified slurry produced from dilute acid pretreated corn stover. Five out of 11 compounds within the slurry were characterized as toxic to C. necator, namely ammonium acetate, furfural, hydroxymethylfurfural (HMF, benzoic acid, and p-coumaric acid. Aldehydes (e.g., furfural and HMF were more toxic than the acetate and the lignin degradation products benzoic acid and p-coumaric acid; furfural was identified as the most toxic compound. Although toxic to C. necator at high concentration, ammonium acetate, benzoic acid, and p-coumaric acid could be utilized by C. necator with a stimulating effect on C. necator growth. Consequently, the lignin degradation pathway of C. necator was reconstructed based on genomic information and literature. The efficient conversion of intermediate catechol to downstream products of cis,cis-muconate or 2-hydroxymuconate-6-semialdehyde may help improve the robustness of C. necator to benzoic acid and p-coumaric acid as well as improve PHB productivity.

  16. Connecting Lignin-Degradation Pathway with Pre-Treatment Inhibitor Sensitivity of Cupriavidus necator

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Yang, S. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hunsinger, G. B. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Pienkos, P. T. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Johnson, D. K. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2014-05-27

    In order to produce lignocellulosic biofuels economically, the complete release of monomers from the plant cell wall components, cellulose, hemicellulose, and lignin, through pre-treatment and hydrolysis (both enzymatic and chemical), and the efficient utilization of these monomers as carbon sources, is crucial. In addition, the identification and development of robust microbial biofuel production strains that can tolerate the toxic compounds generated during pre-treatment and hydrolysis is also essential. In this work, Cupriavidus necator was selected due to its capabilities for utilizing lignin monomers and producing polyhydroxylbutyrate (PHB), a bioplastic as well as an advanced biofuel intermediate. We characterized the growth kinetics of C. necator in pre-treated corn stover slurry as well as individually in the pre-sence of 11 potentially toxic compounds in the saccharified slurry. We found that C. necator was sensitive to the saccharified slurry produced from dilute acid pre-treated corn stover. Five out of 11 compounds within the slurry were characterized as toxic to C. necator, namely ammonium acetate, furfural, hydroxymethylfurfural (HMF), benzoic acid, and p-coumaric acid. Aldehydes (e.g., furfural and HMF) were more toxic than the acetate and the lignin degradation products benzoic acid and p-coumaric acid; furfural was identified as the most toxic compound. Although toxic to C. necator at high concentration, ammonium acetate, benzoic acid, and p-coumaric acid could be utilized by C. necator with a stimulating effect on C. necator growth. Consequently, the lignin degradation pathway of C. necator was reconstructed based on genomic information and literature. The efficient conversion of intermediate catechol to downstream products of cis,cis-muconate or 2-hydroxymuconate-6-semialdehyde may help improve the robustness of C. necator to benzoic acid and p-coumaric acid as well as improve PHB productivity.

  17. Transcriptome and metabolome analysis of Ferula gummosa Boiss. to reveal major biosynthetic pathways of galbanum compounds.

    Science.gov (United States)

    Sobhani Najafabadi, Ahmad; Naghavi, Mohammad Reza; Farahmand, Hamid; Abbasi, Alireza

    2017-11-01

    Ferula gummosa Boiss. is an industrial and pharmaceutical plant that has been highly recognized for its valuable oleo-gum-resin, namely galbanum. Despite the fabulous value of galbanum, very little information on the genetic and biochemical mechanisms of its production existed. In the present study, the oleo-gum-resin and four organs (root, flower, stem, and leaf) of F. gummosa were assessed in terms of metabolic compositions and the expression of genes involved in their biosynthetic pathways. Results showed that the most accumulation of resin and essential oils were occurred in the roots (13.99 mg/g) and flowers (6.01 mg/g), respectively. While the most dominant compound of the resin was β-amyrin from triterpenes, the most abundant compounds of the essential oils were α-pinene and β-pinene from monoterpenes and α-eudesmol and germacrene-D from sesquiterpenes. Transcriptome analysis was performed by RNA sequencing (RNA-seq) for the plant roots and flowers. Differential gene expression analysis showed that 1172 unigenes were differential between two organs that 934 (79.6%) of them were up-regulated in the flowers and 238 (20.4%) unigenes were up-regulated in the roots (FDR ≤0.001). The most important up-regulated unigenes in the roots were involved in the biosynthesis of the major components of galbanum, including myrcene, germacrene-D, α-terpineol, and β-amyrin. The results obtained by RNA-Seq were confirmed by qPCR. These analyses showed that different organs of F. gummosa are involved in the production of oleo-gum-resin, but the roots are more active than other organs in terms of the biosynthesis of triterpenes and some mono- and sesquiterpenes. This study provides rich molecular and biochemical resources for further studies on molecular genetics and functional genomics of oleo-gum-resin production in F. gummosa.

  18. Regulation of the Omega-3 Fatty Acid Biosynthetic Pathway in Atlantic Salmon Hepatocytes.

    Directory of Open Access Journals (Sweden)

    Marte Avranden Kjær

    Full Text Available Limited availability of the n-3 fatty acids EPA and DHA have led to an interest in better understanding of the n-3 biosynthetic pathway and its regulation. The biosynthesis of alpha-linolenic acid to EPA and DHA involves several complex reaction steps including desaturation-, elongation- and peroxisomal beta-oxidation enzymes. The aims of the present experiments were to gain more knowledge on how this biosynthesis is regulated over time by different doses and fatty acid combinations. Hepatocytes isolated from salmon were incubated with various levels and combinations of oleic acid, EPA and DHA. Oleic acid led to a higher expression of the Δ6 fatty acid desaturase (fad genes Δ6fad_a, Δ6fad_b, Δ6fad_c and the elongase genes elovl2 compared with cells cultured in medium enriched with DHA. Further, the study showed rhythmic variations in expression over time. Levels were reached where a further increase in specific fatty acids given to the cells not stimulated the conversion further. The gene expression of Δ6fad_a_and Δ6fad_b responded similar to fatty acid treatment, suggesting a co-regulation of these genes, whereas Δ5fad and Δ6fad_c showed a different regulation pattern. EPA and DHA induced different gene expression patterns, especially of Δ6fad_a. Addition of radiolabelled alpha-linolenic acid to the hepatocytes confirmed a higher degree of elongation and desaturation in cells treated with oleic acid compared to cells treated with DHA. This study suggests a complex regulation of the conversion process of n-3 fatty acids. Several factors, such as that the various gene copies are differently regulated, the gene expression show rhythmic variations and gene expression only affected to a certain level, determines when you get the maximum conversion of the beneficial n-3 fatty acids.

  19. Production of Odd-Carbon Dicarboxylic Acids in Escherichia coli Using an Engineered Biotin-Fatty Acid Biosynthetic Pathway.

    Science.gov (United States)

    Haushalter, Robert W; Phelan, Ryan M; Hoh, Kristina M; Su, Cindy; Wang, George; Baidoo, Edward E K; Keasling, Jay D

    2017-04-05

    Dicarboxylic acids are commodity chemicals used in the production of plastics, polyesters, nylons, fragrances, and medications. Bio-based routes to dicarboxylic acids are gaining attention due to environmental concerns about petroleum-based production of these compounds. Some industrial applications require dicarboxylic acids with specific carbon chain lengths, including odd-carbon species. Biosynthetic pathways involving cytochrome P450-catalyzed oxidation of fatty acids in yeast and bacteria have been reported, but these systems produce almost exclusively even-carbon species. Here we report a novel pathway to odd-carbon dicarboxylic acids directly from glucose in Escherichia coli by employing an engineered pathway combining enzymes from biotin and fatty acid synthesis. Optimization of the pathway will lead to industrial strains for the production of valuable odd-carbon diacids.

  20. Effect of terbinafine on the biosynthetic pathway of isoprenoid compounds in carrot suspension cultured cells.

    Science.gov (United States)

    Miras-Moreno, Begoña; Almagro, Lorena; Pedreño, María Angeles; Sabater-Jara, Ana Belén

    2018-04-21

    Terbinafine induced a significant increase of squalene production. Terbinafine increased the expression levels of squalene synthase. Cyclodextrins did not work as elicitors due to the gene expression levels obtained. Plant sterols are essential components of membrane lipids, which contributing to their fluidity and permeability. Besides their cholesterol-lowering properties, they also have anti-inflammatory, antidiabetic and anticancer activities. Squalene, which is phytosterol precursor, is widely used in medicine, foods and cosmetics due to its anti-tumor, antioxidant and anti-aging activities. Nowadays, vegetable oils constitute the main sources of phytosterols and squalene, but their isolation and purification involve complex extraction protocols and high costs. In this work, Daucus carota cell cultures were used to evaluate the effect of cyclodextrins and terbinafine on the production and accumulation of squalene and phytosterols as well as the expression levels of squalene synthase and cycloartenol synthase genes. D. carota cell cultures were able to produce high levels of extracellular being phytosterols in the presence of cyclodextrins (12 mg/L), these compounds able to increase both the secretion and accumulation of phytosterols in the culture medium. Moreover, terbinafine induced a significant increase in intracellular squalene production, as seen after 168 h of treatment (497.0 ± 23.5 µg g dry weight -1 ) while its extracellular production only increased in the presence of cyclodextrins.The analysis of sqs and cas gene expression revealed that cyclodextrins did not induce genes encoding enzymes involved in the phytosterol biosynthetic pathway since the expression levels of sqs and cas genes in cyclodextrin-treated cells were lower than in control cells. The results, therefore, suggest that cyclodextrins were only able to release phytosterols from the cells to the extracellular medium, thus contributing to their acumulation. To sum up, D. carota

  1. Perturbations in the Photosynthetic Pigment Status Result in Photooxidation-Induced Crosstalk between Carotenoid and Porphyrin Biosynthetic Pathways

    Directory of Open Access Journals (Sweden)

    Joon-Heum Park

    2017-11-01

    Full Text Available Possible crosstalk between the carotenoid and porphyrin biosynthetic pathways under photooxidative conditions was investigated by using their biosynthetic inhibitors, norflurazon (NF and oxyfluorfen (OF. High levels of protoporphyrin IX (Proto IX accumulated in rice plants treated with OF, whereas Proto IX decreased in plants treated with NF. Both NF and OF treatments resulted in greater decreases in MgProto IX, MgProto IX methyl ester, and protochlorophyllide. Activities and transcript levels of most porphyrin biosynthetic enzymes, particularly in the Mg-porphyrin branch, were greatly down-regulated in NF and OF plants. In contrast, the transcript levels of GSA, PPO1, and CHLD as well as FC2 and HO2 were up-regulated in NF-treated plants, while only moderate increases in FC2 and HO2 were observed in the early stage of OF treatment. Phytoene, antheraxanthin, and zeaxanthin showed high accumulation in NF-treated plants, whereas other carotenoid intermediates greatly decreased. Transcript levels of carotenoid biosynthetic genes, PSY1 and PDS, decreased in response to NF and OF, whereas plants in the later stage of NF treatment exhibited up-regulation of BCH and VDE as well as recovery of PDS. However, perturbed porphyrin biosynthesis by OF did not noticeably influence levels of carotenoid metabolites, regardless of the strong down-regulation of carotenoid biosynthetic genes. Both NF and OF plants appeared to provide enhanced protection against photooxidative damage, not only by scavenging of Mg-porphyrins, but also by up-regulating FC2, HO2, and Fe-chelatase, particularly with increased levels of zeaxanthin via up-regulation of BCH and VDE in NF plants. On the other hand, the up-regulation of GSA, PPO1, and CHLD under inhibition of carotenogenic flux may be derived from the necessity to recover impaired chloroplast biogenesis during photooxidative stress. Our study demonstrates that perturbations in carotenoid and porphyrin biosynthesis coordinate

  2. Perturbations in the Photosynthetic Pigment Status Result in Photooxidation-Induced Crosstalk between Carotenoid and Porphyrin Biosynthetic Pathways.

    Science.gov (United States)

    Park, Joon-Heum; Tran, Lien H; Jung, Sunyo

    2017-01-01

    Possible crosstalk between the carotenoid and porphyrin biosynthetic pathways under photooxidative conditions was investigated by using their biosynthetic inhibitors, norflurazon (NF) and oxyfluorfen (OF). High levels of protoporphyrin IX (Proto IX) accumulated in rice plants treated with OF, whereas Proto IX decreased in plants treated with NF. Both NF and OF treatments resulted in greater decreases in MgProto IX, MgProto IX methyl ester, and protochlorophyllide. Activities and transcript levels of most porphyrin biosynthetic enzymes, particularly in the Mg-porphyrin branch, were greatly down-regulated in NF and OF plants. In contrast, the transcript levels of GSA, PPO1 , and CHLD as well as FC2 and HO2 were up-regulated in NF-treated plants, while only moderate increases in FC2 and HO2 were observed in the early stage of OF treatment. Phytoene, antheraxanthin, and zeaxanthin showed high accumulation in NF-treated plants, whereas other carotenoid intermediates greatly decreased. Transcript levels of carotenoid biosynthetic genes, PSY1 and PDS , decreased in response to NF and OF, whereas plants in the later stage of NF treatment exhibited up-regulation of BCH and VDE as well as recovery of PDS . However, perturbed porphyrin biosynthesis by OF did not noticeably influence levels of carotenoid metabolites, regardless of the strong down-regulation of carotenoid biosynthetic genes. Both NF and OF plants appeared to provide enhanced protection against photooxidative damage, not only by scavenging of Mg - porphyrins, but also by up-regulating FC2, HO2 , and Fe-chelatase, particularly with increased levels of zeaxanthin via up-regulation of BCH and VDE in NF plants. On the other hand, the up-regulation of GSA, PPO1 , and CHLD under inhibition of carotenogenic flux may be derived from the necessity to recover impaired chloroplast biogenesis during photooxidative stress. Our study demonstrates that perturbations in carotenoid and porphyrin biosynthesis coordinate the

  3. Decoding Biosynthetic Pathways in Plants by Pulse-Chase Strategies Using 13CO2 as a Universal Tracer

    Directory of Open Access Journals (Sweden)

    Adelbert Bacher

    2016-07-01

    Full Text Available 13CO2 pulse-chase experiments monitored by high-resolution NMR spectroscopy and mass spectrometry can provide 13C-isotopologue compositions in biosynthetic products. Experiments with a variety of plant species have documented that the isotopologue profiles generated with 13CO2 pulse-chase labeling are directly comparable to those that can be generated by the application of [U-13C6]glucose to aseptically growing plants. However, the application of the 13CO2 labeling technology is not subject to the experimental limitations that one has to take into account for experiments with [U-13C6]glucose and can be applied to plants growing under physiological conditions, even in the field. In practical terms, the results of biosynthetic studies with 13CO2 consist of the detection of pairs, triples and occasionally quadruples of 13C atoms that have been jointly contributed to the target metabolite, at an abundance that is well above the stochastic occurrence of such multiples. Notably, the connectivities of jointly transferred 13C multiples can have undergone modification by skeletal rearrangements that can be diagnosed from the isotopologue data. As shown by the examples presented in this review article, the approach turns out to be powerful in decoding the carbon topology of even complex biosynthetic pathways.

  4. A novel multifunctional O-methyltransferase implicated in a dual methylation pathway associated with lignin biosynthesis in loblolly pine.

    Science.gov (United States)

    Li, L; Popko, J L; Zhang, X H; Osakabe, K; Tsai, C J; Joshi, C P; Chiang, V L

    1997-05-13

    S-adenosyl-L-methionine (SAM)-dependent O-methyltransferases (OMTs) catalyze the methylation of hydroxycinnamic acid derivatives for the synthesis of methylated plant polyphenolics, including lignin. The distinction in the extent of methylation of lignins in angiosperms and gymnosperms, mediated by substrate-specific OMTs, represents one of the fundamental differences in lignin biosynthesis between these two classes of plants. In angiosperms, two types of structurally and functionally distinct lignin pathway OMTs, caffeic acid 3-O-methyltransferases (CAOMTs) and caffeoyl CoA 3-O-methyltransferases (CCoAOMTs), have been reported and extensively studied. However, little is known about lignin pathway OMTs in gymnosperms. We report here the first cloning of a loblolly pine (Pinus taeda) xylem cDNA encoding a multifunctional enzyme, SAM:hydroxycinnamic Acids/hydroxycinnamoyl CoA Esters OMT (AEOMT). The deduced protein sequence of AEOMT is partially similar to, but clearly distinguishable from, that of CAOMTs and does not exhibit any significant similarity with CCoAOMT protein sequences. However, functionally, yeast-expressed AEOMT enzyme catalyzed the methylation of CAOMT substrates, caffeic and 5-hydroxyferulic acids, as well as CCoAOMT substrates, caffeoyl CoA and 5-hydroxyferuloyl CoA esters, with similar specific activities and was completely inactive with substrates associated with flavonoid synthesis. The lignin-related substrates were also efficiently methylated in crude extracts of loblolly pine secondary xylem. Our results support the notion that, in the context of amino acid sequence and biochemical function, AEOMT represents a novel SAM-dependent OMT, with both CAOMT and CCoAOMT activities and thus the potential to mediate a dual methylation pathway in lignin biosynthesis in loblolly pine xylem.

  5. A novel multifunctional O-methyltransferase implicated in a dual methylation pathway associated with lignin biosynthesis in loblolly pine

    Science.gov (United States)

    Li, Laigeng; Popko, Jacqueline L.; Zhang, Xing-Hai; Osakabe, Keishi; Tsai, Chung-Jui; Joshi, Chandrashekhar P.; Chiang, Vincent L.

    1997-01-01

    S-adenosyl-l-methionine (SAM)-dependent O-methyltransferases (OMTs) catalyze the methylation of hydroxycinnamic acid derivatives for the synthesis of methylated plant polyphenolics, including lignin. The distinction in the extent of methylation of lignins in angiosperms and gymnosperms, mediated by substrate-specific OMTs, represents one of the fundamental differences in lignin biosynthesis between these two classes of plants. In angiosperms, two types of structurally and functionally distinct lignin pathway OMTs, caffeic acid 3-O-methyltransferases (CAOMTs) and caffeoyl CoA 3-O-methyltransferases (CCoAOMTs), have been reported and extensively studied. However, little is known about lignin pathway OMTs in gymnosperms. We report here the first cloning of a loblolly pine (Pinus taeda) xylem cDNA encoding a multifunctional enzyme, SAM:hydroxycinnamic Acids/hydroxycinnamoyl CoA Esters OMT (AEOMT). The deduced protein sequence of AEOMT is partially similar to, but clearly distinguishable from, that of CAOMTs and does not exhibit any significant similarity with CCoAOMT protein sequences. However, functionally, yeast-expressed AEOMT enzyme catalyzed the methylation of CAOMT substrates, caffeic and 5-hydroxyferulic acids, as well as CCoAOMT substrates, caffeoyl CoA and 5-hydroxyferuloyl CoA esters, with similar specific activities and was completely inactive with substrates associated with flavonoid synthesis. The lignin-related substrates were also efficiently methylated in crude extracts of loblolly pine secondary xylem. Our results support the notion that, in the context of amino acid sequence and biochemical function, AEOMT represents a novel SAM-dependent OMT, with both CAOMT and CCoAOMT activities and thus the potential to mediate a dual methylation pathway in lignin biosynthesis in loblolly pine xylem. PMID:9144260

  6. Structure, function and regulation of the enzymes in the starch biosynthetic pathway.

    Energy Technology Data Exchange (ETDEWEB)

    Geiger, Jim

    2013-11-30

    structure of ADP- Glucose pyrophosphorylase from potato in its inhibited conformation, and bound to both ATP and ADP-glucose. In addition, we have determined the first structure of glycogen synthase in its "closed", catalytically active conformation bound to ADP-glucose. We also determined the structure of glycogen synthase bound to malto-oligosaccharides, showing for the first time that an enzyme in the starch biosynthetic pathway recognizes glucans not just in its active site but on binding sites on the surface of the enzyme ten’s of Angstroms from the active site. In addition our structure of a glycogen branching enzyme bound to malto-oligosaccharides identified seven distinct binding sites distributed about the surface of the enzyme. We will now determine the function of these sites to get a molecular-level picture of exactly how these enzymes interact with their polymeric substrates and confer specificity leading to the complex structure of the starch granule. We will extend our studies to other isoforms of the enzymes, to understand how their structures give rise to their distinct function. Our goal is to understand what accounts for the various functional differences between SS and SBE isoforms at a molecular level.

  7. Synthesis of C-Glucosylated Octaketide Anthraquinones in Nicotiana benthamiana by Using a Multispecies-Based Biosynthetic Pathway.

    Science.gov (United States)

    Andersen-Ranberg, Johan; Kongstad, Kenneth Thermann; Nafisi, Majse; Staerk, Dan; Okkels, Finn Thyge; Mortensen, Uffe Hasbro; Lindberg Møller, Birger; Frandsen, Rasmus John Normand; Kannangara, Rubini

    2017-10-05

    Carminic acid is a C-glucosylated octaketide anthraquinone and the main constituent of the natural dye carmine (E120), possessing unique coloring, stability, and solubility properties. Despite being used since ancient times, longstanding efforts to elucidate its route of biosynthesis have been unsuccessful. Herein, a novel combination of enzymes derived from a plant (Aloe arborescens, Aa), a bacterium (Streptomyces sp. R1128, St), and an insect (Dactylopius coccus, Dc) that allows for the biosynthesis of the C-glucosylated anthraquinone, dcII, a precursor for carminic acid, is reported. The pathway, which consists of AaOKS, StZhuI, StZhuJ, and DcUGT2, presents an alternative biosynthetic approach for the production of polyketides by using a type III polyketide synthase (PKS) and tailoring enzymes originating from a type II PKS system. The current study showcases the power of using transient expression in Nicotiana benthamiana for efficient and rapid identification of functional biosynthetic pathways, including both soluble and membrane-bound enzymes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. A Novel Antibiotic Mechanism of l-Cyclopropylalanine Blocking the Biosynthetic Pathway of Essential Amino Acid l-Leucine

    Directory of Open Access Journals (Sweden)

    Bingji Ma

    2017-12-01

    Full Text Available The unusual amino acid l-cyclopropylalanine was isolated from the mushroom Amanita virgineoides after detection in an anti-fungal screening test. l-Cyclopropylalanine was found to exhibit broad-spectrum inhibition against fungi and bacteria. The anti-fungal activity was found to be abolished in the presence of the amino acid l-leucine, but not any other amino acids, indicating that l-cyclopropylalanine may block the biosynthesis of the essential amino acid l-leucine, thereby inhibiting fungal and bacteria growth. Further biochemical studies found l-cyclopropylalanine indeed inhibits α-isopropylmalate synthase (α-IMPS, the enzyme that catalyzes the rate-limiting step in the biosynthetic pathway of l-leucine. Inhibition of essential l-leucine synthesis in fungal and bacteria organisms, a pathway absent in host organisms such as humans, may represent a novel antibiotic mechanism to counter the ever-increasing problem of drug resistance to existing antibiotics.

  9. Identification of an unusual type II thioesterase in the dithiolopyrrolone antibiotics biosynthetic pathway

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Ying; Bai, Silei; Liu, Jingjing; Yang, Liyuan [National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070 (China); Han, Li; Huang, Xueshi [Institute of Microbial Pharmaceuticals, College of Life and Health Sciences, Northeastern University, Shenyang 110819 (China); He, Jing, E-mail: hejingjj@mail.hzau.edu.cn [National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070 (China)

    2016-04-22

    Dithiolopyrrolone group antibiotics characterized by an electronically unique dithiolopyrrolone heterobicyclic core are known for their antibacterial, antifungal, insecticidal and antitumor activities. Recently the biosynthetic gene clusters for two dithiolopyrrolone compounds, holomycin and thiomarinol, have been identified respectively in different bacterial species. Here, we report a novel dithiolopyrrolone biosynthetic gene cluster (aut) isolated from Streptomyces thioluteus DSM 40027 which produces two pyrrothine derivatives, aureothricin and thiolutin. By comparison with other characterized dithiolopyrrolone clusters, eight genes in the aut cluster were verified to be responsible for the assembly of dithiolopyrrolone core. The aut cluster was further confirmed by heterologous expression and in-frame gene deletion experiments. Intriguingly, we found that the heterogenetic thioesterase HlmK derived from the holomycin (hlm) gene cluster in Streptomyces clavuligerus significantly improved heterologous biosynthesis of dithiolopyrrolones in Streptomyces albus through coexpression with the aut cluster. In the previous studies, HlmK was considered invalid because it has a Ser to Gly point mutation within the canonical Ser-His-Asp catalytic triad of thioesterases. However, gene inactivation and complementation experiments in our study unequivocally demonstrated that HlmK is an active distinctive type II thioesterase that plays a beneficial role in dithiolopyrrolone biosynthesis. - Highlights: • Cloning of the aureothricin biosynthetic gene cluster from Streptomyces thioluteus DSM 40027. • Identification of the aureothricin gene cluster by heterologous expression and in-frame gene deletion. • The heterogenetic thioesterase HlmK significantly improved dithiolopyrrolones production of the aureothricin gene cluster. • Identification of HlmK as an unusual type II thioesterase.

  10. Identification of an unusual type II thioesterase in the dithiolopyrrolone antibiotics biosynthetic pathway

    International Nuclear Information System (INIS)

    Zhai, Ying; Bai, Silei; Liu, Jingjing; Yang, Liyuan; Han, Li; Huang, Xueshi; He, Jing

    2016-01-01

    Dithiolopyrrolone group antibiotics characterized by an electronically unique dithiolopyrrolone heterobicyclic core are known for their antibacterial, antifungal, insecticidal and antitumor activities. Recently the biosynthetic gene clusters for two dithiolopyrrolone compounds, holomycin and thiomarinol, have been identified respectively in different bacterial species. Here, we report a novel dithiolopyrrolone biosynthetic gene cluster (aut) isolated from Streptomyces thioluteus DSM 40027 which produces two pyrrothine derivatives, aureothricin and thiolutin. By comparison with other characterized dithiolopyrrolone clusters, eight genes in the aut cluster were verified to be responsible for the assembly of dithiolopyrrolone core. The aut cluster was further confirmed by heterologous expression and in-frame gene deletion experiments. Intriguingly, we found that the heterogenetic thioesterase HlmK derived from the holomycin (hlm) gene cluster in Streptomyces clavuligerus significantly improved heterologous biosynthesis of dithiolopyrrolones in Streptomyces albus through coexpression with the aut cluster. In the previous studies, HlmK was considered invalid because it has a Ser to Gly point mutation within the canonical Ser-His-Asp catalytic triad of thioesterases. However, gene inactivation and complementation experiments in our study unequivocally demonstrated that HlmK is an active distinctive type II thioesterase that plays a beneficial role in dithiolopyrrolone biosynthesis. - Highlights: • Cloning of the aureothricin biosynthetic gene cluster from Streptomyces thioluteus DSM 40027. • Identification of the aureothricin gene cluster by heterologous expression and in-frame gene deletion. • The heterogenetic thioesterase HlmK significantly improved dithiolopyrrolones production of the aureothricin gene cluster. • Identification of HlmK as an unusual type II thioesterase.

  11. Perturbations of carotenoid and tetrapyrrole biosynthetic pathways result in differential alterations in chloroplast function and plastid signaling

    International Nuclear Information System (INIS)

    Park, Joon-Heum; Jung, Sunyo

    2017-01-01

    In this study, we used the biosynthetic inhibitors of carotenoid and tetrapyrrole biosynthetic pathways, norflurazon (NF) and oxyfluorfen (OF), as tools to gain insight into mechanisms of photooxidation in rice plants. NF resulted in bleaching symptom on leaves of the treated plants, whereas OF treatment developed a fast symptom of an apparent necrotic phenotype. Both plants exhibited decreases in photosynthetic efficiency, as indicated by F v /F m . NF caused severe disruption in thylakoid membranes, whereas OF-treated plants exhibited disruption of chloroplast envelope and plasma membrane. Levels of Lhca and Lhcb proteins in photosystem I (PSI) and PSII were reduced by photooxidative stress in NF- and OF-treated plants, with a greater decrease in NF plants. The down-regulation of nuclear-encoded photosynthesis genes Lhcb and rbcS was also found in both NF- and OF-treated plants, whereas plastid-encoded photosynthetic genes including RbcL, PsaC, and PsbD accumulated normally in NF plants but decreased drastically in OF plants. This proposes that the plastids in NF plants retain their potential to develop thylakoid membranes and that photobleaching is mainly controlled by nuclear genes. Distinct photooxidation patterns between NF- and OF-treated plants developed differential signaling, which might enable the plant to coordinate the expression of photosynthetic genes from the nuclear and plastidic genomes. - Highlights: • Two modes of photooxidation by carotenoid and tetrapyrrole biosynthetic inhibitors. • We examine differential alterations in chloroplast function and plastid signaling. • NF and OF cause differential alterations in chloroplast ultrastructure and function. • Photooxidation coordinates photosynthetic gene expression from nucleus and plastid.

  12. Perturbations of carotenoid and tetrapyrrole biosynthetic pathways result in differential alterations in chloroplast function and plastid signaling.

    Science.gov (United States)

    Park, Joon-Heum; Jung, Sunyo

    2017-01-22

    In this study, we used the biosynthetic inhibitors of carotenoid and tetrapyrrole biosynthetic pathways, norflurazon (NF) and oxyfluorfen (OF), as tools to gain insight into mechanisms of photooxidation in rice plants. NF resulted in bleaching symptom on leaves of the treated plants, whereas OF treatment developed a fast symptom of an apparent necrotic phenotype. Both plants exhibited decreases in photosynthetic efficiency, as indicated by F v /F m . NF caused severe disruption in thylakoid membranes, whereas OF-treated plants exhibited disruption of chloroplast envelope and plasma membrane. Levels of Lhca and Lhcb proteins in photosystem I (PSI) and PSII were reduced by photooxidative stress in NF- and OF-treated plants, with a greater decrease in NF plants. The down-regulation of nuclear-encoded photosynthesis genes Lhcb and rbcS was also found in both NF- and OF-treated plants, whereas plastid-encoded photosynthetic genes including RbcL, PsaC, and PsbD accumulated normally in NF plants but decreased drastically in OF plants. This proposes that the plastids in NF plants retain their potential to develop thylakoid membranes and that photobleaching is mainly controlled by nuclear genes. Distinct photooxidation patterns between NF- and OF-treated plants developed differential signaling, which might enable the plant to coordinate the expression of photosynthetic genes from the nuclear and plastidic genomes. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Genomic characterization of a new endophytic Streptomyces kebangsaanensis identifies biosynthetic pathway gene clusters for novel phenazine antibiotic production

    Directory of Open Access Journals (Sweden)

    Juwairiah Remali

    2017-11-01

    Full Text Available Background Streptomyces are well known for their capability to produce many bioactive secondary metabolites with medical and industrial importance. Here we report a novel bioactive phenazine compound, 6-((2-hydroxy-4-methoxyphenoxy carbonyl phenazine-1-carboxylic acid (HCPCA extracted from Streptomyces kebangsaanensis, an endophyte isolated from the ethnomedicinal Portulaca oleracea. Methods The HCPCA chemical structure was determined using nuclear magnetic resonance spectroscopy. We conducted whole genome sequencing for the identification of the gene cluster(s believed to be responsible for phenazine biosynthesis in order to map its corresponding pathway, in addition to bioinformatics analysis to assess the potential of S. kebangsaanensis in producing other useful secondary metabolites. Results The S. kebangsaanensis genome comprises an 8,328,719 bp linear chromosome with high GC content (71.35% consisting of 12 rRNA operons, 81 tRNA, and 7,558 protein coding genes. We identified 24 gene clusters involved in polyketide, nonribosomal peptide, terpene, bacteriocin, and siderophore biosynthesis, as well as a gene cluster predicted to be responsible for phenazine biosynthesis. Discussion The HCPCA phenazine structure was hypothesized to derive from the combination of two biosynthetic pathways, phenazine-1,6-dicarboxylic acid and 4-methoxybenzene-1,2-diol, originated from the shikimic acid pathway. The identification of a biosynthesis pathway gene cluster for phenazine antibiotics might facilitate future genetic engineering design of new synthetic phenazine antibiotics. Additionally, these findings confirm the potential of S. kebangsaanensis for producing various antibiotics and secondary metabolites.

  14. Carotenoid Biosynthetic Pathways Are Regulated by a Network of Multiple Cascades of Alternative Sigma Factors in Azospirillum brasilense Sp7.

    Science.gov (United States)

    Rai, Ashutosh Kumar; Dubey, Ashutosh Prakash; Kumar, Santosh; Dutta, Debashis; Mishra, Mukti Nath; Singh, Bhupendra Narain; Tripathi, Anil Kumar

    2016-11-01

    Carotenoids constitute an important component of the defense system against photooxidative stress in bacteria. In Azospirillum brasilense Sp7, a nonphotosynthetic rhizobacterium, carotenoid synthesis is controlled by a pair of extracytoplasmic function sigma factors (RpoEs) and their cognate zinc-binding anti-sigma factors (ChrRs). Its genome harbors two copies of the gene encoding geranylgeranyl pyrophosphate synthase (CrtE), the first critical step in the carotenoid biosynthetic pathway in bacteria. Inactivation of each of two crtE paralogs found in A. brasilense caused reduction in carotenoid content, suggesting their involvement in carotenoid synthesis. However, the effect of crtE1 deletion was more pronounced than that of crtE2 deletion. Out of the five paralogs of rpoH in A. brasilense, overexpression of rpoH1 and rpoH2 enhanced carotenoid synthesis. Promoters of crtE2 and rpoH2 were found to be dependent on RpoH2 and RpoE1, respectively. Using a two-plasmid system in Escherichia coli, we have shown that the crtE2 gene of A. brasilense Sp7 is regulated by two cascades of sigma factors: one consisting of RpoE1and RpoH2 and the other consisting of RpoE2 and RpoH1. In addition, expression of crtE1 was upregulated indirectly by RpoE1 and RpoE2. This study shows, for the first time in any carotenoid-producing bacterium, that the regulation of carotenoid biosynthetic pathway involves a network of multiple cascades of alternative sigma factors. Carotenoids play a very important role in coping with photooxidative stress in prokaryotes and eukaryotes. Although extracytoplasmic function (ECF) sigma factors are known to directly regulate the expression of carotenoid biosynthetic genes in bacteria, regulation of carotenoid biosynthesis by one or multiple cascades of sigma factors had not been reported. This study provides the first evidence of the involvement of multiple cascades of sigma factors in the regulation of carotenoid synthesis in any bacterium by showing the

  15. The Phenylpropanoid Pathway and Lignin in Defense against Ganoderma boninense Colonized Root Tissues in Oil Palm (Elaeis guineensis Jacq.

    Directory of Open Access Journals (Sweden)

    Nisha T. Govender

    2017-08-01

    Full Text Available Basal stem rot, caused by the basidiomycete fungus, Ganoderma boninense, is an economically devastating disease in Malaysia. Our study investigated the changes in lignin content and composition along with activity and expression of the phenylpropanoid pathway enzymes and genes in oil palm root tissues during G. boninense infection. We sampled control (non-inoculated and infected (inoculated seedlings at seven time points [1, 2, 3, 4, 8, and 12 weeks post-inoculation (wpi] in a randomized design. The expression profiles of phenylalanine ammonia lyase (PAL, cinnamyl alcohol dehydrogenase (CAD, and peroxidase (POD genes were monitored at 1, 2, and 3 wpi using real-time quantitative polymerase chain reaction. Seedlings at 4, 8, and 12 wpi were screened for lignin content, lignin composition, enzyme activities (PAL, CAD, and POD, growth (weight and height, and disease severity (DS. Gene expression analysis demonstrated up-regulation of PAL, CAD, and POD genes in the infected seedlings, relative to the control seedlings at 1, 2, and 3 wpi. At 2 and 3 wpi, CAD showed highest transcript levels compared to PAL and POD. DS increased progressively throughout sampling, with 5, 34, and 69% at 4, 8, and 12 wpi, respectively. Fresh weight and height of the infected seedlings were significantly lower compared to the control seedlings at 8 and 12 wpi. Lignin content of the infected seedlings at 4 wpi was significantly higher than the control seedlings, remained elicited with no change at 8 wpi, and then collapsed with a significant reduction at 12 wpi. The nitrobenzene oxidation products of oil palm root lignin yielded both syringyl and guaiacyl monomers. Accumulation of lignin in the infected seedlings was in parallel to increased syringyl monomers, at 4 and 8 wpi. The activities of PAL and CAD enzymes in the infected seedlings at DS = 5–34% were significantly higher than the control seedlings and thereafter collapsed at DS = 69%.

  16. The Phenylpropanoid Pathway and Lignin in Defense against Ganoderma boninense Colonized Root Tissues in Oil Palm (Elaeis guineensis Jacq.).

    Science.gov (United States)

    Govender, Nisha T; Mahmood, Maziah; Seman, Idris A; Wong, Mui-Yun

    2017-01-01

    Basal stem rot, caused by the basidiomycete fungus, Ganoderma boninense , is an economically devastating disease in Malaysia. Our study investigated the changes in lignin content and composition along with activity and expression of the phenylpropanoid pathway enzymes and genes in oil palm root tissues during G. boninense infection. We sampled control (non-inoculated) and infected (inoculated) seedlings at seven time points [1, 2, 3, 4, 8, and 12 weeks post-inoculation (wpi)] in a randomized design. The expression profiles of phenylalanine ammonia lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), and peroxidase (POD) genes were monitored at 1, 2, and 3 wpi using real-time quantitative polymerase chain reaction. Seedlings at 4, 8, and 12 wpi were screened for lignin content, lignin composition, enzyme activities (PAL, CAD, and POD), growth (weight and height), and disease severity (DS). Gene expression analysis demonstrated up-regulation of PAL, CAD, and POD genes in the infected seedlings, relative to the control seedlings at 1, 2, and 3 wpi. At 2 and 3 wpi, CAD showed highest transcript levels compared to PAL and POD. DS increased progressively throughout sampling, with 5, 34, and 69% at 4, 8, and 12 wpi, respectively. Fresh weight and height of the infected seedlings were significantly lower compared to the control seedlings at 8 and 12 wpi. Lignin content of the infected seedlings at 4 wpi was significantly higher than the control seedlings, remained elicited with no change at 8 wpi, and then collapsed with a significant reduction at 12 wpi. The nitrobenzene oxidation products of oil palm root lignin yielded both syringyl and guaiacyl monomers. Accumulation of lignin in the infected seedlings was in parallel to increased syringyl monomers, at 4 and 8 wpi. The activities of PAL and CAD enzymes in the infected seedlings at DS = 5-34% were significantly higher than the control seedlings and thereafter collapsed at DS = 69%.

  17. Estimating P-coverage of biosynthetic pathways in DNA libraries and screening by genetic selection: biotin biosynthesis in the marine microorganism Chromohalobacter.

    Science.gov (United States)

    Kim, Eun Jin; Angell, Scott; Janes, Jeff; Watanabe, Coran M H

    2008-06-01

    Traditional approaches to natural product discovery involve cell-based screening of natural product extracts followed by compound isolation and characterization. Their importance notwithstanding, continued mining leads to depletion of natural resources and the reisolation of previously identified metabolites. Metagenomic strategies aimed at localizing the biosynthetic cluster genes and expressing them in surrogate hosts offers one possible alternative. A fundamental question that naturally arises when pursuing such a strategy is, how large must the genomic library be to effectively represent the genome of an organism(s) and the biosynthetic gene clusters they harbor? Such an issue is certainly augmented in the absence of expensive robotics to expedite colony picking and/or screening of clones. We have developed an algorism, named BPC (biosynthetic pathway coverage), supported by molecular simulations to deduce the number of BAC clones required to achieve proper coverage of the genome and their respective biosynthetic pathways. The strategy has been applied to the construction of a large-insert BAC library from a marine microorganism, Hon6 (isolated from Honokohau, Maui) thought to represent a new species. The genomic library is constructed with a BAC yeast shuttle vector pClasper lacZ paving the way for the culturing of libraries in both prokaryotic and eukaryotic hosts. Flow cytometric methods are utilized to estimate the genome size of the organism and BPC implemented to assess P-coverage or percent coverage. A genetic selection strategy is illustrated, applications of which could expedite screening efforts in the identification and localization of biosynthetic pathways from marine microbial consortia, offering a powerful complement to genome sequencing and degenerate probe strategies. Implementing this approach, we report on the biotin biosynthetic pathway from the marine microorganism Hon6.

  18. Production of 2-deoxyribose 5-phosphate from fructose to demonstrate a potential of artificial bio-synthetic pathway using thermophilic enzymes.

    Science.gov (United States)

    Honda, Kohsuke; Maya, Shohei; Omasa, Takeshi; Hirota, Ryuichi; Kuroda, Akio; Ohtake, Hisao

    2010-08-02

    Six thermophilic enzymes from Thermus thermophilus were used to construct an 'artificial bio-synthetic pathway' for the production of 2-deoxyribose 5-phosphate from fructose. By a simple operation using six recombinant Escherichia coli strains producing the thermophilic enzymes, respectively, fructose was converted to 2-deoxyribose 5-phosphate with a molar yield of 55%. Copyright 2010 Elsevier B.V. All rights reserved.

  19. Novel key metabolites reveal further branching of the roquefortine/meleagrin biosynthetic pathway.

    Science.gov (United States)

    Ries, Marco I; Ali, Hazrat; Lankhorst, Peter P; Hankemeier, Thomas; Bovenberg, Roel A L; Driessen, Arnold J M; Vreeken, Rob J

    2013-12-27

    Metabolic profiling and structural elucidation of novel secondary metabolites obtained from derived deletion strains of the filamentous fungus Penicillium chrysogenum were used to reassign various previously ascribed synthetase genes of the roquefortine/meleagrin pathway to their corresponding products. Next to the structural characterization of roquefortine F and neoxaline, which are for the first time reported for P. chrysogenum, we identified the novel metabolite roquefortine L, including its degradation products, harboring remarkable chemical structures. Their biosynthesis is discussed, questioning the exclusive role of glandicoline A as key intermediate in the pathway. The results reveal that further enzymes of this pathway are rather unspecific and catalyze more than one reaction, leading to excessive branching in the pathway with meleagrin and neoxaline as end products of two branches.

  20. Improved Wood Properties Through Genetic Manipulation: Engineering of Syringyl Lignin in Softwood Species Through Xylem-Specific Expression of Hardwood Syringyl Monolignol Pathway Genes

    Energy Technology Data Exchange (ETDEWEB)

    Chandrashekhar P. Joshi; Vincent L. Chiang

    2009-01-29

    Project Objective: Our long-term goal is to genetically engineer higher value raw materials with desirable wood properties to promote energy efficiency, international competitiveness, and environmental responsiveness of the U.S. forest products industry. The immediate goal of this project was to produce the first higher value softwood raw materials engineered with a wide range of syringyl lignin quantities. Summary: The most important wood property affecting directly the levels of energy, chemical and bleaching requirements for kraft pulp production is lignin. Softwoods contain almost exclusively chemically resistant guaiacyl (G) lignin, whereas hardwoods have more reactive or easily degradable lignins of the guaiacyl (G)-syringyl (S) type. It is also well established that the reactive S lignin component is the key factor that permits much lower effective alkali and temperature, shorter pulping time and less bleaching stages for processing hardwoods than for softwoods. Furthermore, our pulping kinetic study explicitly demonstrated that every increase in one unit of the lignin S/G ratio would roughly double the rate of lignin removal. These are clear evidence that softwoods genetically engineered with S lignin are keys to revolutionizing the energy efficiency and enhancing the environmental performance of this industry. Softwoods and hardwoods share the same genetic mechanisms for the biosynthesis of G lignin. However, in hardwoods, three additional genes branch out from the G-lignin pathway and become specifically engaged in regulating S lignin biosynthesis. In this research, we simultaneously transferred aspen S-specific genes into a model softwood, black spruce, to engineer S lignin.

  1. Bioenergetic coupling between membrane transport systems and biosynthetic pathways essential for cell cycle progression

    International Nuclear Information System (INIS)

    Leister, K.J.; Cutry, A.F.; Wenner, C.E.

    1986-01-01

    Recently, it has been shown that there exists a point in the cell cycle (approximately 2 h prior to S phase entry) when (Na + /K + )ATPase pump activity is no longer needed for progression through the cycle. These data suggests that pump activity is critical in the biosynthetic processes which enables the cell to proceed through the G 1 phase. A scheme is proposed which is currently being tested that (Na + /K + )ATPase pump activity serves as the driving force in the regulation of other membrane transport processes critical for cell proliferation. For example, in post-confluent quiescent C3H-10T1/2 fibroblasts, when [K + ]/sub o/ is lowered just below the K/sub m/ of the pump for K + there is a 10-fold increase in 3 H-uridine uptake into both acid soluble and insoluble cell fractions. By modulation of the pump in this manner, glucose utilization is enhanced whereas inhibition of the pump by ouabain suppresses glucose utilization. In both methods of affecting the pump, 3 H-leucine incorporation is inhibited. Electron acceptors that influence the redox state of the cell have been shown to both stimulate or inhibit cell cycle progression. Under conditions where [K + ]/sub o/ is lowered, the nucleoside uptake responses observed were modified by electron acceptors depending on the ability to oxidize NAD(P)H directly or to interact with a cytochrome-like component, (e.g. phenazine methosulfate) reversed the enhanced uridine uptake and p-phenylene diamine further enhanced the uridine uptake response. These findings suggest that a plasma membrane redox system (presumably cyt-c like) is linked to nucleoside transport which is subject to (Na + /K + )ATPase activity

  2. Targeted Gene Disruption of the Cyclo (L-Phe, L-Pro Biosynthetic Pathway in Streptomyces sp. US24 Strain

    Directory of Open Access Journals (Sweden)

    Samiha Sioud

    2007-01-01

    Full Text Available We have previously isolated a new actinomycete strain from Tunisian soil called Streptomyces sp. US24, and have shown that it produces two bioactive molecules including a Cyclo (L-Phe, L-Pro diketopiperazine (DKP. To identify the structural genes responsible for the synthesis of this DKP derivative, a PCR amplification (696 bp was carried out using the Streptomyces sp. US24 genomic DNA as template and two degenerate oligonucleotides designed by analogy with genes encoding peptide synthetases (NRPS. The detection of DKP derivative biosynthetic pathway of the Streptomyces sp. US24 strain was then achieved by gene disruption via homologous recombination using a suicide vector derived from the conjugative plasmid pSET152 and containing the PCR product. Chromatography analysis, biological tests and spectroscopic studies of supernatant cultures of the wild-type Streptomyces sp. US24 strain and three mutants obtained by this gene targeting disruption approach showed that the amplified DNA fragment is required for Cyclo (L-Phe, L-Pro biosynthesis in Streptomyces sp. US24 strain. This DKP derivative seems to be produced either directly via a nonribosomal pathway or as a side product in the course of nonribosomal synthesis of a longer peptide.

  3. Aspergillus nidulans as a platform for discovery and characterization of complex biosynthetic pathways

    DEFF Research Database (Denmark)

    Anyaogu, Diana Chinyere

    in industrial applications for the productionof these bioactive compounds and other chemicals as well as for enzyme production. Especially Aspergillusniger and Aspergillus oryzae are used as industrial workhorses for the production of various enzymes. Manyof the secreted proteins are glycosylated, indicating...... aspharmaceuticals. Access to this unexploited reservoir is hampered as many of the clusters are silent orbarely expressed under laboratory conditions. Methods for activating these pathways are thereforeessential for pathway discovery and elucidation.  Filamentous fungi and Aspergillus species in particular are used...... that glycosylation plays an important role in thesecretory pathway. Thus, understanding the role and process of glycosylation will enable directedglycoengineering in Aspergilli to improve protein production and expand the repertoire of proteins, whichcan be produced by these fungi. Aspergillus nidulans has been used...

  4. [Construction of Corynebacterium crenatum AS 1.542 δ argR and analysis of transcriptional levels of the related genes of arginine biosynthetic pathway].

    Science.gov (United States)

    Chen, Xuelan; Tang, Li; Jiao, Haitao; Xu, Feng; Xiong, Yonghua

    2013-01-04

    ArgR, coded by the argR gene from Corynebacterium crenatum AS 1.542, acts as a negative regulator in arginine biosynthetic pathway. However, the effect of argR on transcriptional levels of the related biosynthetic genes has not been reported. Here, we constructed a deletion mutant of argR gene: C. crenatum AS 1.542 Delta argR using marker-less knockout technology, and compared the changes of transcriptional levels of the arginine biosynthetic genes between the mutant strain and the wild-type strain. We used marker-less knockout technology to construct C. crenatum AS 1.542 Delta argR and analyzed the changes of the relate genes at the transcriptional level using real-time fluorescence quantitative PCR. C. crenatum AS 1.542 Delta argR was successfully obtained and the transcriptional level of arginine biosynthetic genes in this mutant increased significantly with an average of about 162.1 folds. The arginine biosynthetic genes in C. crenatum are clearly controlled by the negative regulator ArgR. However, the deletion of this regulator does not result in a clear change in arginine production in the bacteria.

  5. Responses of Synechocystis sp. PCC 6803 to heterologous biosynthetic pathways

    DEFF Research Database (Denmark)

    Vavitsas, Konstantinos; Rue, Emil Østergaard; Stefánsdóttir, Lára Kristín

    2017-01-01

    BACKGROUND: There are an increasing number of studies regarding genetic manipulation of cyanobacteria to produce commercially interesting compounds. The majority of these works study the expression and optimization of a selected heterologous pathway, largely ignoring the wholeness and complexity...... different compounds, the cyanogenic glucoside dhurrin and the diterpenoid 13R-manoyl oxide in Synechocystis PCC 6803. We used genome-scale metabolic modelling to study fluxes in individual reactions and pathways, and we determined the concentrations of key metabolites, such as amino acids, carotenoids...

  6. Sugarcane expressed sequences tags (ESTs encoding enzymes involved in lignin biosynthesis pathways

    Directory of Open Access Journals (Sweden)

    Ramos Rose Lucia Braz

    2001-01-01

    Full Text Available Lignins are phenolic polymers found in the secondary wall of plant conductive systems where they play an important role by reducing the permeability of the cell wall to water. Lignins are also responsible for the rigidity of the cell wall and are involved in mechanisms of resistance to pathogens. The metabolic routes and enzymes involved in synthesis of lignins have been largely characterized and representative genes that encode enzymes involved in these processes have been cloned from several plant species. The synthesis of lignins is liked to the general metabolism of the phenylpropanoids in plants, having enzymes (e.g. phenylalanine ammonia-lyase (PAL, cinnamate 4-hydroxylase (C4H and caffeic acid O-methyltransferase (COMT common to other processes as well as specific enzymes such as cinnamoyl-CoA reductase (CCR and cinnamyl alcohol dehydrogenase (CAD. Some maize and sorghum mutants, shown to have defective in CAD and/or COMT activity, are easier to digest because they have a reduced lignin content, something which has motivated different research groups to alter the lignin content and composition of model plants by genetic engineering try to improve, for example, the efficiency of paper pulping and digestibility. In the work reported in this paper, we have made an inventory of the sugarcane expressed sequence tag (EST coding for enzymes involved in lignin metabolism which are present in the sugarcane EST genome project (SUCEST database. Our analysis focused on the key enzymes ferulate-5-hydroxylase (F5H, caffeic acid O-methyltransferase (COMT, caffeoyl CoA O-methyltransferase (CCoAOMT, hydroxycinnamate CoA ligase (4CL, cinnamoyl-CoA reductase (CCR and cinnamyl alcohol dehydrogenase (CAD. The comparative analysis of these genes with those described in other species could be used as molecular markers for breeding as well as for the manipulation of lignin metabolism in sugarcane.

  7. NMR characterization of altered lignins extracted from tobacco plants down-regulated for lignification enzymes cinnamylalcohol dehydrogenase and cinnamoyl-CoA reductase

    OpenAIRE

    Ralph, John; Hatfield, Ronald D.; Piquemal, Joël; Yahiaoui, Nabila; Pean, Michel; Lapierre, Catherine; Boudet, Alain M.

    1998-01-01

    Homologous antisense constructs were used to down-regulate tobacco cinnamyl-alcohol dehydrogenase (CAD; EC 1.1.1.195) and cinnamoyl-CoA reductase (CCR; EC 1.2.1.44) activities in the lignin monomer biosynthetic pathway. CCR converts activated cinnamic acids (hydroxycinnamoyl–SCoAs) to cinnamaldehydes; cinnamaldehydes are then reduced to cinnamyl alcohols by CAD. The transformations caused the incorporation of nontraditional components into the extractable tobacco lignins, as evidenced by NMR....

  8. Evolutionary origins and functions of the carotenoid biosynthetic pathway in marine diatoms

    Czech Academy of Sciences Publication Activity Database

    Coesel, S.; Oborník, Miroslav; Varela, J.; Falciatore, A.; Bowler, C.

    2008-01-01

    Roč. 3, č. 8 (2008), s. 1-16 E-ISSN 1932-6203 R&D Projects: GA AV ČR IAA500220502 Institutional research plan: CEZ:AV0Z60220518 Keywords : marine diatoms * carotenoid pathway * evolution Subject RIV: EB - Genetics ; Molecular Biology

  9. Chapter 3: Omics Advances of Biosynthetic Pathways of Isoprenoid Production in Microalgae

    Energy Technology Data Exchange (ETDEWEB)

    Paniagua-Michel, J.; Subramanian, Venkataramanan

    2017-01-01

    In this chapter, the current status of microalgal isoprenoids and the role of omics technologies, or otherwise specified, in bioproducts optimization and applications are reviewed. Emphasis is focused in the metabolic pathways of microalgae involved in the production of commercially important products, namely, hydrocarbons and biofuels, nutraceuticals, and pharmaceuticals.

  10. De novo transcriptome assembly and the putative biosynthetic pathway of steroidal sapogenins of Dioscorea composita.

    Directory of Open Access Journals (Sweden)

    Xia Wang

    Full Text Available The plant Dioscorea composita has important applications in the medical and energy industries, and can be used for the extraction of steroidal sapogenins (important raw materials for the synthesis of steroidal drugs and bioethanol production. However, little is known at the genetic level about how sapogenins are biosynthesized in this plant. Using Illumina deep sequencing, 62,341 unigenes were obtained by assembling its transcriptome, and 27,720 unigenes were annotated. Of these, 8,022 unigenes were mapped to 243 specific pathways, and 531 unigenes were identified to be involved in 24 secondary metabolic pathways. 35 enzymes, which were encoded by 79 unigenes, were related to the biosynthesis of steroidal sapogenins in this transcriptome database, covering almost all the nodes in the steroidal pathway. The results of real-time PCR experiments on ten related transcripts (HMGR, MK, SQLE, FPPS, DXS, CAS, HMED, CYP51, DHCR7, and DHCR24 indicated that sapogenins were mainly biosynthesized by the mevalonate pathway. The expression of these ten transcripts in the tuber and leaves was found to be much higher than in the stem. Also, expression in the shoots was low. The nucleotide and protein sequences and conserved domains of four related genes (HMGR, CAS, SQS, and SMT1 were highly conserved between D. composita and D. zingiberensis; but expression of these four genes is greater in D. composita. However, there is no expression of these key enzymes in potato and no steroidal sapogenins are synthesized.

  11. Modulation of flavonoid biosynthetic pathway genes and anthocyanins due to virus infection in grapevine (Vitis vinifera L. leaves

    Directory of Open Access Journals (Sweden)

    Gutha Linga R

    2010-08-01

    Full Text Available Abstract Background Symptoms of grapevine leafroll disease (GLRD in red-fruited wine grape (Vitis vinifera L. cultivars consist of green veins and red and reddish-purple discoloration of inter-veinal areas of leaves. The reddish-purple color of symptomatic leaves may be due to the accumulation of anthocyanins and could reflect an up-regulation of genes involved in their biosynthesis. Results We examined six putative constitutively expressed genes, Ubiquitin, Actin, GAPDH, EF1-a, SAND and NAD5, for their potential as references for normalization of gene expression in reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR. Using the geNorm program, a combination of two genes (Actin and NAD5 was identified as the stable set of reference genes for normalization of gene expression data obtained from grapevine leaves. By using gene-specific RT-qPCR in combination with a reliable normalization factor, we compared relative expression of the flavonoid biosynthetic pathway genes between leaves infected with Grapevine leafroll-associated virus 3 (GLRaV-3 and exhibiting GLRD symptoms and virus-free green leaves obtained from a red-fruited wine grape cultivar (cv. Merlot. The expression levels of these different genes ranged from two- to fifty-fold increase in virus-infected leaves. Among them, CHS3, F3'5'H, F3H1, LDOX, LAR1 and MybA1 showed greater than 10-fold increase suggesting that they were expressed at significantly higher levels in virus-infected symptomatic leaves. HPLC profiling of anthocyanins extracted from leaves indicated the presence of cyanidin-3-glucoside and malvidin-3-glucoside only in virus-infected symptomatic leaves. The results also showed 24% higher levels of flavonols in virus-infected symptomatic leaves than in virus-free green leaves, with quercetin followed by myricetin being the predominant compounds. Proanthocyanidins, estimated as total tannins by protein precipitation method, were 36% higher in virus

  12. The heme biosynthetic pathway of the obligate Wolbachia endosymbiont of Brugia malayi as a potential anti-filarial drug target.

    Directory of Open Access Journals (Sweden)

    Bo Wu

    2009-07-01

    Full Text Available Filarial parasites (e.g., Brugia malayi, Onchocerca volvulus, and Wuchereria bancrofti are causative agents of lymphatic filariasis and onchocerciasis, which are among the most disabling of neglected tropical diseases. There is an urgent need to develop macro-filaricidal drugs, as current anti-filarial chemotherapy (e.g., diethylcarbamazine [DEC], ivermectin and albendazole can interrupt transmission predominantly by killing microfilariae (mf larvae, but is less effective on adult worms, which can live for decades in the human host. All medically relevant human filarial parasites appear to contain an obligate endosymbiotic bacterium, Wolbachia. This alpha-proteobacterial mutualist has been recognized as a potential target for filarial nematode life cycle intervention, as antibiotic treatments of filarial worms harboring Wolbachia result in the loss of worm fertility and viability upon antibiotic treatments both in vitro and in vivo. Human trials have confirmed this approach, although the length of treatments, high doses required and medical counter-indications for young children and pregnant women warrant the identification of additional anti-Wolbachia drugs.Genome sequence analysis indicated that enzymes involved in heme biosynthesis might constitute a potential anti-Wolbachia target set. We tested different heme biosynthetic pathway inhibitors in ex vivo B. malayi viability assays and report a specific effect of N-methyl mesoporphyrin (NMMP, which targets ferrochelatase (FC, the last step. Our phylogenetic analysis indicates evolutionarily significant divergence between Wolbachia heme genes and their human homologues. We therefore undertook the cloning, overexpression and analysis of several enzymes of this pathway alongside their human homologues, and prepared proteins for drug targeting. In vitro enzyme assays revealed a approximately 600-fold difference in drug sensitivities to succinyl acetone (SA between Wolbachia and human 5

  13. Regulation of the anthocyanin biosynthetic pathway by the TTG1/bHLH/Myb transcriptional complex in Arabidopsis seedlings.

    Science.gov (United States)

    Gonzalez, Antonio; Zhao, Mingzhe; Leavitt, John M; Lloyd, Alan M

    2008-03-01

    In all higher plants studied to date, the anthocyanin pigment pathway is regulated by a suite of transcription factors that include Myb, bHLH and WD-repeat proteins. However, in Arabidopsis thaliana, the Myb regulators remain to be conclusively identified, and little is known about anthocyanin pathway regulation by TTG1-dependent transcriptional complexes. Previous overexpression of the PAP1 Myb suggested that genes from the entire phenylpropanoid pathway are targets of regulation by Myb/bHLH/WD-repeat complexes in Arabidopsis, in contrast to other plants. Here we demonstrate that overexpression of Myb113 or Myb114 results in substantial increases in pigment production similar to those previously seen as a result of over-expression of PAP1, and pigment production in these overexpressors remains TTG1- and bHLH-dependent. Also, plants harboring an RNAi construct targeting PAP1 and three Myb candidates (PAP2, Myb113 and Myb114) showed downregulated Myb gene expression and obvious anthocyanin deficiencies. Correlated with these anthocyanin deficiencies is downregulation of the same late anthocyanin structural genes that are downregulated in ttg1 and bHLH anthocyanin mutants. Expression studies using GL3:GR and TTG1:GR fusions revealed direct regulation of the late biosynthetic genes only. Functional diversification between GL3 and EGL3 with regard to activation of gene targets was revealed by GL3:GR studies in single and double bHLH mutant seedlings. Expression profiles for Myb and bHLH regulators are also presented in the context of pigment production in young seedlings.

  14. Rational engineering of p-hydroxybenzoate hydroxylase to enable efficient gallic acid synthesis via a novel artificial biosynthetic pathway.

    Science.gov (United States)

    Chen, Zhenya; Shen, Xiaolin; Wang, Jian; Wang, Jia; Yuan, Qipeng; Yan, Yajun

    2017-11-01

    Gallic acid (GA) is a naturally occurring phytochemical that has strong antioxidant and antibacterial activities. It is also used as a potential platform chemical for the synthesis of diverse high-value compounds. Hydrolytic degradation of tannins by acids, bases or microorganisms serves as a major way for GA production, which however, might cause environmental pollution and low yield and efficiency. Here, we report a novel approach for efficient microbial production of GA. First, structure-based rational engineering of PobA, a p-hydroxybenzoate hydroxylase from Pseudomonas aeruginosa, generated a new mutant, Y385F/T294A PobA, which displayed much higher activity toward 3,4-dihydroxybenzoic acid (3,4-DHBA) than the wild-type and any other reported mutants. Remarkably, expression of this mutant in Escherichia coli enabled generation of 1149.59 mg/L GA from 1000 mg/L 4-hydroxybenzoic acid (4-HBA), representing a 93% molar conversion ratio. Based on that, we designed and reconstituted a novel artificial biosynthetic pathway of GA and achieved 440.53 mg/L GA production from simple carbon sources in E. coli. Further enhancement of precursor supply through reinforcing shikimate pathway was able to improve GA de novo production to 1266.39 mg/L in shake flasks. Overall, this study not only led to the development of a highly active PobA variant for hydroxylating 3,4-DHBA into GA via structure-based protein engineering approach, but also demonstrated a promising pathway for bio-based manufacturing of GA and its derived compounds. Biotechnol. Bioeng. 2017;114: 2571-2580. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  15. EPA, DHA, and Lipoic Acid Differentially Modulate the n-3 Fatty Acid Biosynthetic Pathway in Atlantic Salmon Hepatocytes.

    Science.gov (United States)

    Bou, Marta; Østbye, Tone-Kari; Berge, Gerd M; Ruyter, Bente

    2017-03-01

    The aim of the present study was to investigate how EPA, DHA, and lipoic acid (LA) influence the different metabolic steps in the n-3 fatty acid (FA) biosynthetic pathway in hepatocytes from Atlantic salmon fed four dietary levels (0, 0.5, 1.0 and 2.0%) of EPA, DHA or a 1:1 mixture of these FA. The hepatocytes were incubated with [1- 14 C] 18:3n-3 in the presence or absence of LA (0.2 mM). Increased endogenous levels of EPA and/or DHA and LA exposure both led to similar responses in cells with reduced desaturation and elongation of [1- 14 C] 18:3n-3 to 18:4n-3, 20:4n-3, and EPA, in agreement with reduced expression of the Δ6 desaturase gene involved in the first step of conversion. DHA production, on the other hand, was maintained even in groups with high endogenous levels of DHA, possibly due to a more complex regulation of this last step in the n-3 metabolic pathway. Inhibition of the Δ6 desaturase pathway led to increased direct elongation to 20:3n-3 by both DHA and LA. Possibly the route by 20:3n-3 and then Δ8 desaturation to 20:4n-3, bypassing the first Δ6 desaturase step, can partly explain the maintained or even increased levels of DHA production. LA increased DHA production in the phospholipid fraction of hepatocytes isolated from fish fed 0 and 0.5% EPA and/or DHA, indicating that LA has the potential to further increase the production of this health-beneficial FA in fish fed diets with low levels of EPA and/or DHA.

  16. Giant virus Megavirus chilensis encodes the biosynthetic pathway for uncommon acetamido sugars.

    Science.gov (United States)

    Piacente, Francesco; De Castro, Cristina; Jeudy, Sandra; Molinaro, Antonio; Salis, Annalisa; Damonte, Gianluca; Bernardi, Cinzia; Abergel, Chantal; Tonetti, Michela G

    2014-08-29

    Giant viruses mimicking microbes, by the sizes of their particles and the heavily glycosylated fibrils surrounding their capsids, infect Acanthamoeba sp., which are ubiquitous unicellular eukaryotes. The glycans on fibrils are produced by virally encoded enzymes, organized in gene clusters. Like Mimivirus, Megavirus glycans are mainly composed of virally synthesized N-acetylglucosamine (GlcNAc). They also contain N-acetylrhamnosamine (RhaNAc), a rare sugar; the enzymes involved in its synthesis are encoded by a gene cluster specific to Megavirus close relatives. We combined activity assays on two enzymes of the pathway with mass spectrometry and NMR studies to characterize their specificities. Mg534 is a 4,6-dehydratase 5-epimerase; its three-dimensional structure suggests that it belongs to a third subfamily of inverting dehydratases. Mg535, next in the pathway, is a bifunctional 3-epimerase 4-reductase. The sequential activity of the two enzymes leads to the formation of UDP-l-RhaNAc. This study is another example of giant viruses performing their glycan synthesis using enzymes different from their cellular counterparts, raising again the question of the origin of these pathways. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Functional analysis of aromatic biosynthetic pathways in Pseudomonas putida KT2440

    Science.gov (United States)

    Molina‐Henares, M. Antonia; García‐Salamanca, Adela; Molina‐Henares, A. Jesús; De La Torre, Jesús; Herrera, M. Carmen; Ramos, Juan L.; Duque, Estrella

    2009-01-01

    Summary Pseudomonas putida KT2440 is a non‐pathogenic prototrophic bacterium with high potential for biotechnological applications. Despite all that is known about this strain, the biosynthesis of essential chemicals has not been fully analysed and auxotroph mutants are scarce. We carried out massive mini‐Tn5 random mutagenesis and screened for auxotrophs that require aromatic amino acids. The biosynthesis of aromatic amino acids was analysed in detail including physical and transcriptional organization of genes, complementation assays and feeding experiments to establish pathway intermediates. There is a single pathway from chorismate leading to the biosynthesis of tryptophan, whereas the biosynthesis of phenylalanine and tyrosine is achieved through multiple convergent pathways. Genes for tryptophan biosynthesis are grouped in unlinked regions with the trpBA and trpGDE genes organized as operons and the trpI, trpE and trpF genes organized as single transcriptional units. The pheA and tyrA gene‐encoding multifunctional enzymes for phenylalanine and tyrosine biosynthesis are linked in the chromosome and form an operon with the serC gene involved in serine biosynthesis. The last step in the biosynthesis of these two amino acids requires an amino transferase activity for which multiple tyrB‐like genes are present in the host chromosome. PMID:21261884

  18. Deciphering the sugar biosynthetic pathway and tailoring steps of nucleoside antibiotic A201A unveils a GDP-l-galactose mutase.

    Science.gov (United States)

    Zhu, Qinghua; Chen, Qi; Song, Yongxiang; Huang, Hongbo; Li, Jun; Ma, Junying; Li, Qinglian; Ju, Jianhua

    2017-05-09

    Galactose, a monosaccharide capable of assuming two possible configurational isomers (d-/l-), can exist as a six-membered ring, galactopyranose (Gal p ), or as a five-membered ring, galactofuranose (Gal f ). UDP-galactopyranose mutase (UGM) mediates the conversion of pyranose to furanose thereby providing a precursor for d-Gal f Moreover, UGM is critical to the virulence of numerous eukaryotic and prokaryotic human pathogens and thus represents an excellent antimicrobial drug target. However, the biosynthetic mechanism and relevant enzymes that drive l-Gal f production have not yet been characterized. Herein we report that efforts to decipher the sugar biosynthetic pathway and tailoring steps en route to nucleoside antibiotic A201A led to the discovery of a GDP-l-galactose mutase, MtdL. Systematic inactivation of 18 of the 33 biosynthetic genes in the A201A cluster and elucidation of 10 congeners, coupled with feeding and in vitro biochemical experiments, enabled us to: ( i ) decipher the unique enzyme, GDP-l-galactose mutase associated with production of two unique d-mannose-derived sugars, and ( ii ) assign two glycosyltransferases, four methyltransferases, and one desaturase that regiospecifically tailor the A201A scaffold and display relaxed substrate specificities. Taken together, these data provide important insight into the origin of l-Gal f -containing natural product biosynthetic pathways with likely ramifications in other organisms and possible antimicrobial drug targeting strategies.

  19. Selectively improving nikkomycin Z production by blocking the imidazolone biosynthetic pathway of nikkomycin X and uracil feeding in Streptomyces ansochromogenes

    Directory of Open Access Journals (Sweden)

    Yang Haihua

    2009-11-01

    Full Text Available Abstract Background Nikkomycins are a group of peptidyl nucleoside antibiotics and act as potent inhibitors of chitin synthases in fungi and insects. Nikkomycin X and Z are the main components produced by Streptomyces ansochromogenes. Of them, nikkomycin Z is a promising antifungal agent with clinical significance. Since highly structural similarities between nikkomycin Z and X, separation of nikkomycin Z from the culture medium of S. ansochromogenes is difficult. Thus, generating a nikkomycin Z selectively producing strain is vital to scale up the nikkomycin Z yields for clinical trials. Results A nikkomycin Z producing strain (sanPDM was constructed by blocking the imidazolone biosynthetic pathway of nikkomycin X via genetic manipulation and yielded 300 mg/L nikkomycin Z and abolished the nikkomycin X production. To further increase the yield of nikkomycin Z, the effects of different precursors on its production were investigated. Precursors of nucleoside moiety (uracil or uridine had a stimulatory effect on nikkomycin Z production while precursors of peptidyl moiety (L-lysine and L-glutamate had no effect. sanPDM produced the maximum yields of nikkomycin Z (800 mg/L in the presence of uracil at the concentration of 2 g/L and it was approximately 2.6-fold higher than that of the parent strain. Conclusion A high nikkomycin Z selectively producing was obtained by genetic manipulation combined with precursors feeding. The strategy presented here might be applicable in other bacteria to selectively produce targeted antibiotics.

  20. Genome Engineering of the 2,3-Butanediol Biosynthetic Pathway for Tight Regulation in Cyanobacteria.

    Science.gov (United States)

    Nozzi, Nicole E; Atsumi, Shota

    2015-11-20

    Cyanobacteria have gained popularity among the metabolic engineering community as a tractable photosynthetic host for renewable chemical production. However, though a number of successfully engineered production systems have been reported, long-term genetic stability remains an issue for cyanobacterial systems. The genetic engineering toolbox for cyanobacteria is largely lacking inducible systems for expression control. The characterization of tight regulation systems for use in cyanobacteria may help to alleviate this problem. In this work we explore the function of the IPTG inducible promoter P(L)lacO1 in the model cyanobacterium Synechococcus elongatus PCC 7942 as well as the effect of gene order within an operon on pathway expression. According to our experiments, P(L)lacO1 functions well as an inducible promoter in S. elongatus. Additionally, we found that gene order within an operon can strongly influence control of expression of each gene.

  1. Arctic mustard flower color polymorphism controlled by petal-specific downregulation at the threshold of the anthocyanin biosynthetic pathway.

    Directory of Open Access Journals (Sweden)

    Cynthia A Dick

    2011-04-01

    Full Text Available Intra- and interspecific variation in flower color is a hallmark of angiosperm diversity. The evolutionary forces underlying the variety of flower colors can be nearly as diverse as the colors themselves. In addition to pollinator preferences, non-pollinator agents of selection can have a major influence on the evolution of flower color polymorphisms, especially when the pigments in question are also expressed in vegetative tissues. In such cases, identifying the target(s of selection starts with determining the biochemical and molecular basis for the flower color variation and examining any pleiotropic effects manifested in vegetative tissues. Herein, we describe a widespread purple-white flower color polymorphism in the mustard Parrya nudicaulis spanning Alaska. The frequency of white-flowered individuals increases with increasing growing-season temperature, consistent with the role of anthocyanin pigments in stress tolerance. White petals fail to produce the stress responsive flavonoid intermediates in the anthocyanin biosynthetic pathway (ABP, suggesting an early pathway blockage. Petal cDNA sequences did not reveal blockages in any of the eight enzyme-coding genes in white-flowered individuals, nor any color differentiating SNPs. A qRT-PCR analysis of white petals identified a 24-fold reduction in chalcone synthase (CHS at the threshold of the ABP, but no change in CHS expression in leaves and sepals. This arctic species has avoided the deleterious effects associated with the loss of flavonoid intermediates in vegetative tissues by decoupling CHS expression in petals and leaves, yet the correlation of flower color and climate suggests that the loss of flavonoids in the petals alone may affect the tolerance of white-flowered individuals to colder environments.

  2. tRNA-dependent cysteine biosynthetic pathway represents a strategy to increase cysteine contents by preventing it from thermal degradation: thermal adaptation of methanogenic archaea ancestor.

    Science.gov (United States)

    Qu, Ge; Wang, Wei; Chen, Ling-Ling; Qian, Shao-Song; Zhang, Hong-Yu

    2009-10-01

    Although cysteine (Cys) is beneficial to stabilize protein structures, it is not prevalent in thermophiles. For instance, the Cys contents in most thermophilic archaea are only around 0.7%. However, methanogenic archaea, no matter thermophilic or not, contain relatively abundant Cys, which remains elusive for a long time. Recently, Klipcan et al. correlated this intriguing property of methanogenic archaea with their unique tRNA-dependent Cys biosynthetic pathway. But, the deep reasons underlying the correlation are ambiguous. Considering the facts that free Cys is thermally labile and the tRNA-dependent Cys biosynthesis avoids the use of free Cys, we speculate that the unique Cys biosynthetic pathway represents a strategy to increase Cys contents by preventing it from thermal degradation, which may be relevant to the thermal adaptation of methanogenic archaea ancestor.

  3. Novel acetylcholinesterase inhibitors from Zijuan tea and biosynthetic pathway of caffeoylated catechin in tea plant.

    Science.gov (United States)

    Wang, Wei; Fu, Xi-Wen; Dai, Xin-Long; Hua, Fang; Chu, Gang-Xiu; Chu, Ming-Jie; Hu, Feng-Lin; Ling, Tie-Jun; Gao, Li-Ping; Xie, Zhong-Wen; Wan, Xiao-Chun; Bao, Guan-Hu

    2017-12-15

    Zijuan tea is a special cultivar of Yunnan broad-leaf tea (Camellia sinensis var. assamica) with purple buds, leaves, and stems. Phytochemical study on this tea led to the discovery of three hydroxycinnamoylated catechins (HCCs) (1-3), seven other catechins (4-10), three proanthocyanidins (11-13), five flavones and flavone glycosides (14-18), two alkaloids (19, 20), one steroid (21), and one phenylpropanoid glycoside (22). The isolation and structural elucidation of the caffeoylated catechin (1) by means of spectroscopic techniques were described. We also provide the first evidence that 1 is synthesized via a two-step pathway in tea plant. The three HCCs (1-3) were investigated on their bioactivity through molecular modeling simulation and biochemical experiments. Our results show that they bind acetylcholinesterase (AChE) tightly and have strong AChE inhibitory activity with IC 50 value at 2.49, 11.41, 62.26μM, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Molecular characterization and functional analysis of chalcone synthase from Syringa oblata Lindl. in the flavonoid biosynthetic pathway.

    Science.gov (United States)

    Wang, Yu; Dou, Ying; Wang, Rui; Guan, Xuelian; Hu, Zenghui; Zheng, Jian

    2017-11-30

    The flower color of Syringa oblata Lindl., which is often modulated by the flavonoid content, varies and is an important ornamental feature. Chalcone synthase (CHS) catalyzes the first key step in the flavonoid biosynthetic pathway. However, little is known about the role of S. oblata CHS (SoCHS) in flavonoid biosynthesis in this species. Here, we isolate and analyze the cDNA (SoCHS1) that encodes CHS in S. oblata. We also sought to analyzed the molecular characteristics and function of flavonoid metabolism by SoCHS1. We successfully isolated the CHS-encoding genomic DNA (gDNA) in S. oblata (SoCHS1), and the gene structural analysis indicated it had no intron. The opening reading frame (ORF) sequence of SoCHS1 was 1170bp long and encoded a 389-amino acid polypeptide. Multiple sequence alignment revealed that both the conserved CHS active site residues and CHS signature sequence were in the deduced amino acid sequence of SoCHS1. Crystallographic analysis revealed that the protein structure of SoCHS1 is highly similar to that of FnCHS1 in Freesia hybrida. The quantitative real-time polymerase chain reaction (PCR) performed to detect the SoCHS1 transcript expression levels in flowers, and other tissues revealed the expression was significantly correlated with anthocyanin accumulation during flower development. The ectopic expression results of Nicotiana tabacum showed that SoCHS1 overexpression in transgenic tobacco changed the flower color from pale pink to pink. In conclusion, these results suggest that SoCHS1 plays an essential role in flavonoid biosynthesis in S. oblata, and could be used to modify flavonoid components in other plant species. Copyright © 2017. Published by Elsevier B.V.

  5. An R2R3 MYB transcription factor associated with regulation of the anthocyanin biosynthetic pathway in Rosaceae.

    Science.gov (United States)

    Lin-Wang, Kui; Bolitho, Karen; Grafton, Karryn; Kortstee, Anne; Karunairetnam, Sakuntala; McGhie, Tony K; Espley, Richard V; Hellens, Roger P; Allan, Andrew C

    2010-03-21

    The control of plant anthocyanin accumulation is via transcriptional regulation of the genes encoding the biosynthetic enzymes. A key activator appears to be an R2R3 MYB transcription factor. In apple fruit, skin anthocyanin levels are controlled by a gene called MYBA or MYB1, while the gene determining fruit flesh and foliage anthocyanin has been termed MYB10. In order to further understand tissue-specific anthocyanin regulation we have isolated orthologous MYB genes from all the commercially important rosaceous species. We use gene specific primers to show that the three MYB activators of apple anthocyanin (MYB10/MYB1/MYBA) are likely alleles of each other. MYB transcription factors, with high sequence identity to the apple gene were isolated from across the rosaceous family (e.g. apples, pears, plums, cherries, peaches, raspberries, rose, strawberry). Key identifying amino acid residues were found in both the DNA-binding and C-terminal domains of these MYBs. The expression of these MYB10 genes correlates with fruit and flower anthocyanin levels. Their function was tested in tobacco and strawberry. In tobacco, these MYBs were shown to induce the anthocyanin pathway when co-expressed with bHLHs, while over-expression of strawberry and apple genes in the crop of origin elevates anthocyanins. This family-wide study of rosaceous R2R3 MYBs provides insight into the evolution of this plant trait. It has implications for the development of new coloured fruit and flowers, as well as aiding the understanding of temporal-spatial colour change.

  6. An R2R3 MYB transcription factor associated with regulation of the anthocyanin biosynthetic pathway in Rosaceae

    Directory of Open Access Journals (Sweden)

    McGhie Tony K

    2010-03-01

    Full Text Available Abstract Background The control of plant anthocyanin accumulation is via transcriptional regulation of the genes encoding the biosynthetic enzymes. A key activator appears to be an R2R3 MYB transcription factor. In apple fruit, skin anthocyanin levels are controlled by a gene called MYBA or MYB1, while the gene determining fruit flesh and foliage anthocyanin has been termed MYB10. In order to further understand tissue-specific anthocyanin regulation we have isolated orthologous MYB genes from all the commercially important rosaceous species. Results We use gene specific primers to show that the three MYB activators of apple anthocyanin (MYB10/MYB1/MYBA are likely alleles of each other. MYB transcription factors, with high sequence identity to the apple gene were isolated from across the rosaceous family (e.g. apples, pears, plums, cherries, peaches, raspberries, rose, strawberry. Key identifying amino acid residues were found in both the DNA-binding and C-terminal domains of these MYBs. The expression of these MYB10 genes correlates with fruit and flower anthocyanin levels. Their function was tested in tobacco and strawberry. In tobacco, these MYBs were shown to induce the anthocyanin pathway when co-expressed with bHLHs, while over-expression of strawberry and apple genes in the crop of origin elevates anthocyanins. Conclusions This family-wide study of rosaceous R2R3 MYBs provides insight into the evolution of this plant trait. It has implications for the development of new coloured fruit and flowers, as well as aiding the understanding of temporal-spatial colour change.

  7. The Distribution of Coumarins and Furanocoumarins in Citrus Species Closely Matches Citrus Phylogeny and Reflects the Organization of Biosynthetic Pathways.

    Directory of Open Access Journals (Sweden)

    Audray Dugrand-Judek

    Full Text Available Citrus plants are able to produce defense compounds such as coumarins and furanocoumarins to cope with herbivorous insects and pathogens. In humans, these chemical compounds are strong photosensitizers and can interact with medications, leading to the "grapefruit juice effect". Removing coumarins and furanocoumarins from food and cosmetics imply additional costs and might alter product quality. Thus, the selection of Citrus cultivars displaying low coumarin and furanocoumarin contents constitutes a valuable alternative. In this study, we performed ultra-performance liquid chromatography coupled with mass spectrometry analyses to determine the contents of these compounds within the peel and the pulp of 61 Citrus species representative of the genetic diversity all Citrus. Generally, Citrus peel contains larger diversity and higher concentrations of coumarin/furanocoumarin than the pulp of the same fruits. According to the chemotypes found in the peel, Citrus species can be separated into 4 groups that correspond to the 4 ancestral taxa (pummelos, mandarins, citrons and papedas and extended with their respective secondary species descendants. Three of the 4 ancestral taxa (pummelos, citrons and papedas synthesize high amounts of these compounds, whereas mandarins appear practically devoid of them. Additionally, all ancestral taxa and their hybrids are logically organized according to the coumarin and furanocoumarin pathways described in the literature. This organization allows hypotheses to be drawn regarding the biosynthetic origin of compounds for which the biogenesis remains unresolved. Determining coumarin and furanocoumarin contents is also helpful for hypothesizing the origin of Citrus species for which the phylogeny is presently not firmly established. Finally, this work also notes favorable hybridization schemes that will lead to low coumarin and furanocoumarin contents, and we propose to select mandarins and Ichang papeda as Citrus

  8. Molecular interaction of the first 3 enzymes of the de novo pyrimidine biosynthetic pathway of Trypanosoma cruzi

    International Nuclear Information System (INIS)

    Nara, Takeshi; Hashimoto, Muneaki; Hirawake, Hiroko; Liao, Chien-Wei; Fukai, Yoshihisa; Suzuki, Shigeo; Tsubouchi, Akiko; Morales, Jorge; Takamiya, Shinzaburo; Fujimura, Tsutomu; Taka, Hikari; Mineki, Reiko; Fan, Chia-Kwung; Inaoka, Daniel Ken; Inoue, Masayuki; Tanaka, Akiko; Harada, Shigeharu; Kita, Kiyoshi

    2012-01-01

    Highlights: ► An Escherichia coli strain co-expressing CPSII, ATC, and DHO of Trypanosoma cruzi was constructed. ► Molecular interactions between CPSII, ATC, and DHO of T. cruzi were demonstrated. ► CPSII bound with both ATC and DHO. ► ATC bound with both CPSII and DHO. ► A functional tri-enzyme complex might precede the establishment of the fused enzyme. -- Abstract: The first 3 reaction steps of the de novo pyrimidine biosynthetic pathway are catalyzed by carbamoyl-phosphate synthetase II (CPSII), aspartate transcarbamoylase (ATC), and dihydroorotase (DHO), respectively. In eukaryotes, these enzymes are structurally classified into 2 types: (1) a CPSII-DHO-ATC fusion enzyme (CAD) found in animals, fungi, and amoebozoa, and (2) stand-alone enzymes found in plants and the protist groups. In the present study, we demonstrate direct intermolecular interactions between CPSII, ATC, and DHO of the parasitic protist Trypanosoma cruzi, which is the causative agent of Chagas disease. The 3 enzymes were expressed in a bacterial expression system and their interactions were examined. Immunoprecipitation using an antibody specific for each enzyme coupled with Western blotting-based detection using antibodies for the counterpart enzymes showed co-precipitation of all 3 enzymes. From an evolutionary viewpoint, the formation of a functional tri-enzyme complex may have preceded—and led to—gene fusion to produce the CAD protein. This is the first report to demonstrate the structural basis of these 3 enzymes as a model of CAD. Moreover, in conjunction with the essentiality of de novo pyrimidine biosynthesis in the parasite, our findings provide a rationale for new strategies for developing drugs for Chagas disease, which target the intermolecular interactions of these 3 enzymes.

  9. Biosynthetic Studies of 13-Desmethylspirolide C Produced by Alexandrium ostenfeldii (= A. peruvianum): Rationalization of the Biosynthetic Pathway Following Incorporation of (13)C-Labeled Methionine and Application of the Odd-Even Rule of Methylation.

    Science.gov (United States)

    Anttila, Matthew; Strangman, Wendy; York, Robert; Tomas, Carmelo; Wright, Jeffrey L C

    2016-03-25

    Understanding the biosynthesis of dinoflagellate polyketides presents many unique challenges. Because of the remaining hurdles to dinoflagellate genome sequencing, precursor labeling studies remain the only viable way to investigate dinoflagellate biosynthesis. However, prior studies have shown that polyketide chain assembly does not follow any of the established processes. Additionally, acetate, the common precursor for polyketides, is frequently scrambled, thus compromising interpretation. These factors are further compounded by low production yields of the compounds of interest. A recent report on the biosynthesis of spirolides, a group belonging to the growing class of toxic spiroimines, provided some insight into the polyketide assembly process based on acetate labeling studies, but many details were left uncertain. By feeding (13)C methyl-labeled methionine to cultures of Alexandrium ostenfeldii, the producing organism of 13-desmethylspirolide C, and application of the odd-even methylation rule, the complete biosynthetic pathway has been established.

  10. Production of Odd-Carbon Dicarboxylic Acids in Escherichia coli Using an Engineered Biotin–Fatty Acid Biosynthetic Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Haushalter, Robert W. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Bioscience Division; Phelan, Ryan M. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Bioscience Division; Hoh, Kristina M. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Bioscience Division; Su, Cindy [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Bioscience Division; Wang, George [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Bioscience Division; Baidoo, Edward E. K. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Bioscience Division; Keasling, Jay D. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Physical Bioscience Division

    2017-03-14

    Dicarboxylic acids are commodity chemicals used in the production of plastics, polyesters, nylons, fragrances, and medications. Bio-based routes to dicarboxylic acids are gaining attention due to environmental concerns about petroleum-based production of these compounds. Some industrial applications require dicarboxylic acids with specific carbon chain lengths, including odd-carbon species. Biosynthetic pathways involving cytochrome P450-catalyzed oxidation of fatty acids in yeast and bacteria have been reported, but these systems produce almost exclusively even-carbon species. Here in this paper we report a novel pathway to odd-carbon dicarboxylic acids directly from glucose in Escherichia coli by employing an engineered pathway combining enzymes from biotin and fatty acid synthesis. Optimization of the pathway will lead to industrial strains for the production of valuable odd-carbon diacids.

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

    Science.gov (United States)

    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. © 2015 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The

  12. An R2R3 MYB transcription factor associated with regulation of the anthocyanin biosynthetic pathway in Rosaceae (on linr)

    NARCIS (Netherlands)

    Wang, Kui-Lin; Bolitho, Karen; Grafton, Karryn; Kortstee, A.J.; Karunairetnam, Sakuntala; McGhie, T.K.; Espley, R.V.; Hellens, R.P.; Allan, A.C.

    2010-01-01

    Background - The control of plant anthocyanin accumulation is via transcriptional regulation of the genes encoding the biosynthetic enzymes. A key activator appears to be an R2R3 MYB transcription factor. In apple fruit, skin anthocyanin levels are controlled by a gene called MYBA or MYB1, while the

  13. Laccase-catalysed oxidations of naturally occurring phenols: from in vivo biosynthetic pathways to green synthetic applications

    Czech Academy of Sciences Publication Activity Database

    Jong-Rok, J.; Baldrian, Petr; Murugesan, K.; Chang, Y.-S.

    2012-01-01

    Roč. 5, č. 3 (2012), s. 318-332 ISSN 1751-7907 Institutional research plan: CEZ:AV0Z50200510 Keywords : POLYCYCLIC AROMATIC-HYDROCARBONS * CRYPTOCOCCUS-NEOFORMANS * LIGNIN BIOSYNTHESIS Subject RIV: EE - Microbiology, Virology Impact factor: 3.214, year: 2012

  14. An R2R3 MYB transcription factor associated with regulation of the anthocyanin biosynthetic pathway in Rosaceae (on linr)

    OpenAIRE

    Wang, Kui-Lin; Bolitho, Karen; Grafton, Karryn; Kortstee, A.J.; Karunairetnam, Sakuntala; McGhie, T.K.; Espley, R.V.; Hellens, R.P.; Allan, A.C.

    2010-01-01

    Background - The control of plant anthocyanin accumulation is via transcriptional regulation of the genes encoding the biosynthetic enzymes. A key activator appears to be an R2R3 MYB transcription factor. In apple fruit, skin anthocyanin levels are controlled by a gene called MYBA or MYB1, while the gene determining fruit flesh and foliage anthocyanin has been termed MYB10. In order to further understand tissue-specific anthocyanin regulation we have isolated orthologous MYB genes from all th...

  15. Biosynthetic pathway for γ-cyclic sarcinaxanthin in Micrococcus luteus: heterologous expression and evidence for diverse and multiple catalytic functions of C(50) carotenoid cyclases.

    Science.gov (United States)

    Netzer, Roman; Stafsnes, Marit H; Andreassen, Trygve; Goksøyr, Audun; Bruheim, Per; Brautaset, Trygve

    2010-11-01

    We report the cloning and characterization of the biosynthetic gene cluster (crtE, crtB, crtI, crtE2, crtYg, crtYh, and crtX) of the γ-cyclic C(50) carotenoid sarcinaxanthin in Micrococcus luteus NCTC2665. Expression of the complete and partial gene cluster in Escherichia coli hosts revealed that sarcinaxanthin biosynthesis from the precursor molecule farnesyl pyrophosphate (FPP) proceeds via C(40) lycopene, C(45) nonaflavuxanthin, C(50) flavuxanthin, and C(50) sarcinaxanthin. Glucosylation of sarcinaxanthin was accomplished by the crtX gene product. This is the first report describing the biosynthetic pathway of a γ-cyclic C(50) carotenoid. Expression of the corresponding genes from the marine M. luteus isolate Otnes7 in a lycopene-producing E. coli host resulted in the production of up to 2.5 mg/g cell dry weight sarcinaxanthin in shake flasks. In an attempt to experimentally understand the specific difference between the biosynthetic pathways of sarcinaxanthin and the structurally related ε-cyclic decaprenoxanthin, we constructed a hybrid gene cluster with the γ-cyclic C(50) carotenoid cyclase genes crtYg and crtYh from M. luteus replaced with the analogous ε-cyclic C(50) carotenoid cyclase genes crtYe and crtYf from the natural decaprenoxanthin producer Corynebacterium glutamicum. Surprisingly, expression of this hybrid gene cluster in an E. coli host resulted in accumulation of not only decaprenoxanthin, but also sarcinaxanthin and the asymmetric ε- and γ-cyclic C(50) carotenoid sarprenoxanthin, described for the first time in this work. Together, these data contributed to new insight into the diverse and multiple functions of bacterial C(50) carotenoid cyclases as key catalysts for the synthesis of structurally different carotenoids.

  16. Functional analysis of metabolic channeling and regulation in lignin biosynthesis: a computational approach.

    Directory of Open Access Journals (Sweden)

    Yun Lee

    Full Text Available Lignin is a polymer in secondary cell walls of plants that is known to have negative impacts on forage digestibility, pulping efficiency, and sugar release from cellulosic biomass. While targeted modifications of different lignin biosynthetic enzymes have permitted the generation of transgenic plants with desirable traits, such as improved digestibility or reduced recalcitrance to saccharification, some of the engineered plants exhibit monomer compositions that are clearly at odds with the expected outcomes when the biosynthetic pathway is perturbed. In Medicago, such discrepancies were partly reconciled by the recent finding that certain biosynthetic enzymes may be spatially organized into two independent channels for the synthesis of guaiacyl (G and syringyl (S lignin monomers. Nevertheless, the mechanistic details, as well as the biological function of these interactions, remain unclear. To decipher the working principles of this and similar control mechanisms, we propose and employ here a novel computational approach that permits an expedient and exhaustive assessment of hundreds of minimal designs that could arise in vivo. Interestingly, this comparative analysis not only helps distinguish two most parsimonious mechanisms of crosstalk between the two channels by formulating a targeted and readily testable hypothesis, but also suggests that the G lignin-specific channel is more important for proper functioning than the S lignin-specific channel. While the proposed strategy of analysis in this article is tightly focused on lignin synthesis, it is likely to be of similar utility in extracting unbiased information in a variety of situations, where the spatial organization of molecular components is critical for coordinating the flow of cellular information, and where initially various control designs seem equally valid.

  17. Large-Scale Transcriptome Analysis of Two Sugarcane Genotypes Contrasting for Lignin Content.

    Directory of Open Access Journals (Sweden)

    Renato Vicentini

    Full Text Available Sugarcane is an important crop worldwide for sugar and first generation ethanol production. Recently, the residue of sugarcane mills, named bagasse, has been considered a promising lignocellulosic biomass to produce the second-generation ethanol. Lignin is a major factor limiting the use of bagasse and other plant lignocellulosic materials to produce second-generation ethanol. Lignin biosynthesis pathway is a complex network and changes in the expression of genes of this pathway have in general led to diverse and undesirable impacts on plant structure and physiology. Despite its economic importance, sugarcane genome was still not sequenced. In this study a high-throughput transcriptome evaluation of two sugarcane genotypes contrasting for lignin content was carried out. We generated a set of 85,151 transcripts of sugarcane using RNA-seq and de novo assembling. More than 2,000 transcripts showed differential expression between the genotypes, including several genes involved in the lignin biosynthetic pathway. This information can give valuable knowledge on the lignin biosynthesis and its interactions with other metabolic pathways in the complex sugarcane genome.

  18. Exploring bacterial lignin degradation.

    Science.gov (United States)

    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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. A novel multifunctional O-methyltransferase implicated in a dual methylation pathway associated with lignin biosynthesis in loblolly pine

    OpenAIRE

    Li, Laigeng; Popko, Jacqueline L.; Zhang, Xing-Hai; Osakabe, Keishi; Tsai, Chung-Jui; Joshi, Chandrashekhar P.; Chiang, Vincent L.

    1997-01-01

    S-adenosyl-l-methionine (SAM)-dependent O-methyltransferases (OMTs) catalyze the methylation of hydroxycinnamic acid derivatives for the synthesis of methylated plant polyphenolics, including lignin. The distinction in the extent of methylation of lignins in angiosperms and gymnosperms, mediated by substrate-specific OMTs, represents one of the fundamental differences in lignin biosynthesis between these two classes of plants. In angiosperms, two types of structurally and functionally distinc...

  20. A R2R3-MYB transcription factor regulates the flavonol biosynthetic pathway in a traditional Chinese medicinal plant, Epimedium sagittatum

    Directory of Open Access Journals (Sweden)

    Wenjun Huang

    2016-07-01

    Full Text Available Flavonols as plant secondary metabolites with vital roles in plant development and defense against UV light, have been demonstrated to be the main bioactive components in the genus Epimedium plants, several species of which are used as materials for Herba Epimedii, an important traditional Chinese medicine. The flavonol biosynthetic pathway genes had been already isolated from E. sagittatum, but a R2R3-MYB transcription factor regulating the flavonol synthesis has not been functionally characterized so far in Epimedium plants. In this study, we isolated and characterized the R2R3-MYB transcription factor EsMYBF1 involved in regulation of the flavonol biosynthetic pathway from E. sagittatum. Sequence analysis indicated that EsMYBF1 belongs to the subgroup 7 of R2R3-MYB family which contains the flavonol-specific MYB regulators identified to date. Transient reporter assay showed that EsMYBF1 strongly activated the promoters of EsF3H (flavanone 3-hydroxylase and EsFLS (flavonol synthase, but not the promoters of EsDFRs (dihydroflavonol 4-reductase and EsANS (anthocyanidin synthase in transiently transformed Nicotiana benthamiana leaves. Both yeast two-hybrid assay and transient reporter assay validated EsMYBF1 to be independent of EsTT8, or AtTT8 bHLH regulators of the flavonoid pathway as cofactors. Ectopic expression of EsMYBF1 in transgenic tobacco resulted in the increased flavonol content and the decreased anthocyanin content in flowers. Correspondingly, the structural genes involved in flavonol synthesis were upregulated in the EsMYBF1 overexpression lines, including NtCHS (chalcone synthase, NtCHI (chalcone isomerase, NtF3H and NtFLS, whereas the late biosynthetic genes of the anthocyanin pathway (NtDFR and NtANS were remarkably downregulated, compared to the controls. These results suggest that EsMYBF1 is a flavonol-specific R2R3-MYB regulator, and involved in regulation of the biosynthesis of the flavonol-derived bioactive components in E

  1. NMR characterization of altered lignins extracted from tobacco plants down-regulated for lignification enzymes cinnamylalcohol dehydrogenase and cinnamoyl-CoA reductase.

    Science.gov (United States)

    Ralph, J; Hatfield, R D; Piquemal, J; Yahiaoui, N; Pean, M; Lapierre, C; Boudet, A M

    1998-10-27

    Homologous antisense constructs were used to down-regulate tobacco cinnamyl-alcohol dehydrogenase (CAD; EC 1.1.1.195) and cinnamoyl-CoA reductase (CCR; EC 1.2.1.44) activities in the lignin monomer biosynthetic pathway. CCR converts activated cinnamic acids (hydroxycinnamoyl-SCoAs) to cinnamaldehydes; cinnamaldehydes are then reduced to cinnamyl alcohols by CAD. The transformations caused the incorporation of nontraditional components into the extractable tobacco lignins, as evidenced by NMR. Isolated lignin of antisense-CAD tobacco contained fewer coniferyl and sinapyl alcohol-derived units that were compensated for by elevated levels of benzaldehydes and cinnamaldehydes. Products from radical coupling of cinnamaldehydes, particularly sinapaldehyde, which were barely discernible in normal tobacco, were major components of the antisense-CAD tobacco lignin. Lignin content was reduced in antisense-CCR tobacco, which displayed a markedly reduced vigor. That lignin contained fewer coniferyl alcohol-derived units and significant levels of tyramine ferulate. Tyramine ferulate is a sink for the anticipated build-up of feruloyl-SCoA, and may be up-regulated in response to a deficit of coniferyl alcohol. Although it is not yet clear whether the modified lignins are true structural components of the cell wall, the findings provide further indications of the metabolic plasticity of plant lignification. An ability to produce lignin from alternative monomers would open new avenues for manipulation of lignin by genetic biotechnologies.

  2. A novel mechanism of sulfur transfer catalyzed by O-acetylhomoserine sulfhydrylase in the methionine-biosynthetic pathway of Wolinella succinogenes

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Timothy H. [Cornell University, Ithaca, New York 14853-1301 (United States); Krishnamoorthy, Kalyanaraman; Begley, Tadhg P., E-mail: begley@tamu.edu [Texas A& M University, College Station, TX 77842 (United States); Ealick, Steven E., E-mail: begley@tamu.edu [Cornell University, Ithaca, New York 14853-1301 (United States)

    2011-10-01

    MetY is the first reported structure of an O-acetylhomoserine sulfhydrylase that utilizes a protein thiocarboxylate intermediate as the sulfur source in a novel methionine-biosynthetic pathway instead of catalyzing a direct sulfhydrylation reaction. O-Acetylhomoserine sulfhydrylase (OAHS) is a pyridoxal 5′-phosphate (PLP) dependent sulfide-utilizing enzyme in the l-cysteine and l-methionine biosynthetic pathways of various enteric bacteria and fungi. OAHS catalyzes the conversion of O-acetylhomoserine to homocysteine using sulfide in a process known as direct sulfhydrylation. However, the source of the sulfur has not been identified and no structures of OAHS have been reported in the literature. Here, the crystal structure of Wolinella succinogenes OAHS (MetY) determined at 2.2 Å resolution is reported. MetY crystallized in space group C2 with two monomers in the asymmetric unit. Size-exclusion chromatography, dynamic light scattering and crystal packing indicate that the biological unit is a tetramer in solution. This is further supported by the crystal structure, in which a tetramer is formed using a combination of noncrystallographic and crystallographic twofold axes. A search for structurally homologous proteins revealed that MetY has the same fold as cystathionine γ-lyase and methionine γ-lyase. The active sites of these enzymes, which are also PLP-dependent, share a high degree of structural similarity, suggesting that MetY belongs to the γ-elimination subclass of the Cys/Met metabolism PLP-dependent family of enzymes. The structure of MetY, together with biochemical data, provides insight into the mechanism of sulfur transfer to a small molecule via a protein thiocarboxylate intermediate.

  3. Generation and reactivity of ketyl radicals with lignin related structures. On the importance of the ketyl pathway in the photoyellowing of lignin containing pulps and papers.

    Science.gov (United States)

    Fabbri, Claudia; Bietti, Massimo; Lanzalunga, Osvaldo

    2005-04-01

    [reaction: see text] Ketyl radicals with lignin related structures have been generated by means of radiation chemical and photochemical techniques. In the former studies ketyl radicals are produced by reaction of alpha-carbonyl-beta-aryl ether lignin models with the solvated electron produced by pulse radiolysis of an aqueous solution at pH 6.0. The UV-vis spectra of ketyl radicals are characterized by three main absorption bands. The shape and position of these bands slightly change when the spectra are recorded in alkaline solution (pH 11.0) being now assigned to the ketyl radical anions and a pKa = 9.5 is determined for the 1-(3,4,5-trimethoxyphenyl)-2-phenoxyethanol-1-yl radical. Decay rates of ketyl radicals are found to be dose dependent and, at low doses, lie in the range (1.7-2.7) x 10(3) s(-1). In the presence of oxygen a fast decay of the ketyl radicals is observed (k2 = 1.8-2.7 x 10(9) M(-1) s(-1)) that is accompanied by the formation of stable products, i.e., the starting ketones. In the photochemical studies ketyl radicals have been produced by charge-transfer (CT) photoactivation of the electron donor-acceptor salts of methyl viologen (MV2+) with alpha-hydroxy-alpha-phenoxymethyl-aryl acetates. This process leads to the instantaneous formation of the reduced acceptor (methyl viologen radical cation, MV+*), as is clearly shown in a laser flash photolysis experiment by the two absorption bands centered at 390 and 605 nm, and an acyloxyl radical [ArC(CO2*))(OH)CH2(OC6H5)], which undergoes a very fast decarboxylation with formation of the ketyl radicals. Steady-state photoirradiation of the CT ion pairs indicates that 1-aryl-2-phenoxyethanones are formed as primary photoproducts by oxidation of ketyl radicals by MV2+ (under argon) or by molecular oxygen. Small amounts of acetophenones are formed by further photolysis of 1-aryl-2-phenoxyethanones and not by beta-fragmentation of the ketyl radicals. The high reactivity of ketyl radicals with oxygen coupled

  4. Tat proteins as novel thylakoid membrane anchors organize a biosynthetic pathway in chloroplasts and increase product yield 5-fold

    DEFF Research Database (Denmark)

    Henriques de Jesus, Maria Perestrello Ramos; Nielsen, Agnieszka Janina Zygadlo; Mellor, Silas Busck

    2017-01-01

    to their complex structures. Some of the crucial enzymes catalyzing their biosynthesis are the cytochromes P450 (P450s) situated in the endoplasmic reticulum (ER), powered by electron transfers from NADPH. Dhurrin is a cyanogenic glucoside and its biosynthesis involves a dynamic metabolon formed by two P450s....... Nevertheless, translocation of the pathway from the ER to the chloroplast creates other difficulties, such as the loss of metabolon formation and intermediate diversion into other metabolic pathways. We show here that co-localization of these enzymes in the thylakoid membrane leads to a significant increase...... in product formation, with a concomitant decrease in off-pathway intermediates. This was achieved by exchanging the membrane anchors of the dhurrin pathway enzymes to components of the Twin-arginine translocation pathway, TatB and TatC, which have self-assembly properties. Consequently, we show 5-fold...

  5. Novel NAD+-Farnesal Dehydrogenase from Polygonum minus Leaves. Purification and Characterization of Enzyme in Juvenile Hormone III Biosynthetic Pathway in Plant.

    Directory of Open Access Journals (Sweden)

    Ahmad-Faris Seman-Kamarulzaman

    Full Text Available Juvenile Hormone III is of great concern due to negative effects on major developmental and reproductive maturation in insect pests. Thus, the elucidation of enzymes involved JH III biosynthetic pathway has become increasing important in recent years. One of the enzymes in the JH III biosynthetic pathway that remains to be isolated and characterized is farnesal dehydrogenase, an enzyme responsible to catalyze the oxidation of farnesal into farnesoic acid. A novel NAD+-farnesal dehydrogenase of Polygonum minus was purified (315-fold to apparent homogeneity in five chromatographic steps. The purification procedures included Gigacap S-Toyopearl 650M, Gigacap Q-Toyopearl 650M, and AF-Blue Toyopearl 650ML, followed by TSK Gel G3000SW chromatographies. The enzyme, with isoelectric point of 6.6 is a monomeric enzyme with a molecular mass of 70 kDa. The enzyme was relatively active at 40°C, but was rapidly inactivated above 45°C. The optimal temperature and pH of the enzyme were found to be 35°C and 9.5, respectively. The enzyme activity was inhibited by sulfhydryl agent, chelating agent, and metal ion. The enzyme was highly specific for farnesal and NAD+. Other terpene aldehydes such as trans- cinnamaldehyde, citral and α- methyl cinnamaldehyde were also oxidized but in lower activity. The Km values for farnesal, citral, trans- cinnamaldehyde, α- methyl cinnamaldehyde and NAD+ were 0.13, 0.69, 0.86, 1.28 and 0.31 mM, respectively. The putative P. minus farnesal dehydrogenase that's highly specific towards farnesal but not to aliphatic aldehydes substrates suggested that the enzyme is significantly different from other aldehyde dehydrogenases that have been reported. The MALDI-TOF/TOF-MS/MS spectrometry further identified two peptides that share similarity to those of previously reported aldehyde dehydrogenases. In conclusion, the P. minus farnesal dehydrogenase may represent a novel plant farnesal dehydrogenase that exhibits distinctive substrate

  6. Differential control of the cholesterol biosynthetic pathway in tumor versus liver: evidence for decontrolled tumor cholesterogenesis in a cell-free system

    International Nuclear Information System (INIS)

    Azrolan, N.

    1987-01-01

    Cholesterol biosynthesis was characterized in cell-free post-mitochondrial supernatant (PMS) systems prepared from both normal rat liver and Morris hepatoma 3924A. Per cell, the rate of cholesterol synthesis from either 14 C-citrate of 14 -acetate in the hepatoma system was 9-fold greater than that observed in the liver system. Furthermore, the ratio of sterol-to-fatty acid synthesis rates from 14 C-citrate was more than 3-fold greater in the tumor than in the normal liver system. Incubations using radiolabeled acetate and mevalonate have demonstrated the loss of a normally rate-limiting control site within the early portion of the cholesterol biosynthetic pathway in the tumor system. Upon analysis of the steady-state levels of early lipogenic intermediates, the specific site of decontrol in the tumor was identified as the 3-hydroxy-3-methylglutaryl-CoA → mevalonate site of this pathway. In contrast, this reaction appeared to retain its rate-limiting properties in the cell-free system from normal liver

  7. Lignin biodegradation and industrial implications

    Directory of Open Access Journals (Sweden)

    Adam B Fisher

    2014-12-01

    Full Text Available Lignocellulose, which comprises the cell walls of plants, is the Earth’s most abundant renewable source of convertible biomass. However, in order to access the fermentable sugars of the cellulose and hemicellulose fraction, the extremely recalcitrant lignin heteropolymer must be hydrolyzed and removed—usually by harsh, costly thermochemical pretreatments. Biological processes for depolymerizing and metabolizing lignin present an opportunity to improve the overall economics of the lignocellulosic biorefinery by facilitating pretreatment, improving downstream cellulosic fermentations or even producing a valuable effluent stream of aromatic compounds for creating value-added products. In the following review we discuss background on lignin, the enzymology of lignin degradation, and characterized catabolic pathways for metabolizing the by-products of lignin degradation. To conclude we survey advances in approaches to identify novel lignin degrading phenotypes and applications of these phenotypes in the lignocellulosic bioprocess.

  8. Synthesis of C-Glucosylated Octaketide Anthraquinones in Nicotiana benthamiana by Using a Multispecies-Based Biosynthetic Pathway

    DEFF Research Database (Denmark)

    Andersen-Ranberg, Johan; Kongstad, Kenneth Thermann; Nafisi, Majse

    2017-01-01

    unsuccessful. Herein, a novel combination of enzymes derived from a plant (Aloe arborescens, Aa), a bacterium (Streptomyces sp. R1128, St), and an insect (Dactylopius coccus, Dc) that allows for the biosynthesis of the C-glucosylated anthraquinone, dcII, a precursor for carminic acid, is reported. The pathway...

  9. A novel deconvolution method for modeling UDP-N-acetyl-D-glucosamine biosynthetic pathways based on 13C mass isotopologue profiles under non-steady-state conditions

    Directory of Open Access Journals (Sweden)

    Belshoff Alex C

    2011-05-01

    Full Text Available Abstract Background Stable isotope tracing is a powerful technique for following the fate of individual atoms through metabolic pathways. Measuring isotopic enrichment in metabolites provides quantitative insights into the biosynthetic network and enables flux analysis as a function of external perturbations. NMR and mass spectrometry are the techniques of choice for global profiling of stable isotope labeling patterns in cellular metabolites. However, meaningful biochemical interpretation of the labeling data requires both quantitative analysis and complex modeling. Here, we demonstrate a novel approach that involved acquiring and modeling the timecourses of 13C isotopologue data for UDP-N-acetyl-D-glucosamine (UDP-GlcNAc synthesized from [U-13C]-glucose in human prostate cancer LnCaP-LN3 cells. UDP-GlcNAc is an activated building block for protein glycosylation, which is an important regulatory mechanism in the development of many prominent human diseases including cancer and diabetes. Results We utilized a stable isotope resolved metabolomics (SIRM approach to determine the timecourse of 13C incorporation from [U-13C]-glucose into UDP-GlcNAc in LnCaP-LN3 cells. 13C Positional isotopomers and isotopologues of UDP-GlcNAc were determined by high resolution NMR and Fourier transform-ion cyclotron resonance-mass spectrometry. A novel simulated annealing/genetic algorithm, called 'Genetic Algorithm for Isotopologues in Metabolic Systems' (GAIMS was developed to find the optimal solutions to a set of simultaneous equations that represent the isotopologue compositions, which is a mixture of isotopomer species. The best model was selected based on information theory. The output comprises the timecourse of the individual labeled species, which was deconvoluted into labeled metabolic units, namely glucose, ribose, acetyl and uracil. The performance of the algorithm was demonstrated by validating the computed fractional 13C enrichment in these subunits

  10. Pederin-type pathways of uncultivated bacterial symbionts: analysis of o-methyltransferases and generation of a biosynthetic hybrid.

    Science.gov (United States)

    Zimmermann, Katrin; Engeser, Marianne; Blunt, John W; Munro, Murray H G; Piel, Jörn

    2009-03-04

    The complex polyketide pederin is a potent antitumor agent isolated from Paederus spp. rove beetles. We have previously isolated a set of genes from a bacterial endosymbiont that are good candidates for pederin biosynthesis. To biochemically study this pathway, we expressed three methyltransferases from the putative pederin pathway and used the partially unmethylated analogue mycalamide A from the marine sponge Mycale hentscheli as test substrate. Analysis by high-resolution MS/MS and NMR revealed that PedO regiospecifically methylates the marine compound to generate the nonnatural hybrid compound 18-O-methylmycalamide A with increased cytotoxicity. To our knowledge, this is the first biochemical evidence that invertebrates can obtain defensive complex polyketides from bacterial symbionts.

  11. Genetic Characterization of the Carotenoid Biosynthetic Pathway in Methylobacterium extorquens AM1 and Isolation of a Colorless Mutant

    OpenAIRE

    Van Dien, Stephen J.; Marx, Christopher J.; O'Brien, Brooke N.; Lidstrom, Mary E.

    2003-01-01

    Genomic searches were used to reconstruct the putative carotenoid biosynthesis pathway in the pink-pigmented facultative methylotroph Methylobacterium extorquens AM1. Four genes for putative phytoene desaturases were identified. A colorless mutant was obtained by transposon mutagenesis, and the insertion was shown to be in one of the putative phytoene desaturase genes. Mutations in the other three did not affect color. The tetracycline marker was removed from the original transposon mutant, r...

  12. Lignin Macromolecule

    Indian Academy of Sciences (India)

    plant or a structural component of a mature plant which is detected by certain colour reactions. An enzymologist has termed lignin as the ... a phenyl-propanoid structure. A soil chemist considers lignin to be the residue of .... refer to the hardness of wood, but to the botanical classifications. They are aptly called gymnosperms ...

  13. Genetic Characterization of the Carotenoid Biosynthetic Pathway in Methylobacterium extorquens AM1 and Isolation of a Colorless Mutant

    Science.gov (United States)

    Van Dien, Stephen J.; Marx, Christopher J.; O'Brien, Brooke N.; Lidstrom, Mary E.

    2003-01-01

    Genomic searches were used to reconstruct the putative carotenoid biosynthesis pathway in the pink-pigmented facultative methylotroph Methylobacterium extorquens AM1. Four genes for putative phytoene desaturases were identified. A colorless mutant was obtained by transposon mutagenesis, and the insertion was shown to be in one of the putative phytoene desaturase genes. Mutations in the other three did not affect color. The tetracycline marker was removed from the original transposon mutant, resulting in a pigment-free strain with wild-type growth properties useful as a tool for future experiments. PMID:14660416

  14. Genetic characterization of the carotenoid biosynthetic pathway in Methylobacterium extorquens AM1 and isolation of a colorless mutant.

    Science.gov (United States)

    Van Dien, Stephen J; Marx, Christopher J; O'Brien, Brooke N; Lidstrom, Mary E

    2003-12-01

    Genomic searches were used to reconstruct the putative carotenoid biosynthesis pathway in the pink-pigmented facultative methylotroph Methylobacterium extorquens AM1. Four genes for putative phytoene desaturases were identified. A colorless mutant was obtained by transposon mutagenesis, and the insertion was shown to be in one of the putative phytoene desaturase genes. Mutations in the other three did not affect color. The tetracycline marker was removed from the original transposon mutant, resulting in a pigment-free strain with wild-type growth properties useful as a tool for future experiments.

  15. Structure and Functional Analysis of ClbQ, an Unusual Intermediate-Releasing Thioesterase from the Colibactin Biosynthetic Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Guntaka, Naga Sandhya; Healy, Alan R.; Crawford, Jason M.; Herzon, Seth B.; Bruner, Steven D. (Yale); (Florida); (Yale-MED)

    2017-09-08

    Colibactin is a genotoxic hybrid nonribosomal peptide/polyketide secondary metabolite produced by various pathogenic and probiotic bacteria residing in the human gut. The presence of colibactin metabolites has been correlated to colorectal cancer formation in several studies. The specific function of many gene products in the colibactin gene cluster can be predicted. However, the role of ClbQ, a type II editing thioesterase, has not been established. The importance of ClbQ has been demonstrated by genetic deletions that abolish colibactin cytotoxic activity, and recent studies suggest an atypical role in releasing pathway intermediates from the assembly line. Here we report the 2.0 Å crystal structure and biochemical characterization of ClbQ. Our data reveal that ClbQ exhibits greater catalytic efficiency toward acyl-thioester substrates as compared to precolibactin intermediates and does not discriminate among carrier proteins. Cyclized pyridone-containing colibactins, which are off-pathway derivatives, are not viable substrates for ClbQ, while linear precursors are, supporting a role of ClbQ in facilitating the promiscuous off-loading of premature precolibactin metabolites and novel insights into colibactin biosynthesis.

  16. Structure and Functional Analysis of ClbQ, an Unusual Intermediate-Releasing Thioesterase from the Colibactin Biosynthetic Pathway.

    Science.gov (United States)

    Guntaka, Naga Sandhya; Healy, Alan R; Crawford, Jason M; Herzon, Seth B; Bruner, Steven D

    2017-10-20

    Colibactin is a genotoxic hybrid nonribosomal peptide/polyketide secondary metabolite produced by various pathogenic and probiotic bacteria residing in the human gut. The presence of colibactin metabolites has been correlated to colorectal cancer formation in several studies. The specific function of many gene products in the colibactin gene cluster can be predicted. However, the role of ClbQ, a type II editing thioesterase, has not been established. The importance of ClbQ has been demonstrated by genetic deletions that abolish colibactin cytotoxic activity, and recent studies suggest an atypical role in releasing pathway intermediates from the assembly line. Here we report the 2.0 Å crystal structure and biochemical characterization of ClbQ. Our data reveal that ClbQ exhibits greater catalytic efficiency toward acyl-thioester substrates as compared to precolibactin intermediates and does not discriminate among carrier proteins. Cyclized pyridone-containing colibactins, which are off-pathway derivatives, are not viable substrates for ClbQ, while linear precursors are, supporting a role of ClbQ in facilitating the promiscuous off-loading of premature precolibactin metabolites and novel insights into colibactin biosynthesis.

  17. Gene transcript profiles of the TIA biosynthetic pathway in response to ethylene and copper reveal their interactive role in modulating TIA biosynthesis in Catharanthus roseus.

    Science.gov (United States)

    Pan, Ya-Jie; Liu, Jia; Guo, Xiao-Rui; Zu, Yuan-Gang; Tang, Zhong-Hua

    2015-05-01

    Research on transcriptional regulation of terpenoid indole alkaloid (TIA) biosynthesis of the medicinal plant, Catharanthus roseus, has largely been focused on gene function and not clustering analysis of multiple genes at the transcript level. Here, more than ten key genes encoding key enzyme of alkaloid synthesis in TIA biosynthetic pathways were chosen to investigate the integrative responses to exogenous elicitor ethylene and copper (Cu) at both transcriptional and metabolic levels. The ethylene-induced gene transcripts in leaves and roots, respectively, were subjected to principal component analysis (PCA) and the results showed the overall expression of TIA pathway genes indicated as the Q value followed a standard normal distribution after ethylene treatments. Peak gene expression was at 15-30 μM of ethephon, and the pre-mature leaf had a higher Q value than the immature or mature leaf and root. Treatment with elicitor Cu found that Cu up-regulated overall TIA gene expression more in roots than in leaves. The combined effects of Cu and ethephon on TIA gene expression were stronger than their separate effects. It has been documented that TIA gene expression is tightly regulated by the transcriptional factor (TF) ethylene responsive factor (ERF) and mitogen-activated protein kinase (MAPK) cascade. The loading plot combination with correlation analysis for the genes of C. roseus showed that expression of the MPK gene correlated with strictosidine synthase (STR) and strictosidine b-D-glucosidase(SGD). In addition, ERF expression correlated with expression of secologanin synthase (SLS) and tryptophan decarboxylase (TDC), specifically in roots, whereas MPK and myelocytomatosis oncogene (MYC) correlated with STR and SGD genes. In conclusion, the ERF regulates the upstream pathway genes in response to heavy metal Cu mainly in C. roseus roots, while the MPK mainly participates in regulating the STR gene in response to ethylene in pre-mature leaf. Interestingly, the

  18. In silico analysis and expression profiling of miRNAs targeting genes of steviol glycosides biosynthetic pathway and their relationship with steviol glycosides content in different tissues of Stevia rebaudiana.

    Science.gov (United States)

    Saifi, Monica; Nasrullah, Nazima; Ahmad, Malik Mobeen; Ali, Athar; Khan, Jawaid A; Abdin, M Z

    2015-09-01

    miRNAs are emerging as potential regulators of the gene expression. Their proven promising role in regulating biosynthetic pathways related gene networks may hold the key to understand the genetic regulation of these pathways which may assist in selection and manipulation to get high performing plant genotypes with better secondary metabolites yields and increased biomass. miRNAs associated with genes of steviol glycosides biosynthetic pathway, however, have not been identified so far. In this study miRNAs targeting genes of steviol glycosides biosynthetic pathway were identified for the first time whose precursors were potentially generated from ESTs and nucleotide sequences of Stevia rebaudiana. Thereafter, stem-loop coupled real time PCR based expressions of these miRNAs in different tissues of Stevia rebaudiana were investigated and their relationship pattern was analysed with the expression levels of their target mRNAs as well as steviol glycoside contents. All the miRNAs investigated showed differential expressions in all the three tissues studied, viz. leaves, flowers and stems. Out of the eleven miRNAs validated, the expression levels of nine miRNAs (miR319a, miR319b, miR319c, miR319d, miR319e, miR319f, miR319h, miRstv_7, miRstv_9) were found to be inversely related, while expression levels of the two, i.e. miR319g and miRstv_11 on the contrary, showed direct relation with the expression levels of their target mRNAs and steviol glycoside contents in the leaves, flowers and stems. This study provides a platform for better understanding of the steviol glycosides biosynthetic pathway and these miRNAs can further be employed to manipulate the biosynthesis of these metabolites to enhance their contents and yield in S. rebaudiana. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  19. Indole-3-acetic acid biosynthetic pathway and aromatic amino acid aminotransferase activities in Pantoea dispersa strain GPK.

    Science.gov (United States)

    Kulkarni, G B; Nayak, A S; Sajjan, S S; Oblesha, A; Karegoudar, T B

    2013-05-01

    This investigation deals with the production of IAA by a bacterial isolate Pantoea dispersa strain GPK (PDG) identified by 16S rRNA gene sequence analysis. HPLC and Mass spectral analysis of metabolites from bacterial spent medium revealed that, IAA production by PDG is Trp-dependent and follows indole-3-pyruvic acid (IPyA) pathway. Substrate specificity study of aromatic amino acid aminotransferase (AAT) showed high activities, only when tryptophan (Trp) and α-ketoglutarate (α-kg) were used as substrates. AAT is highly specific for Trp and α-kg as amino group donor and acceptor, respectively. The effect of exogenous IAA on bacterial growth was established. Low concentration of exogenous IAA induced the growth, whereas high concentration decreased the growth of bacterium. PDG treatment significantly increased the root length, shoot length and dry mass of the chickpea and pigeon pea plants. © 2013 The Society for Applied Microbiology.

  20. Identification and functional characterisation of genes encoding the omega-3 polyunsaturated fatty acid biosynthetic pathway from the coccolithophore Emiliania huxleyi.

    Science.gov (United States)

    Sayanova, Olga; Haslam, Richard P; Calerón, Monica Venegas; López, Noemi Ruiz; Worthy, Charlotte; Rooks, Paul; Allen, Michael J; Napier, Johnathan A

    2011-05-01

    The Prymnesiophyceae coccolithophore Emiliania huxleyi is one of the most abundant alga in our oceans and therefore plays a central role in marine foodwebs. E. huxleyi is notable for the synthesis and accumulation of the omega-3 long chain polyunsaturated fatty acid docosahexaenoic acid (DHA; 22:6Δ(4,7,10,13,16,19), n-3) which is accumulated in fish oils and known to have health-beneficial properties to humans, preventing cardiovascular disease and related pathologies. Here we describe the identification and functional characterisation of the five E. huxleyi genes which direct the synthesis of docosahexaenoic acid in this alga. Surprisingly, E. huxleyi does not use the conventional Δ6-pathway, instead using the alternative Δ8-desaturation route which has previously only been observed in a few unrelated microorganisms. Given that E. huxleyi accumulates significant levels of the Δ6-desaturated fatty acid stearidonic acid (18:4Δ(6,9,12,15), n-3), we infer that the biosynthesis of DHA is likely to be metabolically compartmentalised from the synthesis of stearidonic acid. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Improvement of hairy root cultures and plants by changing biosynthetic pathways leading to pharmaceutical metabolites: strategies and applications.

    Science.gov (United States)

    Ludwig-Müller, Jutta; Jahn, Linda; Lippert, Annemarie; Püschel, Joachim; Walter, Antje

    2014-11-01

    A plethora of bioactive plant metabolites has been explored for pharmaceutical, food chemistry and agricultural applications. The chemical synthesis of these structures is often difficult, so plants are favorably used as producers. While whole plants can serve as a source for secondary metabolites and can be also improved by metabolic engineering, more often cell or organ cultures of relevant plant species are of interest. It should be noted that only in few cases the production for commercial application in such cultures has been achieved. Their genetic manipulation is sometimes faster and the production of a specific metabolite is more reliable, because of less environmental influences. In addition, upscaling in bioreactors is nowadays possible for many of these cultures, so some are already used in industry. There are approaches to alter the profile of metabolites not only by using plant genes, but also by using bacterial genes encoding modifying enzymes. Also, strategies to cope with unwanted or even toxic compounds are available. The need for metabolic engineering of plant secondary metabolite pathways is increasing with the rising demand for (novel) compounds with new bioactive properties. Here, we give some examples of recent developments for the metabolic engineering of plants and organ cultures, which can be used in the production of metabolites with interesting properties. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. A complete structural characterization of the desferrioxamine E biosynthetic pathway from the fire blight pathogen Erwinia amylovora.

    Science.gov (United States)

    Salomone-Stagni, Marco; Bartho, Joseph D; Polsinelli, Ivan; Bellini, Dom; Walsh, Martin A; Demitri, Nicola; Benini, Stefano

    2018-02-08

    The Gram-negative bacterium Erwinia amylovora is the etiological agent of fire blight, a devastating disease which affects Rosaceae such as apple, pear and quince. The siderophore desferrioxamine E plays an important role in bacterial pathogenesis by scavenging iron from the host. DfoJ, DfoA and DfoC are the enzymes responsible for desferrioxamine production starting from lysine. We have determined the crystal structures of each enzyme in the desferrioxamine E pathway and demonstrate that the biosynthesis involves the concerted action of DfoJ, followed by DfoA and lastly DfoC. These data provide the first crystal structures of a Group II pyridoxal-dependent lysine decarboxylase, a cadaverine monooxygenase and a desferrioxamine synthetase. DfoJ is a homodimer made up of three domains. Each monomer contributes to the completion of the active site, which is positioned at the dimer interface. DfoA is the first structure of a cadaverine monooxygenase. It forms homotetramers whose subunits are built by two domains: one for FAD and one for NADP + binding, the latter of which is formed by two subdomains. We propose a model for substrate binding and the role of residues 43-47 as gate keepers for FAD binding and the role of Arg97 in cofactors turnover. DfoC is the first structure of a desferrioxamine synthetase and the first of a multi-enzyme siderophore synthetase coupling an acyltransferase domain with a Non-Ribosomal Peptide Synthetase (NRPS)-Independent Siderophore domain (NIS). Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Diversity, biological roles and biosynthetic pathways for sugar-glycerate containing compatible solutes in bacteria and archaea.

    Science.gov (United States)

    Empadinhas, Nuno; da Costa, Milton S

    2011-08-01

    A decade ago the compatible solutes mannosylglycerate (MG) and glucosylglycerate (GG) were considered to be rare in nature. Apart from two species of thermophilic bacteria, Thermus thermophilus and Rhodothermus marinus, and a restricted group of hyperthermophilic archaea, the Thermococcales, MG had only been identified in a few red algae. Glucosylglycerate was considered to be even rarer and had only been detected as an insignificant solute in two halophilic microorganisms, a cyanobacterium, as a component of a polysaccharide and of a glycolipid in two actinobacteria. Unlike the hyper/thermophilic MG-accumulating microorganisms, branching close to the root of the Tree of Life, those harbouring GG shared a mesophilic lifestyle. Exceptionally, the thermophilic bacterium Persephonella marina was reported to accumulate GG. However, and especially owing to the identification of the key-genes for MG and GG synthesis and to the escalating numbers of genomes available, a plethora of new organisms with the resources to synthesize these solutes has been recognized. The accumulation of GG as an 'emergency' compatible solute under combined salt stress and nitrogen-deficient conditions now seems to be a disseminated survival strategy from enterobacteria to marine cyanobacteria. In contrast, the thermophilic and extremely radiation-resistant bacterium Rubrobacter xylanophilus is the only actinobacterium known to accumulate MG, and under all growth conditions tested. This review addresses the environmental factors underlying the accumulation of MG, GG and derivatives in bacteria and archaea and their roles during stress adaptation or as precursors for more elaborated macromolecules. The diversity of pathways for MG and GG synthesis as well as those for some of their derivatives is also discussed. The importance of glycerate-derived organic solutes in the microbial world is only now being recognized. Their stress-dependent accumulation and the molecular aspects of their

  4. Structural and Functional Analysis of Campylobacter jejuni PseG: a Udp-sugarhydrolase from the Pseudaminic Acid Biosynthetic Pathway

    Energy Technology Data Exchange (ETDEWEB)

    E Rangarajan; A Proteau; Q Cui; S Logan; Z Potetinova; D Whitfield; E Purisima; M Cygler; A Matte; et al.

    2011-12-31

    Flagella of the bacteria Helicobacter pylori and Campylobacter jejuni are important virulence determinants, whose proper assembly and function are dependent upon glycosylation at multiple positions by sialic acid-like sugars, such as 5,7-diacetamido-3,5,7,9-tetradeoxy-l-glycero-l-manno-nonulosonic acid (pseudaminic acid (Pse)). The fourth enzymatic step in the pseudaminic acid pathway, the hydrolysis of UDP-2,4-diacetamido-2,4,6-trideoxy-{beta}-l-altropyranose to generate 2,4-diacetamido-2,4,6-trideoxy-l-altropyranose, is performed by the nucleotide sugar hydrolase PseG. To better understand the molecular basis of the PseG catalytic reaction, we have determined the crystal structures of C. jejuni PseG in apo-form and as a complex with its UDP product at 1.8 and 1.85 {angstrom} resolution, respectively. In addition, molecular modeling was utilized to provide insight into the structure of the PseG-substrate complex. This modeling identifies a His{sup 17}-coordinated water molecule as the putative nucleophile and suggests the UDP-sugar substrate adopts a twist-boat conformation upon binding to PseG, enhancing the exposure of the anomeric bond cleaved and favoring inversion at C-1. Furthermore, based on these structures a series of amino acid substitution derivatives were constructed, altering residues within the active site, and each was kinetically characterized to examine its contribution to PseG catalysis. In conjunction with structural comparisons, the almost complete inactivation of the PseG H17F and H17L derivatives suggests that His{sup 17} functions as an active site base, thereby activating the nucleophilic water molecule for attack of the anomeric C-O bond of the UDP-sugar. As the PseG structure reveals similarity to those of glycosyltransferase family-28 members, in particular that of Escherichia coli MurG, these findings may also be of relevance for the mechanistic understanding of this important enzyme family.

  5. Next Generation Sequencing and Transcriptome Analysis Predicts Biosynthetic Pathway of Sennosides from Senna (Cassia angustifolia Vahl., a Non-Model Plant with Potent Laxative Properties.

    Directory of Open Access Journals (Sweden)

    Nagaraja Reddy Rama Reddy

    Full Text Available Senna (Cassia angustifolia Vahl. is a world's natural laxative medicinal plant. Laxative properties are due to sennosides (anthraquinone glycosides natural products. However, little genetic information is available for this species, especially concerning the biosynthetic pathways of sennosides. We present here the transcriptome sequencing of young and mature leaf tissue of Cassia angustifolia using Illumina MiSeq platform that resulted in a total of 6.34 Gb of raw nucleotide sequence. The sequence assembly resulted in 42230 and 37174 transcripts with an average length of 1119 bp and 1467 bp for young and mature leaf, respectively. The transcripts were annotated using NCBI BLAST with 'green plant database (txid 33090', Swiss Prot, Kyoto Encylcopedia of Genes & Genomes (KEGG, Cluster of Orthologous Gene (COG and Gene Ontology (GO. Out of the total transcripts, 40138 (95.0% and 36349 (97.7% from young and mature leaf, respectively, were annotated by BLASTX against green plant database of NCBI. We used InterProscan to see protein similarity at domain level, a total of 34031 (young leaf and 32077 (mature leaf transcripts were annotated against the Pfam domains. All transcripts from young and mature leaf were assigned to 191 KEGG pathways. There were 166 and 159 CDS, respectively, from young and mature leaf involved in metabolism of terpenoids and polyketides. Many CDS encoding enzymes leading to biosynthesis of sennosides were identified. A total of 10,763 CDS differentially expressing in both young and mature leaf libraries of which 2,343 (21.7% CDS were up-regulated in young compared to mature leaf. Several differentially expressed genes found functionally associated with sennoside biosynthesis. CDS encoding for many CYPs and TF families were identified having probable roles in metabolism of primary as well as secondary metabolites. We developed SSR markers for molecular breeding of senna. We have identified a set of putative genes involved in

  6. Next Generation Sequencing and Transcriptome Analysis Predicts Biosynthetic Pathway of Sennosides from Senna (Cassia angustifolia Vahl.), a Non-Model Plant with Potent Laxative Properties.

    Science.gov (United States)

    Rama Reddy, Nagaraja Reddy; Mehta, Rucha Harishbhai; Soni, Palak Harendrabhai; Makasana, Jayanti; Gajbhiye, Narendra Athamaram; Ponnuchamy, Manivel; Kumar, Jitendra

    2015-01-01

    Senna (Cassia angustifolia Vahl.) is a world's natural laxative medicinal plant. Laxative properties are due to sennosides (anthraquinone glycosides) natural products. However, little genetic information is available for this species, especially concerning the biosynthetic pathways of sennosides. We present here the transcriptome sequencing of young and mature leaf tissue of Cassia angustifolia using Illumina MiSeq platform that resulted in a total of 6.34 Gb of raw nucleotide sequence. The sequence assembly resulted in 42230 and 37174 transcripts with an average length of 1119 bp and 1467 bp for young and mature leaf, respectively. The transcripts were annotated using NCBI BLAST with 'green plant database (txid 33090)', Swiss Prot, Kyoto Encylcopedia of Genes & Genomes (KEGG), Cluster of Orthologous Gene (COG) and Gene Ontology (GO). Out of the total transcripts, 40138 (95.0%) and 36349 (97.7%) from young and mature leaf, respectively, were annotated by BLASTX against green plant database of NCBI. We used InterProscan to see protein similarity at domain level, a total of 34031 (young leaf) and 32077 (mature leaf) transcripts were annotated against the Pfam domains. All transcripts from young and mature leaf were assigned to 191 KEGG pathways. There were 166 and 159 CDS, respectively, from young and mature leaf involved in metabolism of terpenoids and polyketides. Many CDS encoding enzymes leading to biosynthesis of sennosides were identified. A total of 10,763 CDS differentially expressing in both young and mature leaf libraries of which 2,343 (21.7%) CDS were up-regulated in young compared to mature leaf. Several differentially expressed genes found functionally associated with sennoside biosynthesis. CDS encoding for many CYPs and TF families were identified having probable roles in metabolism of primary as well as secondary metabolites. We developed SSR markers for molecular breeding of senna. We have identified a set of putative genes involved in various

  7. Formal modeling and analysis of the hexosamine biosynthetic pathway: role of O-linked N-acetylglucosamine transferase in oncogenesis and cancer progression

    Directory of Open Access Journals (Sweden)

    Muhammad Tariq Saeed

    2016-09-01

    Full Text Available The alteration of glucose metabolism, through increased uptake of glucose and glutamine addiction, is essential to cancer cell growth and invasion. Increased flux of glucose through the Hexosamine Biosynthetic Pathway (HBP drives increased cellular O-GlcNAcylation (hyper-O-GlcNAcylation and contributes to cancer progression by regulating key oncogenes. However, the association between hyper-O-GlcNAcylation and activation of these oncogenes remains poorly characterized. Here, we implement a qualitative modeling framework to analyze the role of the Biological Regulatory Network in HBP activation and its potential effects on key oncogenes. Experimental observations are encoded in a temporal language format and model checking is applied to infer the model parameters and qualitative model construction. Using this model, we discover step-wise genetic alterations that promote cancer development and invasion due to an increase in glycolytic flux, and reveal critical trajectories involved in cancer progression. We compute delay constraints to reveal important associations between the production and degradation rates of proteins. O-linked N-acetylglucosamine transferase (OGT, an enzyme used for addition of O-GlcNAc during O-GlcNAcylation, is identified as a key regulator to promote oncogenesis in a feedback mechanism through the stabilization of c-Myc. Silencing of the OGT and c-Myc loop decreases glycolytic flux and leads to programmed cell death. Results of network analyses also identify a significant cycle that highlights the role of p53-Mdm2 circuit oscillations in cancer recovery and homeostasis. Together, our findings suggest that the OGT and c-Myc feedback loop is critical in tumor progression, and targeting these mediators may provide a mechanism-based therapeutic approach to regulate hyper-O-GlcNAcylation in human cancer.

  8. Genetic and metabolomic dissection of the ergothioneine and selenoneine biosynthetic pathway in the fission yeast, S. pombe, and construction of an overproduction system.

    Directory of Open Access Journals (Sweden)

    Tomáš Pluskal

    Full Text Available Ergothioneine is a small, sulfur-containing metabolite (229 Da synthesized by various species of bacteria and fungi, which can accumulate to millimolar levels in tissues or cells (e.g. erythrocytes of higher eukaryotes. It is commonly marketed as a dietary supplement due to its proposed protective and antioxidative functions. In this study we report the genes forming the two-step ergothioneine biosynthetic pathway in the fission yeast, Schizosaccharomyces pombe. We identified the first gene, egt1+ (SPBC1604.01, by sequence homology to previously published genes from Neurospora crassa and Mycobacterium smegmatis. We showed, using metabolomic analysis, that the Δegt1 deletion mutant completely lacked ergothioneine and its precursors (trimethyl histidine/hercynine and hercynylcysteine sulfoxide. Since the second step of ergothioneine biosynthesis has not been characterized in eukaryotes, we examined four putative homologs (Nfs1/SPBC21D10.11c, SPAC11D3.10, SPCC777.03c, and SPBC660.12c of the corresponding mycobacterial enzyme EgtE. Among deletion mutants of these genes, only one (ΔSPBC660.12c, designated Δegt2 showed a substantial decrease in ergothioneine, accompanied by accumulation of its immediate precursor, hercynylcysteine sulfoxide. Ergothioneine-deficient strains exhibited no phenotypic defects during vegetative growth or quiescence. To effectively study the role of ergothioneine, we constructed an egt1+ overexpression system by replacing its native promoter with the nmt1+ promoter, which is inducible in the absence of thiamine. We employed three versions of the nmt1 promoter with increasing strength of expression and confirmed corresponding accumulations of ergothioneine. We quantified the intracellular concentration of ergothioneine in S. pombe (0.3, 157.4, 41.6, and up to 1606.3 µM in vegetative, nitrogen-starved, glucose-starved, and egt1+-overexpressing cells, respectively and described its gradual accumulation under long

  9. Biosynthetic routes of hydroxylated carotenoids (xanthophylls) in Marchantia polymorpha, and production of novel and rare xanthophylls through pathway engineering in Escherichia coli.

    Science.gov (United States)

    Takemura, Miho; Maoka, Takashi; Misawa, Norihiko

    2015-03-01

    MpBHY codes for a carotene β-ring 3(,3')-hydroxylase responsible for both zeaxanthin and lutein biosynthesis in liverwort. MpCYP97C functions as an ε-ring hydroxylase (zeinoxanthin 3'-hydroxylase) to produce lutein in liverwort. Xanthophylls are oxygenated or hydroxylated carotenes that are most abundant in the light-harvesting complexes of plants. The plant-type xanthophylls consist of α-xanthophyll (lutein) and β-xanthophylls (zeaxanthin, antheraxanthin, violaxanthin and neoxanthin). The α-xanthophyll and β-xanthophylls are derived from α-carotene and β-carotene by carotene hydroxylase activities, respectively. β-Ring 3,3'-hydroxylase that mediates the route of zeaxanthin from β-carotene via β-cryptoxanthin is present in higher plants and is encoded by the BHY (BCH) gene. On the other hand, CYP97A (or BHY) and CYP97C genes are responsible for β-ring 3-hydroxylation and ε-ring 3'-hydroxylation, respectively, in routes from α-carotene to lutein. To elucidate the evolution of the biosynthetic routes of such hydroxylated carotenoids from carotenes in land plants, we identified and functionally analyzed carotenoid hydroxylase genes of liverwort Marchantia polymorpha L. Three genes homologous to higher plants, BHY, CYP97A, and CYP97C, were isolated and named MpBHY, MpCYP97A, and MpCYP97C, respectively. MpBHY was found to code for β-ring hydroxylase, which is responsible for both routes starting from β-carotene and α-carotene. MpCYP97C functioned as an ε-ring hydroxylase not for α-carotene but for zeinoxanthin, while MpCYP97A showed no hydroxylation activity for β-carotene or α-carotene. These findings suggest the original functions of the hydroxylation enzymes of carotenes in land plants, which are thought to diversify in higher plants. In addition, we generated recombinant Escherichia coli cells, which produced rare and novel carotenoids such as α-echinenone and 4-ketozeinoxanthin, through pathway engineering using bacterial carotenogenic genes

  10. Lignin engineering in field-grown poplar trees affects the endosphere bacterial microbiome.

    Science.gov (United States)

    Beckers, Bram; Op De Beeck, Michiel; Weyens, Nele; Van Acker, Rebecca; Van Montagu, Marc; Boerjan, Wout; Vangronsveld, Jaco

    2016-02-23

    Cinnamoyl-CoA reductase (CCR), an enzyme central to the lignin biosynthetic pathway, represents a promising biotechnological target to reduce lignin levels and to improve the commercial viability of lignocellulosic biomass. However, silencing of the CCR gene results in considerable flux changes of the general and monolignol-specific lignin pathways, ultimately leading to the accumulation of various extractable phenolic compounds in the xylem. Here, we evaluated host genotype-dependent effects of field-grown, CCR-down-regulated poplar trees (Populus tremula × Populus alba) on the bacterial rhizosphere microbiome and the endosphere microbiome, namely the microbiota present in roots, stems, and leaves. Plant-associated bacteria were isolated from all plant compartments by selective isolation and enrichment techniques with specific phenolic carbon sources (such as ferulic acid) that are up-regulated in CCR-deficient poplar trees. The bacterial microbiomes present in the endosphere were highly responsive to the CCR-deficient poplar genotype with remarkably different metabolic capacities and associated community structures compared with the WT trees. In contrast, the rhizosphere microbiome of CCR-deficient and WT poplar trees featured highly overlapping bacterial community structures and metabolic capacities. We demonstrate the host genotype modulation of the plant microbiome by minute genetic variations in the plant genome. Hence, these interactions need to be taken into consideration to understand the full consequences of plant metabolic pathway engineering and its relation with the environment and the intended genetic improvement.

  11. Characterization of the gene encoding serine acetyltransferase, a regulated enzyme of cysteine biosynthesis from the protist parasites Entamoeba histolytica and Entamoeba dispar. Regulation and possible function of the cysteine biosynthetic pathway in Entamoeba.

    Science.gov (United States)

    Nozaki, T; Asai, T; Sanchez, L B; Kobayashi, S; Nakazawa, M; Takeuchi, T

    1999-11-05

    The enteric protist parasites Entamoeba histolytica and Entamoeba dispar possess a cysteine biosynthetic pathway, unlike their mammalian host, and are capable of de novo production of L-cysteine. We cloned and characterized cDNAs that encode the regulated enzyme serine acetyltransferase (SAT) in this pathway from these amoebae by genetic complementation of a cysteine-auxotrophic Escherichia coli strain with the amoebic cDNA libraries. The deduced amino acid sequences of the amoebic SATs exhibited, within the most conserved region, 36-52% identities with the bacterial and plant SATs. The amoebic SATs contain a unique insertion of eight amino acids, also found in the corresponding region of a plasmid-encoded SAT from Synechococcus sp., which showed the highest overall identities to the amoebic SATs. Phylogenetic reconstruction also revealed a close kinship of the amoebic SATs with cyanobacterial SATs. Biochemical characterization of the recombinant E. histolytica SAT revealed several enzymatic features that distinguished the amoebic enzyme from the bacterial and plant enzymes: 1) inhibition by L-cysteine in a competitive manner with L-serine; 2) inhibition by L-cystine; and 3) no association with cysteine synthase. Genetically engineered amoeba strains that overproduced cysteine synthase and SAT were created. The cysteine synthase-overproducing amoebae had a higher level of cysteine synthase activity and total thiol content and revealed increased resistance to hydrogen peroxide. These results indicate that the cysteine biosynthetic pathway plays an important role in antioxidative defense of these enteric parasites.

  12. High-pressure vapor-phase hydrodeoxygenation of lignin-derived oxygenates to hydrocarbons by a PtMo bimetallic catalyst: Product selectivity, reaction pathway, and structural characterization

    Energy Technology Data Exchange (ETDEWEB)

    Yohe, Sara L.; Choudhari, Harshavardhan J.; Mehta, Dhairya D.; Dietrich, Paul J.; Detwiler, Michael D.; Akatay, Cem M.; Stach, Eric A.; Miller, Jeffrey T.; Delgass, W. Nicholas; Agrawal, Rakesh; Ribeiro, Fabio H.

    2016-12-01

    High-pressure, vapor-phase, hydrodeoxygenation (HDO) reactions of dihydroeugenol (2-methoxy-4-propylphenol), as well as other phenolic, lignin-derived compounds, were investigated over a bimetallic platinum and molybdenum catalyst supported on multi-walled carbon nanotubes (5%Pt2.5%Mo/MWCNT). Hydrocarbons were obtained in 100% yield from dihydroeugenol, including 98% yield of the hydrocarbon propylcyclohexane. The final hydrocarbon distribution was shown to be a strong function of hydrogen partial pressure. Kinetic analysis showed three main dihydroeugenol reaction pathways: HDO, hydrogenation, and alkylation. The major pathway occurred via Pt catalyzed hydrogenation of the aromatic ring and methoxy group cleavage to form 4-propylcyclohexanol, then Mo catalyzed removal of the hydroxyl group by dehydration to form propylcyclohexene, followed by hydrogenation of propylcyclohexene on either the Pt or Mo to form the propylcyclohexane. Transalkylation by the methoxy group occurred as a minor side reaction. Catalyst characterization techniques including chemisorption, scanning transmission electron microscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy were employed to characterize the catalyst structure. Catalyst components identified were Pt particles, bimetallic PtMo particles, a Mo carbide-like phase, and Mo oxide phases.

  13. Lignin nanoparticle synthesis

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. Characterization and analysis of CCR and CAD gene families at the whole-genome level for lignin synthesis of stone cells in pear (Pyrus bretschneideri) fruit.

    Science.gov (United States)

    Cheng, Xi; Li, Manli; Li, Dahui; Zhang, Jinyun; Jin, Qing; Sheng, Lingling; Cai, Yongping; Lin, Yi

    2017-11-15

    The content of stone cells has significant effects on the flavour and quality of pear fruit. Previous research suggested that lignin deposition is closely related to stone cell formation. In the lignin biosynthetic pathway, cinnamoyl-CoA reductase (CCR) and cinnamyl alcohol dehydrogenase (CAD), dehydrogenase/reductase family members, catalyse the last two steps in monolignol synthesis. However, there is little knowledge of the characteristics of the CCR and CAD families in pear and their involvement in lignin synthesis of stone cells. In this study, 31 CCR s and 26 CAD s were identified in the pear genome. Phylogenetic trees for CCR s and CAD s were constructed; key amino acid residues were analysed, and three-dimensional structures were predicted. Using quantitative real-time polymerase chain reaction (qRT-PCR), PbCAD2 , PbCCR1 , -2 and - 3 were identified as participating in lignin synthesis of stone cells in pear fruit. Subcellular localization analysis showed that the expressed proteins (PbCAD2, PbCCR1, -2 and -3) are found in the cytoplasm or at the cell membrane. These results reveal the evolutionary features of the CCR and CAD families in pear as well as the genes responsible for regulation of lignin synthesis and stone cell development in pear fruit. © 2017. Published by The Company of Biologists Ltd.

  15. Characterization and analysis of CCR and CAD gene families at the whole-genome level for lignin synthesis of stone cells in pear (Pyrus bretschneideri fruit

    Directory of Open Access Journals (Sweden)

    Xi Cheng

    2017-11-01

    Full Text Available The content of stone cells has significant effects on the flavour and quality of pear fruit. Previous research suggested that lignin deposition is closely related to stone cell formation. In the lignin biosynthetic pathway, cinnamoyl-CoA reductase (CCR and cinnamyl alcohol dehydrogenase (CAD, dehydrogenase/reductase family members, catalyse the last two steps in monolignol synthesis. However, there is little knowledge of the characteristics of the CCR and CAD families in pear and their involvement in lignin synthesis of stone cells. In this study, 31 CCRs and 26 CADs were identified in the pear genome. Phylogenetic trees for CCRs and CADs were constructed; key amino acid residues were analysed, and three-dimensional structures were predicted. Using quantitative real-time polymerase chain reaction (qRT-PCR, PbCAD2, PbCCR1, -2 and -3 were identified as participating in lignin synthesis of stone cells in pear fruit. Subcellular localization analysis showed that the expressed proteins (PbCAD2, PbCCR1, -2 and -3 are found in the cytoplasm or at the cell membrane. These results reveal the evolutionary features of the CCR and CAD families in pear as well as the genes responsible for regulation of lignin synthesis and stone cell development in pear fruit.

  16. Repression of MYBL2 by Both microRNA858a and HY5 Leads to the Activation of Anthocyanin Biosynthetic Pathway in Arabidopsis.

    Science.gov (United States)

    Wang, Yulong; Wang, Yiqing; Song, Zhaoqing; Zhang, Huiyong

    2016-10-10

    Extensive studies in various plants show that the anthocyanin biosynthetic process is affected by environmental factors and regulated by many transcription factors through sophisticated regulatory networks. However, it remains largely unclear about the roles of microRNA in this process. Here, we demonstrate that miR858a is a positive regulator of anthocyanin biosynthesis in Arabidopsis seedlings. Overexpression of miR858a enhances the accumulation of anthocyanins, whereas the reduced miR858a activity results in low levels of anthocyanins in STTM858 transgenic plants. We found that miR858a inhibits the expression of MYBL2, a key negative regulator of anthocyanin biosynthesis, by translational repression. In addition, ELONGATED HYPOCOTYL 5 (HY5) was shown to directly bind the MYBL2 promoter and represses its expression via specific histone modifications. Interestingly, we found that miR858a exhibits light-responsive expression in an HY5-dependent manner. Together, these results delineate the HY5-MIR858a-MYBL2 loop as a cellular mechanism for modulating anthocyanin biosynthesis, suggesting that integration of transcriptional and posttranscriptional regulation is critical for governing proper anthocyanin accumulation in response to light and other environmental factors. Copyright © 2016 The Author. Published by Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

    Anterola, Aldwin M.; Lewis, Norman G.

    2002-01-01

    activities. Such enzymes thus fulfill subsidiary processing roles, with all (except CCOMT) apparently being bifunctional for both H and G substrates. Their severe downregulation does, however, predictably result in impaired monolignol biosynthesis, reduced lignin deposition/vascular integrity, (upstream) metabolite build-up and/or shunt pathway metabolism. There was no evidence for an alternative acid/ester O-methyltransferase (AEOMT) being involved in lignin biosynthesis.The G/S lignin pathway networks are operative in specific cell types in angiosperms and employ two additional biosynthetic steps to afford the corresponding S components, i.e. through introduction of an hydroxyl group at C-5 and its subsequent O-methylation. [These enzymes were originally classified as ferulate-5-hydroxylase (F5H) and caffeate O-methyltransferase (COMT), respectively.] As before, neither step has apparently any role in carbon allocation to the pathway; hence their individual downregulation/manipulation, respectively, gives either a G enriched lignin or formation of the well-known S-deficient bm3 "lignin" mutant, with cell walls of impaired vascular integrity. In the latter case, COMT downregulation/mutation apparently results in utilization of the isoelectronic 5-hydroxyconiferyl alcohol species albeit in an unsuccessful attempt to form G-S lignin proper. However, there is apparently no effect on overall G content, thereby indicating that deposition of both G and S moieties in the G/S lignin forming cells are kept spatially, and presumably temporally, fully separate. Downregulation/mutation of further downstream steps in the G/S network [i.e. utilizing 4CL, CCR and CAD isoforms] gives predictable effects in terms of their subsidiary processing roles: while severe downregulation of 4CL gave phenotypes with impaired vascular integrity due to reduced monolignol supply, there was no evidence in support of increased growth and/or enhanced cellulose biosynthesis. CCR and CAD downregulation

  18. Computational study on a puzzle in the biosynthetic pathway of anthocyanin: Why is an enzymatic oxidation/ reduction process required for a simple tautomerization?

    Science.gov (United States)

    Sato, Hajime; Wang, Chao; Yamazaki, Mami; Saito, Kazuki; Uchiyama, Masanobu

    2018-01-01

    In the late stage of anthocyanin biosynthesis, dihydroflavonol reductase (DFR) and anthocyanidin synthase (ANS) mediate a formal tautomerization. However, such oxidation/reduction process requires high energy and appears to be unnecessary, as the oxidation state does not change during the transformation. Thus, a non-enzymatic pathway of tautomerization has also been proposed. To resolve the long-standing issue of whether this non-enzymatic pathway is the main contributor for the biosynthesis, we carried out density functional theory (DFT) calculations to examine this non-enzymatic pathway from dihydroflavonol to anthocyanidin. We show here that the activation barriers for the proposed non-enzymatic tautomerization are too high to enable the reaction to proceed under normal aqueous conditions in plants. The calculations also explain the experimentally observed requirement for acidic conditions during the final step of conversion of 2-flaven-3,4-diol to anthocyanidin; a thermodynamically and kinetically favorable concerted pathway can operate under these conditions.

  19. Biosynthetic pathways to delta-aminolevulinic acid induced by blue light in the pigment mutant C-2A' of Scenedesmus obliquus

    International Nuclear Information System (INIS)

    Klein, O.; Senger, H.

    1978-01-01

    The X-ray induced mutant C-2A' of Scenedesmus obliquus grows heterotrophically but forms only traces of chlorophyll in the dark. Upon illumination, delta-aminolevulinic acid (ALA) is synthesized and chlorophyll is formed. These processes are blue light dependent and ceased immediately when the cells were transferred back into darkness. Addition of levulinic acid (LA) inhibited the light-dependent formation of chlorophyll and caused accumulation of ALA by competitive inhibition of the ALA dehydratase (EC. 4.2.1.24). By feeding specifically labelled 14 C precursors to the pigment mutant, inhibiting the ALA dehydratase with LA, accumulating, extracting and analyzing the ALA, two pathways leading towards ALA could be established: glycine and succinyl CoA can be condensed to ALA and the 5 carbon skeleton of glutamate can completely be incorporated into ALA via a second pathway. The glycine-succinyl CoA pathway dominated over the glutamate pathway, but both led to chlorophyll formation. (author)

  20. Characterization of a SAM-dependent fluorinase from a latent biosynthetic pathway for fluoroacetate and 4-fluorothreonine formation in Nocardia brasiliensis.

    Science.gov (United States)

    Wang, Yaya; Deng, Zixin; Qu, Xudong

    2014-01-01

    Fluorination has been widely used in chemical synthesis, but is rare in nature. The only known biological fluorination scope is represented by the fl pathway from Streptomyces cattleya that produces fluoroacetate (FAc) and 4-fluorothreonine (4-FT). Here we report the identification of a novel pathway for FAc and 4-FT biosynthesis from the actinomycetoma-causing pathogen Nocardia brasiliensis ATCC 700358. The new pathway shares overall conservation with the fl pathway in S. cattleya. Biochemical characterization of the conserved domains revealed a novel fluorinase NobA that can biosynthesize 5'-fluoro-5'-deoxyadenosine (5'-FDA) from inorganic fluoride and S-adenosyl-l-methionine (SAM). The NobA shows similar halide specificity and characteristics to the fluorination enzyme FlA of the fl pathway. Kinetic parameters for fluoride ( K m 4153 μM, k cat 0.073 min (-1)) and SAM ( K m 416 μM, k cat 0.139 min (-1)) have been determined, revealing that NobA is slightly (2.3 fold) slower than FlA. Upon sequence comparison, we finally identified a distinct loop region in the fluorinases that probably accounts for the disparity of fluorination activity.

  1. Modulating lignin in plants

    Science.gov (United States)

    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.

  2. Radical SAM, A Novel Protein Superfamily Linking Unresolved Steps in Familiar Biosynthetic Pathways with Radical Mechanisms: Functional Characterization Using New Analysis and Information Visualization Methods

    Energy Technology Data Exchange (ETDEWEB)

    Sofia, Heidi J.; Chen, Guang; Hetzler, Elizabeth G.; Reyes Spindola, Jorge F.; Miller, Nancy E.

    2001-03-01

    A large protein superfamily with over 500 members has been discovered and analyzed using powerful new bioinformatics and information visualization methods. Evidence exists that these proteins generate a 5?-deoxyadenosyl radical by reductive cleavage of S-adenosylmethionine (SAM) through an unusual Fe-S center. Radical SAM superfamily proteins function in DNA precursor, vitamin, cofactor, antibiotic, and herbicide biosynthesis in a collection of basic and familiar pathways. One of the members is interferon-inducible and is considered a candidate drug target for osteoporosis. The identification of this superfamily suggests that radical-based catalysis is important in a number of previously well-studied but unresolved biochemical pathways.

  3. Promzea: a pipeline for discovery of co-regulatory motifs in maize and other plant species and its application to the anthocyanin and phlobaphene biosynthetic pathways and the Maize Development Atlas.

    Science.gov (United States)

    Liseron-Monfils, Christophe; Lewis, Tim; Ashlock, Daniel; McNicholas, Paul D; Fauteux, François; Strömvik, Martina; Raizada, Manish N

    2013-03-15

    The discovery of genetic networks and cis-acting DNA motifs underlying their regulation is a major objective of transcriptome studies. The recent release of the maize genome (Zea mays L.) has facilitated in silico searches for regulatory motifs. Several algorithms exist to predict cis-acting elements, but none have been adapted for maize. A benchmark data set was used to evaluate the accuracy of three motif discovery programs: BioProspector, Weeder and MEME. Analysis showed that each motif discovery tool had limited accuracy and appeared to retrieve a distinct set of motifs. Therefore, using the benchmark, statistical filters were optimized to reduce the false discovery ratio, and then remaining motifs from all programs were combined to improve motif prediction. These principles were integrated into a user-friendly pipeline for motif discovery in maize called Promzea, available at http://www.promzea.org and on the Discovery Environment of the iPlant Collaborative website. Promzea was subsequently expanded to include rice and Arabidopsis. Within Promzea, a user enters cDNA sequences or gene IDs; corresponding upstream sequences are retrieved from the maize genome. Predicted motifs are filtered, combined and ranked. Promzea searches the chosen plant genome for genes containing each candidate motif, providing the user with the gene list and corresponding gene annotations. Promzea was validated in silico using a benchmark data set: the Promzea pipeline showed a 22% increase in nucleotide sensitivity compared to the best standalone program tool, Weeder, with equivalent nucleotide specificity. Promzea was also validated by its ability to retrieve the experimentally defined binding sites of transcription factors that regulate the maize anthocyanin and phlobaphene biosynthetic pathways. Promzea predicted additional promoter motifs, and genome-wide motif searches by Promzea identified 127 non-anthocyanin/phlobaphene genes that each contained all five predicted promoter

  4. Metabolic Profiling of Primary and Secondary Biosynthetic Pathways in Angiosperms: Comparative Metabonomics and Applications of Hyphenated LC-NMR and LC-MS

    OpenAIRE

    Kaiser, Kayla Anne

    2012-01-01

    The goal of this dissertation was to advance plant metabolomics through optimization of biological experimental design, sampling and sample preparation, data acquisition and pre-processing, and multivariable data analysis. The analytical platform most employed for comparative metabonomics was nuclear magnetic resonance (NMR). Liquid-chromatography (LC) coupled to NMR and mass spectrometry (MS) extended metabolic profile coverage from primary into secondary metabolic pathways. Comparative p...

  5. Lignin Valorization: Emerging Approaches

    Energy Technology Data Exchange (ETDEWEB)

    Beckham, Gregg T [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-04-03

    Lignin, an aromatic biopolymer found in plant cell walls, is a key component of lignocellulosic biomass and generally utilized for heat and power. However, lignin's chemical composition makes it an attractive source for biological and catalytic conversion to fuels and chemicals. Bringing together experts from biology, catalysis, engineering, analytical chemistry, and techno-economic/life-cycle analysis, Lignin Valorization presents a comprehensive, interdisciplinary picture of how lignocellulosic biorefineries could potentially employ lignin valorization technologies. Chapters will specifically focus on the production of fuels and chemicals from lignin and topics covered include (i) methods for isolating lignin in the context of the lignocellulosic biorefinery, (ii) thermal, chemo-catalytic, and biological methods for lignin depolymerization, (iii) chemo-catalytic and biological methods for upgrading lignin, (iv) characterization of lignin, and (v) techno-economic and life-cycle analysis of integrated processes to utilize lignin in an integrated biorefinery. The book provides the latest breakthroughs and challenges in upgrading lignin to fuels and chemicals for graduate students and researchers in academia, governmental laboratories, and industry interested in biomass conversion.

  6. Endogenous gibberellins in Arabidopsis thaliana and possible steps blocked in the biosynthetic pathways of the semidwarf ga4 and ga5 mutants

    International Nuclear Information System (INIS)

    Talon, M.; Zeevaart, J.A.D.; Koornneef, M.

    1990-01-01

    Twenty gibberellins (GAs) have been identified in extracts from shoots of the Landsberg erecta line of Arabidopsis thaliana by full-scan gas chromatography-mass spectrometry and Kovats retention indices. Eight of them are members of the early-13-hydroxylation pathway (GA 53 , GA 44 , GA 19 , GA 17 , GA 20 , GA 1 , GA 29 , and GA 8 ), six are members of the early-3-hydroxylation pathway (GA 37 , GA 27 , GA 36 , GA 13 , GA 4 , and GA 34 ), and the remaining six are members of the non-3,13-hydroxylation pathway (GA 12 , GA 15 , GA 24 , GA 25 , GA 9 , and GFA 51 ). Seven of these GAs were quantified in the Landsberg erecta line of Arabidopsis and in the semidwarf ga4 and ga5 mutants by gas chromatography-selected ion monitoring (SIM) using internal standards. The relative levels of the remaining 13 GAs were compared by the use of ion intensities only. The growth-response data, as well as the accumulation of GA 9 in the ga4 mutant, indicate that GA 9 is not active in Arabidopsis, but it must be 3β-hydroxytlated to GA 4 to become bioactive. It is concluded that the reduced levels of the 3β-hydroxy-GAs, GA 1 and GA 4 , are the cause of the semidwarf growth habit of both mutants

  7. Quantitative evaluation of the biosynthetic pathways leading to δ-aminolevulinic acid from the Shemin precursor glycine via the C5 pathway in Arthrobacter hyalinus by analysis of 13C-labeled coproporphyrinogen III biosynthesized from [2-13C]glycine, [1-13C]acetate, and [2-13C]acetate using 13C NMR spectroscopy

    International Nuclear Information System (INIS)

    Katsumi Iida

    2013-01-01

    The biosynthetic pathways leading to δ-aminolevulinic acid (ALA) from the Shemin precursor glycine via the C5 pathway in Arthrobacter hyalinus were quantitatively evaluated by means of feeding experiments with [2- 13 C]glycine, sodium [1- 13 C]acetate, and sodium [2- 13 C]acetate, followed by analysis of the labeling patterns of coproporphyrinogen III (Copro'gen III) (biosynthesized from ALA) using 13 C NMR spectroscopy. Two biosynthetic pathways leading to ALA from glycine via the C5 pathway were identified: i.e., transformation of glycine to l-serine catalyzed by glycine hydroxymethyltransferase, and glycine synthase-catalyzed catabolism of glycine to N 5 , N 10 -methylene-tetrahydrofolic acid (THF), which reacts with another molecule of glycine to afford l-serine. l-Serine is transformed to acetyl-CoA via pyruvic acid. Acetyl-CoA enters the tricarboxylic acid cycle, affording 2-oxoglutaric acid, which in turn is transformed to l-glutamic acid. The l-glutamic acid enters the C5 pathway, affording ALA in A. hyalinus. A 13 C NMR spectroscopic comparison of the labeling patterns of Copro'gen III obtained after feeding of [2- 13 C]glycine, sodium [1- 13 C]acetate, and sodium [2- 13 C]acetate showed that [2- 13 C]glycine transformation and [2- 13 C]glycine catabolism in A. hyalinus proceed in the ratio of 52 and 48 %. The reaction of [2- 13 C]glycine and N 5 , N 10 -methylene-THF, that of glycine and N 5 , N 10 -[methylene- 13 C]methylene-THF generated from the [2- 13 C]glycine catabolism, and that of [2- 13 C]glycine and N 5 , N 10 -[methylene- 13 C]methylene-THF transformed the fed [2- 13 C]glycine to [1- 13 C]acetyl-CoA, [2- 13 C]acetyl-CoA, and [1,2- 13 C 2 ]acetyl-CoA in the ratios of 42, 37, and 21 %, respectively. These labeled acetyl-CoAs were then incorporated into ALA. Our results provide a quantitative picture of the pathways of biosynthetic transformation to ALA from glycine in A. hyalinus. (author)

  8. Biodegradation of alkaline lignin by Bacillus ligniniphilus L1

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Daochen; Zhang, Peipei; Xie, Changxiao; Zhang, Weimin; Sun, Jianzhong; Qian, Wei-Jun; Yang, Bin

    2017-02-21

    Background: Lignin is the most abundant aromatic biopolymer in the biosphere and it comprises up to 30% of plant biomass. Although lignin is the most recalcitrant component of the plant cell wall, still there are microorganisms able to decompose it or degrade it. Fungi are recognized as the most widely used microbes for lignin degradation. However, bacteria have also been known to be able to utilize lignin as a carbon or energy source. Bacillus ligniniphilus L1 was selected in this study due to its capability to utilize alkaline lignin as a single carbon or energy source and its excellent ability to survive in extreme environments. Results: To investigate the aromatic metabolites of strain L1 decomposing alkaline lignin, GC-MS analyze was performed and fifteen single phenol ring aromatic compounds were identified. The dominant absorption peak included phenylacetic acid, 4-hydroxy-benzoicacid, and vanillic acid with the highest proportion of metabolites resulting in 42%. Comparison proteomic analysis were carried out for further study showed that approximately 1447 kinds of proteins were produced, 141 of which were at least 2-fold up-regulated with alkaline lignin as the single carbon source. The up-regulated proteins contents different categories in the biological functions of protein including lignin degradation, ABC transport system, environmental response factors, protein synthesis and assembly, etc. Conclusions: GC-MS analysis showed that alkaline lignin degradation of strain L1 produced 15 kinds of aromatic compounds. Comparison proteomic data and metabolic analysis showed that to ensure the degradation of lignin and growth of strain L1, multiple aspects of cells metabolism including transporter, environmental response factors, and protein synthesis were enhanced. Based on genome and proteomic analysis, at least four kinds of lignin degradation pathway might be present in strain L1, including a Gentisate pathway, the benzoic acid pathway and the

  9. Selective Oxidation of Lignin Model Compounds.

    Science.gov (United States)

    Gao, Ruili; Li, Yanding; Kim, Hoon; Mobley, Justin K; Ralph, John

    2018-05-02

    Lignin, the planet's most abundant renewable source of aromatic compounds, is difficult to degrade efficiently to welldefined aromatics. We developed a microwave-assisted catalytic Swern oxidation system using an easily prepared catalyst, MoO 2 Cl 2 (DMSO) 2 , and DMSO as the solvent and oxidant. It demonstrated high efficiency in transforming lignin model compounds containing the units and functional groups found in native lignins. The aromatic ring substituents strongly influenced the selectivity of β-ether phenolic dimer cleavage to generate sinapaldehyde and coniferaldehyde, monomers not usually produced by oxidative methods. Time-course studies on two key intermediates provided insight into the reaction pathway. Owing to the broad scope of this oxidation system and the insight gleaned with regard to its mechanism, this strategy could be adapted and applied in a general sense to the production of useful aromatic chemicals from phenolics and lignin. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Minimum Information about a Biosynthetic Gene cluster : commentary

    NARCIS (Netherlands)

    Medema, Marnix H; Kottmann, Renzo; Yilmaz, Pelin; Cummings, Matthew; Biggins, John B; Blin, Kai; de Bruijn, Irene; Chooi, Yit Heng; Claesen, Jan; Coates, R Cameron; Cruz-Morales, Pablo; Duddela, Srikanth; Dusterhus, Stephanie; Edwards, Daniel J; Fewer, David P; Garg, Neha; Geiger, Christoph; Gomez-Escribano, Juan Pablo; Greule, Anja; Hadjithomas, Michalis; Haines, Anthony S; Helfrich, Eric J N; Hillwig, Matthew L; Ishida, Keishi; Jones, Adam C; Jones, Carla S; Jungmann, Katrin; Kegler, Carsten; Kim, Hyun Uk; Kotter, Peter; Krug, Daniel; Masschelein, Joleen; Melnik, Alexey V; Mantovani, Simone M; Monroe, Emily A; Moore, Marcus; Moss, Nathan; Nutzmann, Hans-Wilhelm; Pan, Guohui; Pati, Amrita; Petras, Daniel; Reen, F Jerry; Rosconi, Federico; Rui, Zhe; Tian, Zhenhua; Tobias, Nicholas J; Tsunematsu, Yuta; Wiemann, Philipp; Wyckoff, Elizabeth; Yan, Xiaohui; Yim, Grace; Yu, Fengan; Xie, Yunchang; Aigle, Bertrand; Apel, Alexander K; Balibar, Carl J; Balskus, Emily P; Barona-Gomez, Francisco; Bechthold, Andreas; Bode, Helge B; Borriss, Rainer; Brady, Sean F; Brakhage, Axel A; Caffrey, Patrick; Cheng, Yi-Qiang; Clardy, Jon; Cox, Russell J; De Mot, Rene; Donadio, Stefano; Donia, Mohamed S; van der Donk, Wilfred A; Dorrestein, Pieter C; Doyle, Sean; Driessen, Arnold J M; Ehling-Schulz, Monika; Entian, Karl-Dieter; Fischbach, Michael A; Gerwick, Lena; Gerwick, William H; Gross, Harald; Gust, Bertolt; Hertweck, Christian; Hofte, Monica; Jensen, Susan E; Ju, Jianhua; Katz, Leonard; Kaysser, Leonard; Klassen, Jonathan L; Keller, Nancy P; Kormanec, Jan; Kuipers, Oscar P; Kuzuyama, Tomohisa; Kyrpides, Nikos C; Kwon, Hyung-Jin; Lautru, Sylvie; Lavigne, Rob; Lee, Chia Y; Linquan, Bai; Liu, Xinyu; Liu, Wen; Luzhetskyy, Andriy; Mahmud, Taifo; Mast, Yvonne; Mendez, Carmen; Metsa-Ketela, Mikko; Micklefield, Jason; Mitchell, Douglas A; Moore, Bradley S; Moreira, Leonilde M; Muller, Rolf; Neilan, Brett A; Nett, Markus; Nielsen, Jens; O'Gara, Fergal; Oikawa, Hideaki; Osbourn, Anne; Osburne, Marcia S; Ostash, Bohdan; Payne, Shelley M; Pernodet, Jean-Luc; Petricek, Miroslav; Piel, Jorn; Ploux, Olivier; Raaijmakers, Jos M; Salas, Jose A; Schmitt, Esther K; Scott, Barry; Seipke, Ryan F; Shen, Ben; Sherman, David H; Sivonen, Kaarina; Smanski, Michael J; Sosio, Margherita; Stegmann, Evi; Sussmuth, Roderich D; Tahlan, Kapil; Thomas, Christopher M; Tang, Yi; Truman, Andrew W; Viaud, Muriel; Walton, Jonathan D; Walsh, Christopher T; Weber, Tilmann; van Wezel, Gilles P; Wilkinson, Barrie; Willey, Joanne M; Wohlleben, Wolfgang; Wright, Gerard D; Ziemert, Nadine; Zhang, Changsheng; Zotchev, Sergey B; Breitling, Rainer; Takano, Eriko; Glockner, Frank Oliver

    A wide variety of enzymatic pathways that produce specialized metabolites in bacteria, fungi and plants are known to be encoded in biosynthetic gene clusters. Information about these clusters, pathways and metabolites is currently dispersed throughout the literature, making it difficult to exploit.

  11. Engineering of the aspartate family biosynthetic pathway in barley (Hordeum vulgare L.) by transformation with heterologous genes encoding feed-back-insensitive aspartate kinase and dihydrodipicolinate synthase

    DEFF Research Database (Denmark)

    Brinch-Pedersen, H.; Galili, G.; Sørensen, K.

    1996-01-01

    In prokaryotes and plants the synthesis of the essential amino acids lysine and threonine is predominantly regulated by feed-back inhibition of aspartate kinase (AK) and dihydrodipicolinate synthase (DHPS). In order to modify the flux through the aspartate family pathway in barley and enhance...... the accumulation of the corresponding amino acids, we have generated transgenic barley plants that constitutively express mutant Escherichia coli genes encoding lysine feed-back insensitive forms of AK and DHPS. As a result, leaves of primary transformants (T0) exhibited a 14-fold increase of free lysine and an 8......, no differences were observed in the composition of total amino acids. The introduced genes were inherited in the T1 generation where enzymic activities revealed a 2.3-fold increase of AK activity and a 4.0-9.5-fold increase for DHPS. T1 seeds of DHPS transformants showed the same changes in free amino acids...

  12. Analytical methodology for sulfonated lignins

    NARCIS (Netherlands)

    Brudin, S.; Schoenmakers, P.

    2010-01-01

    There is a significant need to characterize and classify lignins and sulfonated lignins. Lignins have so far received a good deal of attention, whereas this is not true for sulfonated lignins. There is a clear demand for a better understanding of sulfonated lignins on a chemical as well as physical

  13. [Polyketone Reaction in Biosynthetic Pathways of 2, 3, 5, 4'-Tetrahydroxy Stilhene-2-O-β-D-glucoside in Polygonum multiflorum by Biocatalysis].

    Science.gov (United States)

    Lei, Lei; Xia, Wan-xia; Shao, Li; Zhao, Shu-jin

    2015-10-01

    2, 3, 5, 4'-Tetrahydroxy stilbene-2-O-β-D-glucoside (THSG), the active ingredient of Polygonum multiflorum, its polyketone reaction in the biosynthesis pathways was studied by biocatalysis method. The substrates 4-coumaroyl-CoA and malonyl-CoA were catalyzed in vitro by the crude enzyme extracted from Polygonum multiflorum callus, then the products were verified by HPLC and LC-MS methods. And the crude enzyme was analyzed by ammonium sulfate precipitation method and SDS-PAGE. HPLC chromatogram showed the same retention time of both the product and resveratrol standards; LC-MS spectra showed that the m/z of product was 227, which was consistent with resveratrol standards under the mode of negative ion; Ammonium sulfate (AS) precipitation method showed AS of 40% - 70% had catalytic activity,and 50% - 60% was the optimum; SDS-PAGE showed protein bands were obviously different among different AS concentration between 20% - 80%, the protein band of 42 kDa was found in AS of 50% - 60%, which had the same molecular weight with stilbene synthase. The product of polyketone reaction in the biosynthesis of THSG is resveratrol rather than THSG, so it is speculated that THSG is the conversion product of resveratrol instead of the direct product of the polyketone reaction.

  14. Bacteria and lignin degradation

    Institute of Scientific and Technical Information of China (English)

    Jing LI; Hongli YUAN; Jinshui YANG

    2009-01-01

    Lignin is both the most abundant aromatic (phenolic) polymer and the second most abundant raw material.It is degraded and modified by bacteria in the natural world,and bacteria seem to play a leading role in decomposing lignin in aquatic ecosystems.Lignin-degrading bacteria approach the polymer by mechanisms such as tunneling,erosion,and cavitation.With the advantages of immense environmental adaptability and biochemical versatility,bacteria deserve to be studied for their ligninolytic potential.

  15. Enterobacter sp. I-3, a bio-herbicide inhibits gibberellins biosynthetic pathway and regulates abscisic acid and amino acids synthesis to control plant growth.

    Science.gov (United States)

    Radhakrishnan, Ramalingam; Park, Jae-Man; Lee, In-Jung

    2016-12-01

    Very few bacterial species were identified as bio-herbicides for weed control. The present research was focused to elucidate the plant growth retardant properties of Enterobacter sp. I-3 during their interaction by determining the changes in endogenous photosynthetic pigments, plant hormones and amino acids. The two bacterial isolates I-4-5 and I-3 were used to select the superior bacterium for controlling weed seeds (Echinochloa crus-galli L. and Portulaca oleracea L.) germination. The post-inoculation of I-3 (Enterobacter sp. I-3) significantly inhibited the weeds seed germination than their controls. The mechanism of bacterium induced plant growth reduction was identified in lettuce treated with I-3 bacterium and compared their effects with known chemical herbicide, trinexapac-ethyl (TE). The treatment of I-3 and TE showed a significant inhibitory effect on shoot length, leaf number, leaf length, leaf width, shoot weight, root weight and chlorophyll content in lettuce seedlings. The endogenous gibberellins (GAs) and abscisic acid (ABA) analysis showed that Enterobacter sp. I-3 treated plants had lower levels of GAs (GA 12 , GA 19 , GA 20 and GA 8 ) and GAs/ABA ratio and then, the higher level of ABA when compared to their controls. Indeed, the individual amino acids ie., aspartic acid, glutamic acid, glycine, threonine, alanine, serine, leucine, isoleucine and tyrosine were declined in TE and I-3 exposed plants. Our results suggest that the utilization of Enterobacter sp. I-3 inhibits the GAs pathway and amino acids synthesis in weeds to control their growth can be an alternative to chemical herbicides. Copyright © 2016 Elsevier GmbH. All rights reserved.

  16. The crystal structure of the bifunctional deaminase/reductase RibD of the riboflavin biosynthetic pathway in Escherichia coli: implications for the reductive mechanism.

    Science.gov (United States)

    Stenmark, Pål; Moche, Martin; Gurmu, Daniel; Nordlund, Pär

    2007-10-12

    We have determined the crystal structure of the bi-functional deaminase/reductase enzyme from Escherichia coli (EcRibD) that catalyzes two consecutive reactions during riboflavin biosynthesis. The polypeptide chain of EcRibD is folded into two domains where the 3D structure of the N-terminal domain (1-145) is similar to cytosine deaminase and the C-terminal domain (146-367) is similar to dihydrofolate reductase. We showed that EcRibD is dimeric and compared our structure to tetrameric RibG, an ortholog from Bacillus subtilis (BsRibG). We have also determined the structure of EcRibD in two binary complexes with the oxidized cofactor (NADP(+)) and with the substrate analogue ribose-5-phosphate (RP5) and superposed these two in order to mimic the ternary complex. Based on this superposition we propose that the invariant Asp200 initiates the reductive reaction by abstracting a proton from the bound substrate and that the pro-R proton from C4 of the cofactor is transferred to C1 of the substrate. A highly flexible loop is found in the reductase active site (159-173) that appears to control cofactor and substrate binding to the reductase active site and was therefore compared to the corresponding Met20 loop of E. coli dihydrofolate reductase (EcDHFR). Lys152, identified by comparing substrate analogue (RP5) coordination in the reductase active site of EcRibD with the homologous reductase from Methanocaldococcus jannaschii (MjaRED), is invariant among bacterial RibD enzymes and could contribute to the various pathways taken during riboflavin biosynthesis in bacteria and yeast.

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

    Science.gov (United States)

    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. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  19. De novo transcriptome sequencing and digital gene expression analysis predict biosynthetic pathway of rhynchophylline and isorhynchophylline from Uncaria rhynchophylla, a non-model plant with potent anti-alzheimer's properties.

    Science.gov (United States)

    Guo, Qianqian; Ma, Xiaojun; Wei, Shugen; Qiu, Deyou; Wilson, Iain W; Wu, Peng; Tang, Qi; Liu, Lijun; Dong, Shoukun; Zu, Wei

    2014-08-12

    The major medicinal alkaloids isolated from Uncaria rhynchophylla (gouteng in chinese) capsules are rhynchophylline (RIN) and isorhynchophylline (IRN). Extracts containing these terpene indole alkaloids (TIAs) can inhibit the formation and destabilize preformed fibrils of amyloid β protein (a pathological marker of Alzheimer's disease), and have been shown to improve the cognitive function of mice with Alzheimer-like symptoms. The biosynthetic pathways of RIN and IRN are largely unknown. In this study, RNA-sequencing of pooled Uncaria capsules RNA samples taken at three developmental stages that accumulate different amount of RIN and IRN was performed. More than 50 million high-quality reads from a cDNA library were generated and de novo assembled. Sequences for all of the known enzymes involved in TIAs synthesis were identified. Additionally, 193 cytochrome P450 (CYP450), 280 methyltransferase and 144 isomerase genes were identified, that are potential candidates for enzymes involved in RIN and IRN synthesis. Digital gene expression profile (DGE) analysis was performed on the three capsule developmental stages, and based on genes possessing expression profiles consistent with RIN and IRN levels; four CYP450s, three methyltransferases and three isomerases were identified as the candidates most likely to be involved in the later steps of RIN and IRN biosynthesis. A combination of de novo transcriptome assembly and DGE analysis was shown to be a powerful method for identifying genes encoding enzymes potentially involved in the biosynthesis of important secondary metabolites in a non-model plant. The transcriptome data from this study provides an important resource for understanding the formation of major bioactive constituents in the capsule extract from Uncaria, and provides information that may aid in metabolic engineering to increase yields of these important alkaloids.

  20. Biotechnological modification of lignin

    Energy Technology Data Exchange (ETDEWEB)

    1989-01-01

    A literature search of organisms capable of degrading lignin was conducted. Four fungi were selected for study and these were Phanerochaete chrysosporium, Chrysosporium pruinosum, Phlebia tremellosus and Trametes versicolor. Other organisms, Pleurotus ostreatus, Pleurotus florida and Lentinus edodes were also tested in preliminary experiments. All cultures were screened for their ability to degrade the lignin component of aspen sawdust and also lignin extracted from steam-exploded wood. This type of screen was followed by analysis of culture filtrates for the presence of ligninase, the marker enzyme for lignin degradation. Phanerochaete chrysosporium and consequently chosen for further studies in fermentors. Considerable efforts were directed to production of ligninase in fermentors. Only when Chrysosporium pruinosum was pre-cultured in a shake flask for 4 days and then transferred to a fermentor could ligninase activity be detected. The enzyme from shake flasks has been concentrated ready for use in bench-scale studies on cell-free depolymerization of lignin. 13 refs., 8 tabs.

  1. Syngenomics Applied to the Tryptophan Biosynthetic Pathway

    National Research Council Canada - National Science Library

    Miller, Jeffrey

    2002-01-01

    .... We have identified genes from Lactococcus lactis and Pseudomonas aeruginosa that cause mutator phenotypes when overexpressed in E. coli and interestingly, one of these encodes a regulator for multiple drug resistance.

  2. Expression profile of genes coding for carotenoid biosynthetic ...

    Indian Academy of Sciences (India)

    Expression profile of genes coding for carotenoid biosynthetic pathway during ripening and their association with accumulation of lycopene in tomato fruits. Shuchi Smita, Ravi Rajwanshi, Sangram Keshari Lenka, Amit Katiyar, Viswanathan Chinnusamy and. Kailash Chander Bansal. J. Genet. 92, 363–368. Table 1.

  3. Production of Flocculants, Adsorbents, and Dispersants from Lignin.

    Science.gov (United States)

    Chen, Jiachuan; Eraghi Kazzaz, Armin; AlipoorMazandarani, Niloofar; Hosseinpour Feizi, Zahra; Fatehi, Pedram

    2018-04-10

    Currently, lignin is mainly produced in pulping processes, but it is considered as an under-utilized chemical since it is being mainly used as a fuel source. Lignin contains many hydroxyl groups that can participate in chemical reactions to produce value-added products. Flocculants, adsorbents, and dispersants have a wide range of applications in industry, but they are mainly oil-based chemicals and expensive. This paper reviews the pathways to produce water soluble lignin-based flocculants, adsorbents, and dispersants. It provides information on the recent progress in the possible use of these lignin-based flocculants, adsorbents, and dispersants. It also critically discusses the advantages and disadvantages of various approaches to produce such products. The challenges present in the production of lignin-based flocculants, adsorbents, and dispersants and possible scenarios to overcome these challenges for commercial use of these products in industry are discussed.

  4. Production of Flocculants, Adsorbents, and Dispersants from Lignin

    Directory of Open Access Journals (Sweden)

    Jiachuan Chen

    2018-04-01

    Full Text Available Currently, lignin is mainly produced in pulping processes, but it is considered as an under-utilized chemical since it is being mainly used as a fuel source. Lignin contains many hydroxyl groups that can participate in chemical reactions to produce value-added products. Flocculants, adsorbents, and dispersants have a wide range of applications in industry, but they are mainly oil-based chemicals and expensive. This paper reviews the pathways to produce water soluble lignin-based flocculants, adsorbents, and dispersants. It provides information on the recent progress in the possible use of these lignin-based flocculants, adsorbents, and dispersants. It also critically discusses the advantages and disadvantages of various approaches to produce such products. The challenges present in the production of lignin-based flocculants, adsorbents, and dispersants and possible scenarios to overcome these challenges for commercial use of these products in industry are discussed.

  5. Unravelling Some of the Key Transformations in the Hydrothermal Liquefaction of Lignin.

    Science.gov (United States)

    Lui, Matthew Y; Chan, Bun; Yuen, Alexander K L; Masters, Anthony F; Montoya, Alejandro; Maschmeyer, Thomas

    2017-05-22

    Using both experimental and computational methods, focusing on intermediates and model compounds, some of the main features of the reaction mechanisms that operate during the hydrothermal processing of lignin were elucidated. Key reaction pathways and their connection to different structural features of lignin were proposed. Under neutral conditions, subcritical water was demonstrated to act as a bifunctional acid/base catalyst for the dissection of lignin structures. In a complex web of mutually dependent interactions, guaiacyl units within lignin were shown to significantly affect overall lignin reactivity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Reconstitution of Biosynthetic Machinery for the Synthesis of the Highly Elaborated Indole Diterpene Penitrem

    DEFF Research Database (Denmark)

    Liu, Chengwei; Tagami, Koichi; Minami, Atsushi

    2015-01-01

    KULNJ). Importantly, without conventional gene disruption, reconstitution of the biosynthetic machinery provided sufficient data to determine the pathway. It was thus demonstrated that the Aspergillus oryzae reconstitution system is a powerful method for studying the biosynthesis of complex natural products....

  7. Hydroxide catalysts for lignin depolymerization

    Energy Technology Data Exchange (ETDEWEB)

    Beckham, Gregg T.; Biddy, Mary J.; Chmely, Stephen C.; Sturgeon, Matthew

    2017-04-25

    Solid base catalysts and their use for the base-catalyzed depolymerization (BCD) of lignin to compounds such as aromatics are presented herein. Exemplary catalysts include layered double hydroxides (LDHs) as recyclable, heterogeneous catalysts for BCD of lignin.

  8. Hydroxide catalysts for lignin depolymerization

    Science.gov (United States)

    Beckham, Gregg T; Biddy, Mary J.; Kruger, Jacob S.; Chmely, Stephen C.; Sturgeon, Matthew

    2017-10-17

    Solid base catalysts and their use for the base-catalyzed depolymerization (BCD) of lignin to compounds such as aromatics are presented herein. Exemplary catalysts include layered double hydroxides (LDHs) as recyclable, heterogeneous catalysts for BCD of lignin.

  9. Chapter 16: Lignin Visualization: Advanced Microscopy Techniques for Lignin Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Yining [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Donohoe, Bryon S [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-04-03

    Visualization of lignin in plant cell walls, with both spatial and chemical resolution, is emerging as an important tool to understand lignin's role in the plant cell wall's nanoscale architecture and to understand and design processes intended to modify the lignin. As such, this chapter reviews recent advances in advanced imaging methods with respect to lignin in plant cell walls. This review focuses on the importance of lignin detection and localization for studies in both plant biology and biotechnology. Challenges going forward to identify and delineate lignin from other plant cell wall components and to quantitatively analyze lignin in whole cell walls from native plant tissue and treated biomass are also discussed.

  10. Comparison studies on soda lignin and soda-anthraquinone lignin

    International Nuclear Information System (INIS)

    Ibrahim, M.N.M; Yusof, N.N.M.; Hashim, A.

    2007-01-01

    Soda lignin and soda anthraquinone lignin were compared in this study. The physico-chemical properties and structural features of the isolated lignin were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet (UV), ash test, Carbon-Hydrogen-Nitrogen (CHN) analyzer, Nuclear Magnetic Resonance ( 13 C-NMR) and High Performance Liquid Chromatography (HPLC). Nitrobenzene oxidation was performed on these two types of lignin especially for the HPLC analysis. Based on the CHN, 13 C-NMR and UV results there were no significant differences between soda lignin and soda anthraquinone lignin. The FTIR results also showed that there were no significant differences in terms of functional groups that exist in both lignins. (author)

  11. NMR of lignins

    Science.gov (United States)

    John Ralph; Larry L. Landucci

    2010-01-01

    This chapter will consider the basic aspects and findings of several forms of NMR spectroscopy, including separate discussions of proton, carbon, heteronuclear, and multidimensional NMR. Enhanced focus will be on 13C NMR, because of its qualitative and quantitative importance, followed by NMR’s contributions to our understanding of lignin...

  12. Lignin blockers and uses thereof

    Science.gov (United States)

    Yang, Bin [West Lebanon, NH; Wyman, Charles E [Norwich, VT

    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.

  13. Heterologous expression of pikromycin biosynthetic gene cluster using Streptomyces artificial chromosome system.

    Science.gov (United States)

    Pyeon, Hye-Rim; Nah, Hee-Ju; Kang, Seung-Hoon; Choi, Si-Sun; Kim, Eung-Soo

    2017-05-31

    Heterologous expression of biosynthetic gene clusters of natural microbial products has become an essential strategy for titer improvement and pathway engineering of various potentially-valuable natural products. A Streptomyces artificial chromosomal conjugation vector, pSBAC, was previously successfully applied for precise cloning and tandem integration of a large polyketide tautomycetin (TMC) biosynthetic gene cluster (Nah et al. in Microb Cell Fact 14(1):1, 2015), implying that this strategy could be employed to develop a custom overexpression scheme of natural product pathway clusters present in actinomycetes. To validate the pSBAC system as a generally-applicable heterologous overexpression system for a large-sized polyketide biosynthetic gene cluster in Streptomyces, another model polyketide compound, the pikromycin biosynthetic gene cluster, was preciously cloned and heterologously expressed using the pSBAC system. A unique HindIII restriction site was precisely inserted at one of the border regions of the pikromycin biosynthetic gene cluster within the chromosome of Streptomyces venezuelae, followed by site-specific recombination of pSBAC into the flanking region of the pikromycin gene cluster. Unlike the previous cloning process, one HindIII site integration step was skipped through pSBAC modification. pPik001, a pSBAC containing the pikromycin biosynthetic gene cluster, was directly introduced into two heterologous hosts, Streptomyces lividans and Streptomyces coelicolor, resulting in the production of 10-deoxymethynolide, a major pikromycin derivative. When two entire pikromycin biosynthetic gene clusters were tandemly introduced into the S. lividans chromosome, overproduction of 10-deoxymethynolide and the presence of pikromycin, which was previously not detected, were both confirmed. Moreover, comparative qRT-PCR results confirmed that the transcription of pikromycin biosynthetic genes was significantly upregulated in S. lividans containing tandem

  14. Efficient, environmentally-friendly and specific valorization of lignin: promising role of non-radical lignolytic enzymes.

    Science.gov (United States)

    Wang, Wenya; Zhang, Chao; Sun, Xinxiao; Su, Sisi; Li, Qiang; Linhardt, Robert J

    2017-06-01

    Lignin is the second most abundant bio-resource in nature. It is increasingly important to convert lignin into high value-added chemicals to accelerate the development of the lignocellulose biorefinery. Over the past several decades, physical and chemical methods have been widely explored to degrade lignin and convert it into valuable chemicals. Unfortunately, these developments have lagged because of several difficulties, of which high energy consumption and non-specific cleavage of chemical bonds in lignin remain the greatest challenges. A large number of enzymes have been discovered for lignin degradation and these are classified as radical lignolytic enzymes and non-radical lignolytic enzymes. Radical lignolytic enzymes, including laccases, lignin peroxidases, manganese peroxidases and versatile peroxidases, are radical-based bio-catalysts, which degrade lignins through non-specific cleavage of chemical bonds but can also catalyze the radical-based re-polymerization of lignin fragments. In contrast, non-radical lignolytic enzymes selectively cleave chemical bonds in lignin and lignin model compounds and, thus, show promise for use in the preparation of high value-added chemicals. In this mini-review, recent developments on non-radical lignolytic enzymes are discussed. These include recently discovered non-radical lignolytic enzymes, their metabolic pathways for lignin conversion, their recent application in the lignin biorefinery, and the combination of bio-catalysts with physical/chemical methods for industrial development of the lignin refinery.

  15. Regulation of Flavonoid Biosynthetic Genes in Germinating Arabidopsis Seedlings.

    Science.gov (United States)

    Kubasek, WL; Shirley, BW; McKillop, A; Goodman, HM; Briggs, W; Ausubel, FM

    1992-01-01

    Many higher plants, including Arabidopsis, transiently display purple anthocyanin pigments just after seed germination. We observed that steady state levels of mRNAs encoded by four flavonoid biosynthetic genes, PAL1 (encoding phenylalanine ammonia-lyase 1), CHS (encoding chalcone synthase), CHI (encoding chalcone isomerase), and DFR (encoding dihydroflavonol reductase), were temporally regulated, peaking in 3-day-old seedlings grown in continuous white light. Except for the case of PAL1 mRNA, mRNA levels for these flavonoid genes were very low in seedlings grown in darkness. Light induction studies using seedlings grown in darkness showed that PAL1 mRNA began to accumulate before CHS and CHI mRNAs, which, in turn, began to accumulate before DFR mRNA. This order of induction is the same as the order of the biosynthetic steps in flavonoid biosynthesis. Our results suggest that the flavonoid biosynthetic pathway is coordinately regulated by a developmental timing mechanism during germination. Blue light and UVB light induction experiments using red light- and dark-grown seedlings showed that the flavonoid biosynthetic genes are induced most effectively by UVB light and that blue light induction is mediated by a specific blue light receptor. PMID:12297632

  16. Accumulation of Rutin and Betulinic Acid and Expression of Phenylpropanoid and Triterpenoid Biosynthetic Genes in Mulberry (Morus alba L.).

    Science.gov (United States)

    Zhao, Shicheng; Park, Chang Ha; Li, Xiaohua; Kim, Yeon Bok; Yang, Jingli; Sung, Gyoo Byung; Park, Nam Il; Kim, Soonok; Park, Sang Un

    2015-09-30

    Mulberry (Morus alba L.) is used in traditional Chinese medicine and is the sole food source of the silkworm. Here, 21 cDNAs encoding phenylpropanoid biosynthetic genes and 21 cDNAs encoding triterpene biosynthetic genes were isolated from mulberry. The expression levels of genes involved in these biosynthetic pathways and the accumulation of rutin, betulin, and betulinic acid, important secondary metabolites, were investigated in different plant organs. Most phenylpropanoid and triterpene biosynthetic genes were highly expressed in leaves and/or fruit, and most genes were downregulated during fruit ripening. The accumulation of rutin was more than fivefold higher in leaves than in other organs, and higher levels of betulin and betulinic acid were found in roots and leaves than in fruit. By comparing the contents of these compounds with gene expression levels, we speculate that MaUGT78D1 and MaLUS play important regulatory roles in the rutin and betulin biosynthetic pathways.

  17. Lignin-Furfural Based Adhesives

    OpenAIRE

    Dongre, Prajakta; Driscoll, Mark; Amidon, Thomas; Bujanovic, Biljana

    2015-01-01

    Lignin recovered from the hot-water extract of sugar maple ( Acer saccharum ) is used in this study to synthesize adhesive blends to replace phenol-formaldehyde (PF) resin. Untreated lignin is characterized by lignin content and nuclear magnetic resonance (NMR) analysis. The molecular weight distribution of the lignin and the blends are characterized by size exclusion chromatography (SEC). The effect of pH (0.3, 0.65 and 1), ex situ furfural, and curing conditions on the tensile properties of...

  18. Peracetic Acid Depolymerization of Biorefinery Lignin for Production of Selective Monomeric Phenolic Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ruoshui [Voiland School of Chemical Engineering and Bioengineering, Bioproducts, Science & Engineering Laboratory, Washington State University, 2710 Crimson Way Richland WA 99354 USA; Guo, Mond [Voiland School of Chemical Engineering and Bioengineering, Bioproducts, Science & Engineering Laboratory, Washington State University, 2710 Crimson Way Richland WA 99354 USA; Lin, Kuan-ting [Voiland School of Chemical Engineering and Bioengineering, Bioproducts, Science & Engineering Laboratory, Washington State University, 2710 Crimson Way Richland WA 99354 USA; Hebert, Vincent R. [Food and Environmental Laboratory, Washington State, University-TriCities, 2710 Crimson Way Richland WA 99354 USA; Zhang, Jinwen [Wood Materials and Engineering Laboratory, Washington State University, Pullman WA 99164 USA; Wolcott, Michael P. [Wood Materials and Engineering Laboratory, Washington State University, Pullman WA 99164 USA; Quintero, Melissa [Voiland School of Chemical Engineering and Bioengineering, Bioproducts, Science & Engineering Laboratory, Washington State University, 2710 Crimson Way Richland WA 99354 USA; Ramasamy, Karthikeyan K. [Chemical and Biological Process Development Group, Pacific Northwest National Laboratory, Richland WA 99354 USA; Chen, Xiaowen [National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd Golden CO 80127 USA; Zhang, Xiao [Voiland School of Chemical Engineering and Bioengineering, Bioproducts, Science & Engineering Laboratory, Washington State University, 2710 Crimson Way Richland WA 99354 USA

    2016-07-04

    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.

  19. Peracetic Acid Depolymerization of Biorefinery Lignin for Production of Selective Monomeric Phenolic Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ruoshui [Voiland School of Chemical Engineering and Bioengineering, Bioproducts, Science & Engineering Laboratory, Washington State University, 2710 Crimson Way Richland WA 99354 USA; Guo, Mond [Voiland School of Chemical Engineering and Bioengineering, Bioproducts, Science & Engineering Laboratory, Washington State University, 2710 Crimson Way Richland WA 99354 USA; Lin, Kuan-ting [Voiland School of Chemical Engineering and Bioengineering, Bioproducts, Science & Engineering Laboratory, Washington State University, 2710 Crimson Way Richland WA 99354 USA; Hebert, Vincent R. [Food and Environmental Laboratory, Washington State, University-TriCities, 2710 Crimson Way Richland WA 99354 USA; Zhang, Jinwen [Wood Materials and Engineering Laboratory, Washington State University, Pullman WA 99164 USA; Wolcott, Michael P. [Wood Materials and Engineering Laboratory, Washington State University, Pullman WA 99164 USA; Quintero, Melissa [Voiland School of Chemical Engineering and Bioengineering, Bioproducts, Science & Engineering Laboratory, Washington State University, 2710 Crimson Way Richland WA 99354 USA; Ramasamy, Karthikeyan K. [Chemical and Biological Process Development Group, Pacific Northwest National Laboratory, Richland WA 99354 USA; Chen, Xiaowen [National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd Golden CO 80127 USA; Zhang, Xiao [Voiland School of Chemical Engineering and Bioengineering, Bioproducts, Science & Engineering Laboratory, Washington State University, 2710 Crimson Way Richland WA 99354 USA

    2016-07-04

    Lignin is the largest source of renewable material with an aromatic skeleton. However, due to the recalcitrant and heterogeneous nature of the lignin polymer as well as its complex side chain structures, 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) inclduing 4-hydroxy-2-methoxyphenol, p-hydroxybenzoic acid, vanillic acid, syringic acid, and 3,4-dihydroxybenzoic acid. The maximized MPCs 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.

  20. Peracetic Acid Depolymerization of Biorefinery Lignin for Production of Selective Monomeric Phenolic Compounds.

    Science.gov (United States)

    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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Disruption of Mediator rescues the stunted growth of a lignin-deficient Arabidopsis mutant.

    Science.gov (United States)

    Bonawitz, Nicholas D; Kim, Jeong Im; Tobimatsu, Yuki; Ciesielski, Peter N; Anderson, Nickolas A; Ximenes, Eduardo; Maeda, Junko; Ralph, John; Donohoe, Bryon S; Ladisch, Michael; Chapple, Clint

    2014-05-15

    Lignin is a phenylpropanoid-derived heteropolymer important for the strength and rigidity of the plant secondary cell wall. Genetic disruption of lignin biosynthesis has been proposed as a means to improve forage and bioenergy crops, but frequently results in stunted growth and developmental abnormalities, the mechanisms of which are poorly understood. Here we show that the phenotype of a lignin-deficient Arabidopsis mutant is dependent on the transcriptional co-regulatory complex, Mediator. Disruption of the Mediator complex subunits MED5a (also known as REF4) and MED5b (also known as RFR1) rescues the stunted growth, lignin deficiency and widespread changes in gene expression seen in the phenylpropanoid pathway mutant ref8, without restoring the synthesis of guaiacyl and syringyl lignin subunits. Cell walls of rescued med5a/5b ref8 plants instead contain a novel lignin consisting almost exclusively of p-hydroxyphenyl lignin subunits, and moreover exhibit substantially facilitated polysaccharide saccharification. These results demonstrate that guaiacyl and syringyl lignin subunits are largely dispensable for normal growth and development, implicate Mediator in an active transcriptional process responsible for dwarfing and inhibition of lignin biosynthesis, and suggest that the transcription machinery and signalling pathways responding to cell wall defects may be important targets to include in efforts to reduce biomass recalcitrance.

  2. Lignin derivatives from desilicated rice straw soda black liquor

    Energy Technology Data Exchange (ETDEWEB)

    El-Taraboulsi, M A; Nasser, M M

    1979-01-01

    Carboxymethyl lignin, cyanoethyl lignin, carboxyethyl lignin, and aminopropyl lignin were prepared from alkali lignin of rice straw black liquor (after disilication by storage for 1 wk to 1 yr) and used as sizes for paper, drilling fluid additives and flocculants.

  3. Syringyl lignin is unaltered by severe sinapyl alcohol dehydrogenase suppression in tobacco.

    Science.gov (United States)

    Barakate, Abdellah; Stephens, Jennifer; Goldie, Alison; Hunter, William N; Marshall, David; Hancock, Robert D; Lapierre, Catherine; Morreel, Kris; Boerjan, Wout; Halpin, Claire

    2011-12-01

    The manipulation of lignin could, in principle, facilitate efficient biofuel production from plant biomass. Despite intensive study of the lignin pathway, uncertainty exists about the enzyme catalyzing the last step in syringyl (S) monolignol biosynthesis, the reduction of sinapaldehyde to sinapyl alcohol. Traditional schemes of the pathway suggested that both guaiacyl (G) and S monolignols are produced by a single substrate-versatile enzyme, cinnamyl alcohol dehydrogenase (CAD). This was challenged by the discovery of a novel sinapyl alcohol dehydrogenase (SAD) that preferentially uses sinapaldehyde as a substrate and that was claimed to regulate S lignin biosynthesis in angiosperms. Consequently, most pathway schemes now show SAD (or SAD and CAD) at the sinapaldehyde reduction step, although functional evidence is lacking. We cloned SAD from tobacco (Nicotiana tabacum) and suppressed it in transgenic plants using RNA interference-inducing vectors. Characterization of lignin in the woody stems shows no change to content, composition, or structure, and S lignin is normal. By contrast, plants additionally suppressed in CAD have changes to lignin structure and S:G ratio and have increased sinapaldehyde in lignin, similar to plants suppressed in CAD alone. These data demonstrate that CAD, not SAD, is the enzyme responsible for S lignin biosynthesis in woody angiosperm xylem.

  4. Syringyl Lignin Is Unaltered by Severe Sinapyl Alcohol Dehydrogenase Suppression in Tobacco[W

    Science.gov (United States)

    Barakate, Abdellah; Stephens, Jennifer; Goldie, Alison; Hunter, William N.; Marshall, David; Hancock, Robert D.; Lapierre, Catherine; Morreel, Kris; Boerjan, Wout; Halpin, Claire

    2011-01-01

    The manipulation of lignin could, in principle, facilitate efficient biofuel production from plant biomass. Despite intensive study of the lignin pathway, uncertainty exists about the enzyme catalyzing the last step in syringyl (S) monolignol biosynthesis, the reduction of sinapaldehyde to sinapyl alcohol. Traditional schemes of the pathway suggested that both guaiacyl (G) and S monolignols are produced by a single substrate-versatile enzyme, cinnamyl alcohol dehydrogenase (CAD). This was challenged by the discovery of a novel sinapyl alcohol dehydrogenase (SAD) that preferentially uses sinapaldehyde as a substrate and that was claimed to regulate S lignin biosynthesis in angiosperms. Consequently, most pathway schemes now show SAD (or SAD and CAD) at the sinapaldehyde reduction step, although functional evidence is lacking. We cloned SAD from tobacco (Nicotiana tabacum) and suppressed it in transgenic plants using RNA interference–inducing vectors. Characterization of lignin in the woody stems shows no change to content, composition, or structure, and S lignin is normal. By contrast, plants additionally suppressed in CAD have changes to lignin structure and S:G ratio and have increased sinapaldehyde in lignin, similar to plants suppressed in CAD alone. These data demonstrate that CAD, not SAD, is the enzyme responsible for S lignin biosynthesis in woody angiosperm xylem. PMID:22158465

  5. Theoretical Approaches to Lignin Chemistry

    OpenAIRE

    Shevchenko, Sergey M.

    1994-01-01

    A critical review is presented of the applications of theoretical methods to the studies of the structure and chemical reactivity of lignin, including simulation of macromolecular properties, conformational calculations, quantum chemical analyses of electronic structure, spectra and chemical reactivity. Modern concepts of spatial organization and chemical reactivity of lignins are discussed.

  6. Syringyl lignin is unaltered by severe sinapyl alcohol dehydrogenase suppression in tobacco

    OpenAIRE

    Barakate, Abdellah; Stephens, Jennifer; Goldie, Alison; Hunter, William N.; Marshall, David; Hancock, Robert D.; Lapierre, Catherine; Morreele, Kris; Boerjane, Wout

    2011-01-01

    The manipulation of lignin could, in principle, facilitate efficient biofuel production from plant biomass. Despite intensive study of the lignin pathway, uncertainty exists about the enzyme catalyzing the last step in syringyl (S) monolignol biosynthesis, the reduction of sinapaldehyde to sinapyl alcohol. Traditional schemes of the pathway suggested that both guaiacyl (G) and S monolignols are produced by a single substrate-versatile enzyme, cinnamyl alcohol dehydrogenase (CAD). This was cha...

  7. Polymerization of different lignins by laccase

    NARCIS (Netherlands)

    Mattinen, M.L.; Suortti, T.; Gosselink, R.J.A.; Argyropoulos, D.S.; Evtuguin, D.; Suurnäkki, A.; Jong, de E.; Tamminen, T.

    2008-01-01

    In this study the oxidative polymerization of different lignins, i.e. Flax Soda lignin, Spruce EMAL, and Eucalyptus Dioxane lignin by Trametes hirsuta laccase was compared. Initially the structures of the different lignins were compared by Fourier transform infrared spectroscopy. The reactivity of

  8. Raman spectra of lignin model compounds

    Science.gov (United States)

    Umesh P. Agarwal; Richard S. Reiner; Ashok K. Pandey; Sally A. Ralph; Kolby C. Hirth; Rajai H. Atalla

    2005-01-01

    To fully exploit the value of Raman spectroscopy for analyzing lignins and lignin containing materials, a detailed understanding of lignins’ Raman spectra needs to be achieved. Although advances made thus far have led to significant growth in application of Raman techniques, further developments are needed to improve upon the existing knowledge. Considering that lignin...

  9. Lignin valorization through integrated biological funneling and chemical catalysis

    Science.gov (United States)

    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

  10. Characterization of a SAM-dependent fluorinase from a latent biosynthetic pathway for fluoroacetate and 4-fluorothreonine formation in Nocardia brasiliensis [v1; ref status: indexed, http://f1000r.es/2tz

    Directory of Open Access Journals (Sweden)

    Yaya Wang

    2014-02-01

    Full Text Available Fluorination has been widely used in chemical synthesis, but is rare in nature. The only known biological fluorination scope is represented by the fl pathway from Streptomyces cattleya that produces fluoroacetate (FAc and 4-fluorothreonine (4-FT. Here we report the identification of a novel pathway for FAc and 4-FT biosynthesis from the actinomycetoma-causing pathogen Nocardia brasiliensis ATCC 700358. The new pathway shares overall conservation with the fl pathway in S. cattleya. Biochemical characterization of the conserved domains revealed a novel fluorinase NobA that can biosynthesize 5’-fluoro-5’-deoxyadenosine (5’-FDA from inorganic fluoride and S-adenosyl-l-methionine (SAM. The NobA shows similar halide specificity and characteristics to the fluorination enzyme FlA of the fl pathway. Kinetic parameters for fluoride (Km 4153 μM, kcat 0.073 min-1 and SAM (Km 416 μM, kcat 0.139 min-1 have been determined, revealing that NobA is slightly (2.3 fold slower than FlA. Upon sequence comparison, we finally identified a distinct loop region in the fluorinases that probably accounts for the disparity of fluorination activity.

  11. Lignin-Furfural Based Adhesives

    Directory of Open Access Journals (Sweden)

    Prajakta Dongre

    2015-07-01

    Full Text Available Lignin recovered from the hot-water extract of sugar maple (Acer saccharum is used in this study to synthesize adhesive blends to replace phenol-formaldehyde (PF resin. Untreated lignin is characterized by lignin content and nuclear magnetic resonance (NMR analysis. The molecular weight distribution of the lignin and the blends are characterized by size exclusion chromatography (SEC. The effect of pH (0.3, 0.65 and 1, ex situ furfural, and curing conditions on the tensile properties of adhesive reinforced glass fibers is determined and compared to the reinforcement level of commercially available PF resin. The adhesive blend prepared at pH = 0.65 with no added furfural exhibits the highest tensile properties and meets 90% of the PF tensile strength.

  12. Lignin-degrading enzyme activities.

    Science.gov (United States)

    Chen, Yi-ru; Sarkanen, Simo; Wang, Yun-Yan

    2012-01-01

    Over the past three decades, the activities of four kinds of enzyme have been purported to furnish the mechanistic foundations for macromolecular lignin depolymerization in decaying plant cell walls. The pertinent fungal enzymes comprise lignin peroxidase (with a relatively high redox potential), manganese peroxidase, an alkyl aryl etherase, and laccase. The peroxidases and laccase, but not the etherase, are expressed extracellularly by white-rot fungi. A number of these microorganisms exhibit a marked preference toward lignin in their degradation of lignocellulose. Interestingly, some white-rot fungi secrete both kinds of peroxidase but no laccase, while others that are equally effective express extracellular laccase activity but no peroxidases. Actually, none of these enzymes has been reported to possess significant depolymerase activity toward macromolecular lignin substrates that are derived with little chemical modification from the native biopolymer. Here, the assays commonly employed for monitoring the traditional fungal peroxidases, alkyl aryl etherase, and laccase are described in their respective contexts. A soluble native polymeric substrate that can be isolated directly from a conventional milled-wood lignin preparation is characterized in relation to its utility in next-generation lignin-depolymerase assays.

  13. Biomimetic cell wall model studies to identify new lignin bioengineering targets for improving biomass susceptibility to pretreatment and enzymatic saccharification

    Science.gov (United States)

    Increasingly, bioengineering of lignin to contain atypical building blocks from other metabolic pathways is being pursued to custom-design lignin that is easier to remove by chemical pretreatments and less inhibitory toward polysaccharide saccharification. Because plants produce such a diverse array...

  14. Characterization and engineering of thermophilic aldolases : synthesizing nitrogen-heterocycles in biosynthetic routes

    NARCIS (Netherlands)

    Wolterink-van Loo, S.

    2009-01-01

    Aldolases are enzymes that catalyze reactions in both degradation and biosynthetic pathways in vivo and have been discovered in all domains of life. they. An interesting property of aldolases is that they can synthesize carbon-carbon bonds, generating a new stereogenic centre. As enzymes are

  15. Evidence supporting dissimilatory and assimilatory lignin degradation in Enterobacter lignolyticus SCF1

    Energy Technology Data Exchange (ETDEWEB)

    DeAngelis, Kristen M.; Sharma, Deepak; Varney, Rebecca; Simmons, Blake A.; Isern, Nancy G.; Markillie, Lye Meng; Nicora, Carrie D.; Norbeck, Angela D.; Taylor, Ronald C.; Aldrich, Joshua T.; Robinson, Errol W.

    2013-08-29

    The anaerobic isolate Enterobacter lignolyticus SCF1 was initially cultivated based on anaerobic growth on lignin as sole carbon source. The source of the isolated bacteria was from tropical forest soils that decompose litter rapidly with low and fluctuating redox potentials, making it likely that bacteria using oxygen-independent enzymes play an important role in decomposition. We have examined differential expression of the anaerobic isolate Enterobacter lignolyticus SCF1 during growth on lignin. After 48 hours of growth, we used transcriptomics and proteomics to define the enzymes and other regulatory machinery that these organisms use to degrade lignin, as well as metabolomics to measure lignin degradation and monitor the use of lignin and iron as terminal electron acceptors that facilitate more efficient use of carbon. Proteomics revealed accelerated xylose uptake and metabolism under lignin-amended growth, and lignin degradation via the 4-hydroxyphenylacetate degradation pathway, catalase/peroxidase enzymes, and the glutathione biosynthesis and glutathione S-transferase proteins. We also observed increased production of NADH-quinone oxidoreductase, other electron transport chain proteins, and ATP synthase and ATP-binding cassette (ABC) transporters. Our data shows the advantages of a multi-omics approach, where incomplete pathways identified by genomics were completed, and new observations made on coping with poor carbon availability. The fast growth, high efficiency and specificity of enzymes employed in bacterial anaerobic litter deconstruction makes these soils useful templates for improving biofuel production.

  16. Pyrolysis - gas chromatography - mass spectrometry of lignins

    Energy Technology Data Exchange (ETDEWEB)

    Martin, F; Saiz-Jimenez, C; Gonzalez-Vila, F J

    1979-01-01

    Milled wood lignins from spruce, beech and bamboo were pyrolysed. The high-boiling products of pyrolysis were studied by GLC and mass spectrometry. The forty-three products identified provide information on the structural units of lignin.

  17. Lignin poly(lactic acid) copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Olsson, Johan Vilhelm; Chung, Yi-Lin; Li, Russell Jingxian; Waymouth, Robert; Sattely, Elizabeth; Billington, Sarah; Frank, Curtis W.

    2017-02-14

    Provided herein are graft co-polymers of lignin and poly(lactic acid) (lignin-g-PLA copolymer), thermoset and thermoplastic polymers including them, methods of preparing these polymers, and articles of manufacture including such polymers.

  18. Lignin recovery. A resource to value

    International Nuclear Information System (INIS)

    Zimbardi, P.; Cardinale, G.; Demichele, M.; Nanna, F.; Viggiano, D.; Bonini, C.; D'Alessio, L.; D'Auria, M.; Teghil, R.; Tofani, D.

    1999-01-01

    In the present paper, the effects of the steam explosion (ES) pretreatment conditions on recovery and chemical structure of wheat straw lignin are reported. The experimental data of lignin recovery by caustic extraction, followed by acid precipitation, have been interpolated to obtain the dependence on the time and temperature of SE. The lignin has been characterised by using several methods. Preliminary results on the synthesis of copolymers lignin-styrene are also reported [it

  19. Lignin biopolymer based triboelectric nanogenerators

    Science.gov (United States)

    Bao, Yukai; Wang, Ruoxing; Lu, Yunmei; Wu, Wenzhuo

    2017-07-01

    Ongoing research in triboelectric nanogenerators (TENGs) focuses on increasing power generation, but obstacles concerning economical and eco-friendly utilization of TENGs continue to prevail. Being the second most abundant biopolymer on earth, lignin offers a valuable opportunity for low-cost TENG applications in biomedical devices, benefitting from its biodegradability and biocompatibility. Here, we develop for the first time a lignin biopolymer based TENGs for harvesting mechanical energy in the environment, which shows great potential for self-powered biomedical devices among other applications and opens doors to new technologies that utilize otherwise wasted materials for economically feasible and ecologically friendly production of energy devices.

  20. Structure variations of carbonizing lignin

    International Nuclear Information System (INIS)

    Otani, C.; Polidoro, H.A.; Otani, S.; Craievich, A.F.

    1984-01-01

    The studied lignin is a by-product of the process of ethanol production from eucaliptus. It was heat-treated under inert atmosphere conditions at increasing temperatures from 300C up to 2400C. The structural variations were studied by wide-angle X-ray diffraction, small-angle X-ray scattering and infrared absorption spectroscopy. The bulk and 'real' density of the compacted materials have also been determined as functions of the final temperature. These experimental results enabled us to establish a mechanism of structure variation based on the formation of a turbostratic graphite-like and porous structure within the initially amorphous lignin matrix. (Author) [pt

  1. Lignin pyrolysis for profitable lignocellulosic biorefineries

    NARCIS (Netherlands)

    Wild, de P.J.; Gosselink, R.J.A.; Huijgen, W.J.J.

    2014-01-01

    Bio-based industries (pulp and paper and biorefineries) produce > 50 Mt/yr of lignin that results from fractionation of lignocellulosic biomass. Lignin is world's second biopolymer and a major potential source for production of performance materials and aromatic chemicals. Lignin valorization is

  2. Cationic electrodepositable coating composition comprising lignin

    Science.gov (United States)

    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.

  3. Liquid Fuels from Lignins: Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    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.

  4. Converting lignin to aromatics: step by step

    NARCIS (Netherlands)

    Strassberger, Z.I.

    2014-01-01

    Lignin, the glue that holds trees together, is the most abundant natural resource of aromatics. In that respect, it is a far more advanced resource than crude oil. This is because lignin already contains the aromatic functional groups. Thus, catalytic conversion of lignin to high-value aromatics is

  5. Iron addition to soil specifically stabilized lignin

    Science.gov (United States)

    Steven J. Hall; Whendee L. Silver; Vitaliy I. Timokhin; Kenneth E. Hammel

    2016-01-01

    The importance of lignin as a recalcitrant constituent of soil organic matter (SOM) remains contested. Associations with iron (Fe) oxides have been proposed to specifically protect lignin from decomposition, but impacts of Fe-lignin interactions on mineralization rates remain unclear. Oxygen (O2) fluctuations characteristic of humid tropical...

  6. Recent development of antiSMASH and other computational approaches to mine secondary metabolite biosynthetic gene clusters

    DEFF Research Database (Denmark)

    Blin, Kai; Kim, Hyun Uk; Medema, Marnix H.

    2017-01-01

    Many drugs are derived from small molecules produced by microorganisms and plants, so-called natural products. Natural products have diverse chemical structures, but the biosynthetic pathways producing those compounds are often organized as biosynthetic gene clusters (BGCs) and follow a highly...... conserved biosynthetic logic. This allows for the identification of core biosynthetic enzymes using genome mining strategies that are based on the sequence similarity of the involved enzymes/genes. However, mining for a variety of BGCs quickly approaches a complexity level where manual analyses...... are no longer possible and require the use of automated genome mining pipelines, such as the antiSMASH software. In this review, we discuss the principles underlying the predictions of antiSMASH and other tools and provide practical advice for their application. Furthermore, we discuss important caveats...

  7. Laccase/Mediator Systems: Their Reactivity toward Phenolic Lignin Structures.

    Science.gov (United States)

    Hilgers, Roelant; Vincken, Jean-Paul; Gruppen, Harry; Kabel, Mirjam A

    2018-02-05

    Laccase-mediator systems (LMS) have been widely studied for their capacity to oxidize the nonphenolic subunits of lignin (70-90% of the polymer). The phenolic subunits (10-30% of the polymer), which can also be oxidized without mediators, have received considerably less attention. Consequently, it remains unclear to what extent the presence of a mediator influences the reactions of the phenolic subunits of lignin. To get more insight in this, UHPLC-MS was used to study the reactions of a phenolic lignin dimer (GBG), initiated by a laccase from Trametes versicolor , alone or in combination with the mediators HBT and ABTS. The role of HBT was negligible, as its oxidation by laccase occurred slowly in comparison to that of GBG. Laccase and laccase/HBT oxidized GBG at a comparable rate, resulting in extensive polymerization of GBG. In contrast, laccase/ABTS converted GBG at a higher rate, as GBG was oxidized both directly by laccase but also by ABTS radical cations, which were rapidly formed by laccase. The laccase/ABTS system resulted in Cα oxidation of GBG and coupling of ABTS to GBG, rather than polymerization of GBG. Based on these results, we propose reaction pathways of phenolic lignin model compounds with laccase/HBT and laccase/ABTS.

  8. Lignin-Based Materials Through Thiol-Maleimide "Click" Polymerization.

    Science.gov (United States)

    Buono, Pietro; Duval, Antoine; Averous, Luc; Habibi, Youssef

    2017-03-09

    In the present report an environmentally friendly approach to transforming renewable feedstocks into value-added materials is proposed. This transformation pathway was conducted under green conditions, without the use of solvents or catalyst. First, controlled modification of lignin, a major biopolymer present in wood and plants, was achieved by esterification with 11-maleimidoundecylenic acid (11-MUA), a derivative from castor oil that contains maleimide groups, following its transformation into 11-maleimidoundecanoyl chloride (11-MUC). Different degrees of substitution were achieved by using various amounts of the 11-MUC, leading to an efficient conversion of lignin hydroxy groups, as demonstrated by 1 H and 31 P NMR analyses. These fully biobased maleimide-lignin derivatives were subjected to an extremely fast (ca. 1 min) thiol-ene "click" polymerization with thiol-containing linkers. Aliphatic and aromatic thiol linkers bearing two to four thiol groups were used to tune the reactivity and crosslink density. The properties of the resulting materials were evaluated by swelling tests and thermal and mechanical analyses, which showed that varying the degree of functionality of the linker and the linker structure allowed accurate tailoring of the thermal and mechanical properties of the final materials, thus providing interesting perspectives for lignin in functional aromatic polymers. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Identifying new lignin bioengineering targets: 1. Monolignol-substitute impacts on lignin formation and cell wall fermentability

    Directory of Open Access Journals (Sweden)

    Lu Fachuang

    2010-06-01

    Full Text Available Abstract 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

  10. Lignin based controlled release coatings

    NARCIS (Netherlands)

    Mulder, W.J.; Gosselink, R.J.A.; Vingerhoeds, M.H.; Harmsen, P.F.H.; Eastham, D.

    2011-01-01

    Urea is a commonly used fertilizer. Due to its high water-solubility, misuse easily leads to excess nitrogen levels in the soil. The aim of this research was to develop an economically feasible and biodegradable slow-release coating for urea. For this purpose, lignin was selected as coating

  11. Lignin Sulfonation - A different Approach

    DEFF Research Database (Denmark)

    Bjørkmann, Anders

    2001-01-01

    The research on sulfite pulping has been characterized by the attempts to explain its chemistry. The. different approach presented is incited by perceptions about the (still) unsolved problem of the ultrastructural features of lignin in wood. A simple kinetic model has been chosen to describe the...

  12. Structural elucidation and antioxidant activity of lignin isolated from rice straw and alkali‑oxygen black liquor.

    Science.gov (United States)

    Jiang, Bo; Zhang, Yu; Gu, Lihui; Wu, Wenjuan; Zhao, Huifang; Jin, Yongcan

    2018-05-17

    Alkali‑oxygen cooking of lignocellulose offers lignin many structural properties and bioactivities for biorefinery. In this work, milled wood lignin (MWL) and alkali‑oxygen lignin (AOL) were isolated from rice straw and alkali‑oxygen black liquor, respectively. The lignin structure was characterized by spectroscopy and wet chemistry. Antioxidant activity of lignins was assessed by DPPH·and ABTS scavenging ability assay. Results showed the oxidization and condensation of lignin occurred during alkali‑oxygen cooking. The p-hydroxyphenyl was more easily removed from rice straw than guaiacyl and syringyl units. The ester or ether linkages derived from hydroxycynnamic acids, and the main interunit linkages, i.e. β-O-4' bonds, were mostly cleaved. Lignin-xylan complex had high reactivity under alkali‑oxygen condition. Tricin, incorporated into lignin, was detected in MWL but was absent in AOL. Nitrobenzene oxidation showed MWL can well represent the protolignin of rice straw, and the products yield decreased dramatically after alkali‑oxygen cooking. AOL had higher radical scavenging ability than MWL indicating alkali‑oxygen cooking was an effective pathway for the enhancement of antioxidant activity of lignin. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. On the biosynthetic origin of carminic acid

    DEFF Research Database (Denmark)

    Rasmussen, Silas A.; Kongstad, Kenneth T; Khorsand-Jamal, Paiman

    2018-01-01

    provides solid evidence of a polyketide, rather than a shikimate, origin of coccid pigments. Based on the newly identified compounds, we present a detailed biosynthetic scheme that accounts for the formation of carminic acid (CA) in D. coccus and all described coccid pigments which share a flavokermesic...... distribution suggests a common evolutionary origin for the trait in all coccid dye producing insect species....

  14. Lignin from Micro- to Nanosize: Applications

    Directory of Open Access Journals (Sweden)

    Stefan Beisl

    2017-11-01

    Full Text Available Micro- and nanosize lignin has recently gained interest due to improved properties compared to standard lignin available today. As the second most abundant biopolymer after cellulose, lignin is readily available but used for rather low-value applications. This review focuses on the application of micro- and nanostructured lignin in final products or processes that all show potential for high added value. The fields of application are ranging from improvement of mechanical properties of polymer nanocomposites, bactericidal and antioxidant properties and impregnations to hollow lignin drug carriers for hydrophobic and hydrophilic substances. Also, a carbonization of lignin nanostructures can lead to high-value applications such as use in supercapacitors for energy storage. The properties of the final product depend on the surface properties of the nanomaterial and, therefore, on factors like the lignin source, extraction method, and production/precipitation methods, as discussed in this review.

  15. Lignin biodegradation by the ascomycete Chrysonilia sitophila.

    Science.gov (United States)

    Rodríguez, J; Ferraz, A; Nogueira, R F; Ferrer, I; Esposito, E; Durán, N

    1997-01-01

    The lignin biodegradation process has an important role in the carbon cycle of the biosphere. The study of this natural process has developed mainly with the use of basidiomycetes in laboratory investigations. This has been a logical approach since most of the microorganisms involved in lignocellulosic degradation belong to this class of fungi. However, other microorganisms such as ascomycetes and also some bacteria, are involved in the lignin decaying process. This work focuses on lignin biodegradation by a microorganism belonging to the ascomycete class, Chrysonilia sitophila. Lignin peroxidase production and characterization, mechanisms of lignin degradation (lignin model compounds and lignin in wood matrix) and biosynthesis of veratryl alcohol are outstanding. Applications of C. sitophila for effluent treatment, wood biodegradation and single-cell protein production are also discussed.

  16. Identification of lignin genes and regulatory sequences involved in secondary cell wall formation in Acacia auriculiformis and Acacia mangium via de novo transcriptome sequencing

    Directory of Open Access Journals (Sweden)

    Cannon Charles H

    2011-07-01

    Full Text Available Abstract Background Acacia auriculiformis × Acacia mangium hybrids are commercially important trees for the timber and pulp industry in Southeast Asia. Increasing pulp yield while reducing pulping costs are major objectives of tree breeding programs. The general monolignol biosynthesis and secondary cell wall formation pathways are well-characterized but genes in these pathways are poorly characterized in Acacia hybrids. RNA-seq on short-read platforms is a rapid approach for obtaining comprehensive transcriptomic data and to discover informative sequence variants. Results We sequenced transcriptomes of A. auriculiformis and A. mangium from non-normalized cDNA libraries synthesized from pooled young stem and inner bark tissues using paired-end libraries and a single lane of an Illumina GAII machine. De novo assembly produced a total of 42,217 and 35,759 contigs with an average length of 496 bp and 498 bp for A. auriculiformis and A. mangium respectively. The assemblies of A. auriculiformis and A. mangium had a total length of 21,022,649 bp and 17,838,260 bp, respectively, with the largest contig 15,262 bp long. We detected all ten monolignol biosynthetic genes using Blastx and further analysis revealed 18 lignin isoforms for each species. We also identified five contigs homologous to R2R3-MYB proteins in other plant species that are involved in transcriptional regulation of secondary cell wall formation and lignin deposition. We searched the contigs against public microRNA database and predicted the stem-loop structures of six highly conserved microRNA families (miR319, miR396, miR160, miR172, miR162 and miR168 and one legume-specific family (miR2086. Three microRNA target genes were predicted to be involved in wood formation and flavonoid biosynthesis. By using the assemblies as a reference, we discovered 16,648 and 9,335 high quality putative Single Nucleotide Polymorphisms (SNPs in the transcriptomes of A. auriculiformis and A. mangium

  17. 14C-labeled lignins as substrates for the study of lignin biodegradation and transformation

    International Nuclear Information System (INIS)

    Crawford, R.L.; Robinson, L.E.; Chen, A.M.

    1980-01-01

    Methods, both classical and isotopic, for quantifying lignin degradation are reviewed. Preparation and chemical characterization of 14 C-labeled lignins (both synthetic and plant-synthesized) are reviewed, with emphasis on the utilization of these 14 C-labeled substrates in biodegradation and biotransformation experiments. The scientific literature is reviewed concerning the use of 14 C-lignins to examine the following: microbial groups that are able to degrade lignins; lignin degradation in natural environments; biochemistry and microbial physiology of lignin degradation; biodegradability of industrial lignins and their by-products; and screening for industrially valuable, lignin-modifying microorganisms. Recent results obtained in our laboratory concerning lignin degradation by eubacteria are presented. Future directions for 14 C-methodology are examined

  18. Cytocompatible cellulose hydrogels containing trace lignin

    International Nuclear Information System (INIS)

    Nakasone, Kazuki; Kobayashi, Takaomi

    2016-01-01

    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 12 h. 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 0.43 N/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. - Highlights: • Cellulose hydrogel films with trace lignin were obtained from sugarcane bagasse. • Lignin content was found to be in the range of 1.62 − 0.68% by UV–Vis spectroscopy. • Higher lignin content strengthened mechanical properties of the hydrogel films. • Trace lignin affected the hydrogel morphology such as roughness and porosity. • High cell proliferation was observed in the hydrogel containing 1.68% lignin.

  19. Cytocompatible cellulose hydrogels containing trace lignin

    Energy Technology Data Exchange (ETDEWEB)

    Nakasone, Kazuki; Kobayashi, Takaomi, E-mail: takaomi@nagaoakut.ac.jp

    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 12 h. 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 0.43 N/mm{sup 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. - Highlights: • Cellulose hydrogel films with trace lignin were obtained from sugarcane bagasse. • Lignin content was found to be in the range of 1.62 − 0.68% by UV–Vis spectroscopy. • Higher lignin content strengthened mechanical properties of the hydrogel films. • Trace lignin affected the hydrogel morphology such as roughness and porosity. • High cell proliferation was observed in the hydrogel containing 1.68% lignin.

  20. Functional conservation of coenzyme Q biosynthetic genes among yeasts, plants, and humans.

    Directory of Open Access Journals (Sweden)

    Kazuhiro Hayashi

    Full Text Available Coenzyme Q (CoQ is an essential factor for aerobic growth and oxidative phosphorylation in the electron transport system. The biosynthetic pathway for CoQ has been proposed mainly from biochemical and genetic analyses of Escherichia coli and Saccharomyces cerevisiae; however, the biosynthetic pathway in higher eukaryotes has been explored in only a limited number of studies. We previously reported the roles of several genes involved in CoQ synthesis in the fission yeast Schizosaccharomyces pombe. Here, we expand these findings by identifying ten genes (dps1, dlp1, ppt1, and coq3-9 that are required for CoQ synthesis. CoQ10-deficient S. pombe coq deletion strains were generated and characterized. All mutant fission yeast strains were sensitive to oxidative stress, produced a large amount of sulfide, required an antioxidant to grow on minimal medium, and did not survive at the stationary phase. To compare the biosynthetic pathway of CoQ in fission yeast with that in higher eukaryotes, the ability of CoQ biosynthetic genes from humans and plants (Arabidopsis thaliana to functionally complement the S. pombe coq deletion strains was determined. With the exception of COQ9, expression of all other human and plant COQ genes recovered CoQ10 production by the fission yeast coq deletion strains, although the addition of a mitochondrial targeting sequence was required for human COQ3 and COQ7, as well as A. thaliana COQ6. In summary, this study describes the functional conservation of CoQ biosynthetic genes between yeasts, humans, and plants.

  1. Evidence supporting dissimilatory and assimilatory lignin degradation in Enterobacter lignolyticus SCF1

    Directory of Open Access Journals (Sweden)

    Kristen M DeAngelis

    2013-09-01

    Full Text Available The anaerobic isolate Enterobacter lignolyticus SCF1 was initially cultivated based on anaerobic growth on lignin as sole carbon source. The source of the isolated bacteria was from tropical forest soils that decompose litter rapidly with low and fluctuating redox potentials, making it likely that bacteria using oxygen-independent enzymes play an important role in decomposition. We have used transcriptomics and proteomics to examine the increased growth of the anaerobic isolate Enterobacter lignolyticus SCF1 when grown on media amended with lignin compared to unamended growth. Proteomics revealed accelerated xylose uptake and metabolism under lignin-amended growth, and lignin degradation via the 4-hydroxyphenylacetate degradation pathway, catalase/peroxidase enzymes, and the glutathione biosynthesis and glutathione S-transferase proteins. We also observed increased production of NADH-quinone oxidoreductase, other electron transport chain proteins, and ATP synthase and ATP-binding cassette (ABC transporters. We detected significant lignin degradation over time by absorbance, and also used metabolomics to demonstrate increased xylose utilization in lignin-amended compared to unamended growth. Our data shows the advantages of a multi-omics approach, where incomplete pathways identified by genomics were completed, and new observations made on coping with poor carbon availability. The fast growth, high efficiency and specificity of enzymes employed in bacterial anaerobic litter deconstruction makes these soils useful templates for improving biofuel production.

  2. Biobleaching chemistry of laccase-mediator systems on high-lignin-content kraft pulps

    International Nuclear Information System (INIS)

    Chakar, F.S.; Ragauskas, A.J.

    2004-01-01

    A high-lignin-content softwood kraft pulp was reacted with laccase in the presence of 1-hydroxybenzotriazole (HBT), N-acetyl-N-phenylhydroxylamine (NHA), and violuric acid (VA). The biodelignification response with violuric acid was superior to both 1-hydroxybenzotriazole and N-acetyl-N-phenylhydroxylamine. NMR analysis of residual lignins isolated before and after the biobleaching treatments revealed that the latter material was highly oxidized and that the magnitude of structural changes was most pronounced with the laccase - violuric acid biobleaching system. An increase in the content of carboxylic acid groups and a decrease in methoxyl groups were noted with all three laccase-mediator systems. The oxidation biobleaching pathway is directed primarily towards noncondensed C5 phenolic lignin functional structures for all three laccase-mediated systems. The laccase - violuric acid system was also reactive towards C5-condensed phenolic lignin structures. (author)

  3. Fabrication of environmentally biodegradable lignin nanoparticles.

    Science.gov (United States)

    Frangville, Camille; Rutkevičius, Marius; Richter, Alexander P; Velev, Orlin D; Stoyanov, Simeon D; Paunov, Vesselin N

    2012-12-21

    We developed a method for the fabrication of novel biodegradable nanoparticles (NPs) from lignin which are apparently non-toxic for microalgae and yeast. We compare two alternative methods for the synthesis of lignin NPs which result in particles of very different stability upon change of pH. The first method is based on precipitation of low-sulfonated lignin from an ethylene glycol solution by using diluted acidic aqueous solutions, which yields lignin NPs that are stable over a wide range of pH. The second approach is based on the acidic precipitation of lignin from a high-pH aqueous solution which produces NPs stable only at low pH. Our study reveals that lignin NPs from the ethylene glycol-based precipitation contain densely packed lignin domains which explain the stability of the NPs even at high pH. We characterised the properties of the produced lignin NPs and determined their loading capacities with hydrophilic actives. The results suggest that these NPs are highly porous and consist of smaller lignin domains. Tests with microalgae like Chlamydomonas reinhardtii and yeast incubated in lignin NP dispersions indicated that these NPs lack measurable effect on the viability of these microorganisms. Such biodegradable and environmentally compatible NPs can find applications as drug delivery vehicles, stabilisers of cosmetic and pharmaceutical formulations, or in other areas where they may replace more expensive and potentially toxic nanomaterials. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Evolution and Diversity of Biosynthetic Gene Clusters in Fusarium

    Directory of Open Access Journals (Sweden)

    Koen Hoogendoorn

    2018-06-01

    Full Text Available Plant pathogenic fungi in the Fusarium genus cause severe damage to crops, resulting in great financial losses and health hazards. Specialized metabolites synthesized by these fungi are known to play key roles in the infection process, and to provide survival advantages inside and outside the host. However, systematic studies of the evolution of specialized metabolite-coding potential across Fusarium have been scarce. Here, we apply a combination of bioinformatic approaches to identify biosynthetic gene clusters (BGCs across publicly available genomes from Fusarium, to group them into annotated families and to study gain/loss events of BGC families throughout the history of the genus. Comparison with MIBiG reference BGCs allowed assignment of 29 gene cluster families (GCFs to pathways responsible for the production of known compounds, while for 57 GCFs, the molecular products remain unknown. Comparative analysis of BGC repertoires using ancestral state reconstruction raised several new hypotheses on how BGCs contribute to Fusarium pathogenicity or host specificity, sometimes surprisingly so: for example, a gene cluster for the biosynthesis of hexadehydro-astechrome was identified in the genome of the biocontrol strain Fusarium oxysporum Fo47, while being absent in that of the tomato pathogen F. oxysporum f.sp. lycopersici. Several BGCs were also identified on supernumerary chromosomes; heterologous expression of genes for three terpene synthases encoded on the Fusarium poae supernumerary chromosome and subsequent GC/MS analysis showed that these genes are functional and encode enzymes that each are able to synthesize koraiol; this observed functional redundancy supports the hypothesis that localization of copies of BGCs on supernumerary chromosomes provides freedom for evolutionary innovations to occur, while the original function remains conserved. Altogether, this systematic overview of biosynthetic diversity in Fusarium paves the way for

  5. Knocking on wood: base metal complexes as catalysts for selective oxidation of lignin models and extracts.

    Science.gov (United States)

    Hanson, Susan K; Baker, R Tom

    2015-07-21

    This work began as part of a biomass conversion catalysis project with UC Santa Barbara funded by the first NSF Chemical Bonding Center, CATSB. Recognizing that catalytic aerobic oxidation of diol C-C bonds could potentially be used to break down lignocellulose, we began to synthesize oxovanadium complexes and explore their fundamental reactivity. Of course there were theories regarding the oxidation mechanism, but our mechanistic studies soon revealed a number of surprises of the type that keep all chemists coming back to the bench! We realized that these reactions were also exciting in that they actually used the oxygen-on-every-carbon property of biomass-derived molecules to control the selectivity of the oxidation. When we found that these oxovanadium complexes tended to convert sugars predominantly to formic acid and carbon dioxide, we replaced one of the OH groups with an ether and entered the dark world of lignin chemistry. In this Account, we summarize results from our collaboration and from our individual labs. In particular, we show that oxidation selectivity (C-C vs C-O bond cleavage) of lignin models using air and vanadium complexes depends on the ancillary ligands, the reaction solvent, and the substrate structure (i.e., phenolic vs non-phenolic). Selected vanadium complexes in the presence of added base serve as effective alcohol oxidation catalysts via a novel base-assisted dehydrogenation pathway. In contrast, copper catalysts effect direct C-C bond cleavage of these lignin models, presumably through a radical pathway. The most active vanadium catalyst exhibits unique activity for the depolymerization of organosolv lignin. After Weckhuysen's excellent 2010 review on lignin valorization, the number of catalysis studies and approaches on both lignin models and extracts has expanded rapidly. Today we are seeing new start-ups and lignin production facilities sprouting up across the globe as we all work to prove wrong the old pulp and paper chemist

  6. Differential expression of carotenoid biosynthetic pathway genes in ...

    Indian Academy of Sciences (India)

    2016-04-08

    Pandurangaiah S, Ravishankar KV, Shivashankar KS, Sadashiva AT, Pillakenchappa K and Narayanan SK ... development and validation of LCY-B and CYC-B in selected contrasting F2 plants (red ripe fruits) derived from the cross.

  7. Composition of acylglycerols in castor oil and their biosynthetic pathway

    Science.gov (United States)

    Castor oil has many industrial uses, such as the manufacture of aviation lubricant, plastics, paints, coatings, and cosmetics, because of its high content of ricinoleate (hydroxy fatty acid). We have identified many molecular species of acylglycerols using electrospray ionization mass spectrometry o...

  8. Conformational analysis of lignin models

    International Nuclear Information System (INIS)

    Santos, Helio F. dos

    2001-01-01

    The conformational equilibrium for two 5,5' biphenyl lignin models have been analyzed using a quantum mechanical semiempirical method. The gas phase and solution structures are discussed based on the NMR and X-ray experimental data. The results obtained showed that the observed conformations are solvent-dependent, being the geometries and the thermodynamic properties correlated with the experimental information. This study shows how a systematic theoretical conformational analysis can help to understand chemical processes at a molecular level. (author)

  9. Lignin-Retaining Transparent Wood.

    Science.gov (United States)

    Li, Yuanyuan; Fu, Qiliang; Rojas, Ramiro; Yan, Min; Lawoko, Martin; Berglund, Lars

    2017-09-11

    Optically transparent wood, combining optical and mechanical performance, is an emerging new material for light-transmitting structures in buildings with the aim of reducing energy consumption. One of the main obstacles for transparent wood fabrication is delignification, where around 30 wt % of wood tissue is removed to reduce light absorption and refractive index mismatch. This step is time consuming and not environmentally benign. Moreover, lignin removal weakens the wood structure, limiting the fabrication of large structures. A green and industrially feasible method has now been developed to prepare transparent wood. Up to 80 wt % of lignin is preserved, leading to a stronger wood template compared to the delignified alternative. After polymer infiltration, a high-lignin-content transparent wood with transmittance of 83 %, haze of 75 %, thermal conductivity of 0.23 W mK -1 , and work-tofracture of 1.2 MJ m -3 (a magnitude higher than glass) was obtained. This transparent wood preparation method is efficient and applicable to various wood species. The transparent wood obtained shows potential for application in energy-saving buildings. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  10. Ferricyanide-based analysis of aqueous lignin suspension revealed sequestration of water-soluble lignin moieties

    OpenAIRE

    Joshua, CJ; Simmons, BA; Singer, SW

    2016-01-01

    © 2016 The Royal Society of Chemistry. This study describes the application of a ferricyanide-based assay as a simple and inexpensive assay for rapid analysis of aqueous lignin samples. The assay measures the formation of Prussian blue from the redox reaction between a mixture of potassium ferricyanide and ferric chloride, and phenolic hydroxyl groups of lignin or lignin-derived phenolic moieties. This study revealed that soluble lignin moieties exhibited stronger ferricyanide reactivity than...

  11. Environmental economics of lignin derived transport fuels

    OpenAIRE

    Obydenkova, SV; Kouris, P Panagiotis; Hensen, EJM Emiel; Heeres, Hero J; Boot, MD Michael

    2017-01-01

    This paper explores the environmental and economic aspects of fast pyrolytic conversion of lignin, obtained from 2G ethanol plants, to transport fuels for both the marine and automotive markets. Various scenarios are explored, pertaining to aggregation of lignin from several sites, alternative energy carries to replace lignin, transport modalities, and allocation methodology. The results highlight two critical factors that ultimately determine the economic and/or environmental fuel viability....

  12. Radical nature of C- lignin

    Science.gov (United States)

    Laura Berstis; Thomas Elder; Michael Crowley; Gregg T. Beckham

    2016-01-01

    The recently discovered lignin composed of caffeoyl alcohol monolignols or C-lignin is particularly intriguing given its homogeneous, linear polymeric structure and exclusive benzodioxane linkage between monomers. By virtue of this simplified chemistry, the potential emerges for improved valorization strategies with C-lignin relative to other natural heterogeneous...

  13. Recovering hydrocarbons with surfactants from lignin

    Energy Technology Data Exchange (ETDEWEB)

    Naae, D.G.; Whittington, L.E.; Ledoux, W.A.; Debons, F.E.

    1988-11-29

    This patent describes a method of recovering hydrocarbons from an underground hydrocarbon formation penetrated by at least one injection well and at least one production well, which comprises: injecting into the formation through an injection well a surfactant slug comprising about 0.1% to about 10% by weight of surfactants produced from lignin, the surfactants produced by placing lignin in contact with water, converting the lignin into low molecular weight lignin phenols by reducing the lignin in the presence of a reducing agent of carbon monoxide or hydrogen creating a reduction reaction mixture comprising oil soluble lignin phenols, the reduction occurring at a temperature greater than about 200/sup 0/C and a pressure greater than about 100 psi, recovering the oil soluble lignin phenols from the reduction mixture, and converting the lignin phenols into lignin surfactants by a reaction selected from the group consisting of alkoxylation, sulfonation, sulfation, aklylation, sulfomethylation, and alkoxysulfation; injecting into the formation through the injection well a drive fluid to push the surfactant slug towards a production well; and recovering hydrocarbons at the production well.

  14. Biological and Catalytic Conversion of Sugars and Lignin Publications |

    Science.gov (United States)

    biorefinery lignins, ACS Sust. Chem. Eng. Lignin depolymerization with nitrate-intercalated hydrotalcite catalysts, ACS Catalysis Pyrolysis reaction networks for lignin model compounds: Unraveling thermal Free Energy, J. Amer. Chem. Soc. Process Design and Economics for the Conversion of Lignocellulosic

  15. Characterization of the biosynthetic gene cluster for cryptic phthoxazolin A in Streptomyces avermitilis.

    Directory of Open Access Journals (Sweden)

    Dian Anggraini Suroto

    Full Text Available Phthoxazolin A, an oxazole-containing polyketide, has a broad spectrum of anti-oomycete activity and herbicidal activity. We recently identified phthoxazolin A as a cryptic metabolite of Streptomyces avermitilis that produces the important anthelmintic agent avermectin. Even though genome data of S. avermitilis is publicly available, no plausible biosynthetic gene cluster for phthoxazolin A is apparent in the sequence data. Here, we identified and characterized the phthoxazolin A (ptx biosynthetic gene cluster through genome sequencing, comparative genomic analysis, and gene disruption. Sequence analysis uncovered that the putative ptx biosynthetic genes are laid on an extra genomic region that is not found in the public database, and 8 open reading frames in the extra genomic region could be assigned roles in the biosynthesis of the oxazole ring, triene polyketide and carbamoyl moieties. Disruption of the ptxA gene encoding a discrete acyltransferase resulted in a complete loss of phthoxazolin A production, confirming that the trans-AT type I PKS system is responsible for the phthoxazolin A biosynthesis. Based on the predicted functional domains in the ptx assembly line, we propose the biosynthetic pathway of phthoxazolin A.

  16. Studies on Lignin-Based Adhesives for Particleboard Panels

    OpenAIRE

    ÇETİN, Nihat Sami; ÖZMEN, Nilgül

    2003-01-01

    The ultimate aim of this work was to develop a phenolic resin for partially replacing phenol with modified organosolv lignin in phenol-formaldehyde (PF) resin production. The lignin-formaldehyde relationship was determined in a reactivity test. Organosolv lignin-phenol-formaldehyde (LPF) resins were produced in a two-step preparation with different additions of lignin. The method selected for the manufacture of lignin resins dealt with modification of the lignin by the methylolation route. Th...

  17. Multiplex PCR analysis of fumonisin biosynthetic genes in fumonisin-nonproducing Aspergillus niger and A. awamori strains

    Science.gov (United States)

    In order to determine the genetic basis for loss of fumonisin B¬2 (FB2) biosynthesis in FB2 non-producing A. niger strains, we developed multiplex PCR primer sets to amplify fragments of eight fumonisin biosynthetic pathway (fum) genes. Fragments of all eight fum genes were amplified in FB2-produci...

  18. Metabolic profiling of alternative NAD biosynthetic routes in mouse tissues.

    Directory of Open Access Journals (Sweden)

    Valerio Mori

    Full Text Available NAD plays essential redox and non-redox roles in cell biology. In mammals, its de novo and recycling biosynthetic pathways encompass two independent branches, the "amidated" and "deamidated" routes. Here we focused on the indispensable enzymes gating these two routes, i.e. nicotinamide mononucleotide adenylyltransferase (NMNAT, which in mammals comprises three distinct isozymes, and NAD synthetase (NADS. First, we measured the in vitro activity of the enzymes, and the levels of all their substrates and products in a number of tissues from the C57BL/6 mouse. Second, from these data, we derived in vivo estimates of enzymes'rates and quantitative contributions to NAD homeostasis. The NMNAT activity, mainly represented by nuclear NMNAT1, appears to be high and nonrate-limiting in all examined tissues, except in blood. The NADS activity, however, appears rate-limiting in lung and skeletal muscle, where its undetectable levels parallel a relative accumulation of the enzyme's substrate NaAD (nicotinic acid adenine dinucleotide. In all tissues, the amidated NAD route was predominant, displaying highest rates in liver and kidney, and lowest in blood. In contrast, the minor deamidated route showed higher relative proportions in blood and small intestine, and higher absolute values in liver and small intestine. Such results provide the first comprehensive picture of the balance of the two alternative NAD biosynthetic routes in different mammalian tissues under physiological conditions. This fills a gap in the current knowledge of NAD biosynthesis, and provides a crucial information for the study of NAD metabolism and its role in disease.

  19. Emergent biosynthetic capacity in simple microbial communities.

    Directory of Open Access Journals (Sweden)

    Hsuan-Chao Chiu

    2014-07-01

    Full Text Available Microbes have an astonishing capacity to transform their environments. Yet, the metabolic capacity of a single species is limited and the vast majority of microorganisms form complex communities and join forces to exhibit capabilities far exceeding those achieved by any single species. Such enhanced metabolic capacities represent a promising route to many medical, environmental, and industrial applications and call for the development of a predictive, systems-level understanding of synergistic microbial capacity. Here we present a comprehensive computational framework, integrating high-quality metabolic models of multiple species, temporal dynamics, and flux variability analysis, to study the metabolic capacity and dynamics of simple two-species microbial ecosystems. We specifically focus on detecting emergent biosynthetic capacity--instances in which a community growing on some medium produces and secretes metabolites that are not secreted by any member species when growing in isolation on that same medium. Using this framework to model a large collection of two-species communities on multiple media, we demonstrate that emergent biosynthetic capacity is highly prevalent. We identify commonly observed emergent metabolites and metabolic reprogramming patterns, characterizing typical mechanisms of emergent capacity. We further find that emergent secretion tends to occur in two waves, the first as soon as the two organisms are introduced, and the second when the medium is depleted and nutrients become limited. Finally, aiming to identify global community determinants of emergent capacity, we find a marked association between the level of emergent biosynthetic capacity and the functional/phylogenetic distance between community members. Specifically, we demonstrate a "Goldilocks" principle, where high levels of emergent capacity are observed when the species comprising the community are functionally neither too close, nor too distant. Taken together

  20. Fabrication of Environmentally Biodegradable Lignin Nanoparticles

    NARCIS (Netherlands)

    Frangville, C.; Rutkevicius, M.; Richter, A.P.; Velev, O.D.; Stoyanov, S.D.; Paunov, V.N.

    2012-01-01

    We developed a method for the fabrication of novel biodegradable nanoparticles (NPs) from lignin which are apparently non-toxic for microalgae and yeast. We compare two alternative methods for the synthesis of lignin NPs which result in particles of very different stability upon change of pH. The

  1. Environmental economics of lignin derived transport fuels

    NARCIS (Netherlands)

    Obydenkova, Svetlana V.; Kouris, Panos D.; Hensen, Emiel J. M.; Heeres, Hero J.; Boot, Michael D.

    2017-01-01

    This paper explores the environmental and economic aspects of fast pyrolytic conversion of lignin, obtained from 2G ethanol plants, to transport fuels for both the marine and automotive markets. Various scenarios are explored, pertaining to aggregation of lignin from several sites, alternative

  2. Bacterial enzymes involved in lignin degradation

    NARCIS (Netherlands)

    de Gonzalo, Gonzalo; Colpa, Dana I; Habib, Mohamed H M; Fraaije, Marco W

    2016-01-01

    Lignin forms a large part of plant biomass. It is a highly heterogeneous polymer of 4-hydroxyphenylpropanoid units and is embedded within polysaccharide polymers forming lignocellulose. Lignin provides strength and rigidity to plants and is rather resilient towards degradation. To improve the

  3. Lignin Biodegradation with Laccase-Mediator Systems

    International Nuclear Information System (INIS)

    Christopher, Lew Paul; Yao, Bin; Ji, Yun

    2014-01-01

    Lignin has a significant and largely unrealized potential as a source for the sustainable production of fuels and bulk high-value chemicals. It can replace fossil-based oil as a renewable feedstock that would bring about socio-economic and environmental benefits in our transition to a biobased economy. The efficient utilization of lignin however requires its depolymerization to low-molecular weight phenolics and aromatics that can then serve as the building blocks for chemical syntheses of high-value products. The ability of laccase to attack and degrade lignin in conjunction with laccase mediators is currently viewed as one of the potential “breakthrough” applications for lignin valorization. Here, we review the recent progress in lignin biodegradation with laccase-mediator systems, and research needs that need to be addressed in this field.

  4. Lignin Biodegradation with Laccase-Mediator Systems

    Energy Technology Data Exchange (ETDEWEB)

    Christopher, Lew Paul, E-mail: lew.christopher@sdsmt.edu [Center for Bioprocessing Research and Development, South Dakota School of Mines & Technology, Rapid City, SD (United States); Department of Civil and Environmental Engineering, South Dakota School of Mines & Technology, Rapid City, SD (United States); Yao, Bin [Center for Bioprocessing Research and Development, South Dakota School of Mines & Technology, Rapid City, SD (United States); Ji, Yun [Department of Chemical Engineering, University of North Dakota, Grand Forks, ND (United States)

    2014-03-31

    Lignin has a significant and largely unrealized potential as a source for the sustainable production of fuels and bulk high-value chemicals. It can replace fossil-based oil as a renewable feedstock that would bring about socio-economic and environmental benefits in our transition to a biobased economy. The efficient utilization of lignin however requires its depolymerization to low-molecular weight phenolics and aromatics that can then serve as the building blocks for chemical syntheses of high-value products. The ability of laccase to attack and degrade lignin in conjunction with laccase mediators is currently viewed as one of the potential “breakthrough” applications for lignin valorization. Here, we review the recent progress in lignin biodegradation with laccase-mediator systems, and research needs that need to be addressed in this field.

  5. Flg22-Triggered Immunity Negatively Regulates Key BR Biosynthetic Genes.

    Science.gov (United States)

    Jiménez-Góngora, Tamara; Kim, Seong-Ki; Lozano-Durán, Rosa; Zipfel, Cyril

    2015-01-01

    In plants, activation of growth and activation of immunity are opposing processes that define a trade-off. In the past few years, the growth-promoting hormones brassinosteroids (BR) have emerged as negative regulators of pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI), promoting growth at the expense of defense. The crosstalk between BR and PTI signaling was described as negative and unidirectional, since activation of PTI does not affect several analyzed steps in the BR signaling pathway. In this work, we describe that activation of PTI by the bacterial PAMP flg22 results in the reduced expression of BR biosynthetic genes. This effect does not require BR perception or signaling, and occurs within 15 min of flg22 treatment. Since the described PTI-induced repression of gene expression may result in a reduction in BR biosynthesis, the crosstalk between PTI and BR could actually be negative and bidirectional, a possibility that should be taken into account when considering the interaction between these two pathways.

  6. Extending the biosynthetic repertoires of cyanobacteria and chloroplasts.

    Science.gov (United States)

    Nielsen, Agnieszka Zygadlo; Mellor, Silas Busck; Vavitsas, Konstantinos; Wlodarczyk, Artur Jacek; Gnanasekaran, Thiyagarajan; Perestrello Ramos H de Jesus, Maria; King, Brian Christopher; Bakowski, Kamil; Jensen, Poul Erik

    2016-07-01

    Chloroplasts in plants and algae and photosynthetic microorganisms such as cyanobacteria are emerging hosts for sustainable production of valuable biochemicals, using only inorganic nutrients, water, CO2 and light as inputs. In the past decade, many bioengineering efforts have focused on metabolic engineering and synthetic biology in the chloroplast or in cyanobacteria for the production of fuels, chemicals and complex, high-value bioactive molecules. Biosynthesis of all these compounds can be performed in photosynthetic organelles/organisms by heterologous expression of the appropriate pathways, but this requires optimization of carbon flux and reducing power, and a thorough understanding of regulatory pathways. Secretion or storage of the compounds produced can be exploited for the isolation or confinement of the desired compounds. In this review, we explore the use of chloroplasts and cyanobacteria as biosynthetic compartments and hosts, and we estimate the levels of production to be expected from photosynthetic hosts in light of the fraction of electrons and carbon that can potentially be diverted from photosynthesis. The supply of reducing power, in the form of electrons derived from the photosynthetic light reactions, appears to be non-limiting, but redirection of the fixed carbon via precursor molecules presents a challenge. We also discuss the available synthetic biology tools and the need to expand the molecular toolbox to facilitate cellular reprogramming for increased production yields in both cyanobacteria and chloroplasts. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

  7. Characterization of novel Brown midrib 6 mutations affecting lignin biosynthesis in sorghum

    Science.gov (United States)

    The presence of lignin reduces the quality of lignocellulosic biomass for forage materials and feedstock for biofuels. In C4 grasses, the brown midrib phenotype has been linked to mutations to genes in the monolignol biosynthesis pathway. For example, the Bmr6 gene in sorghum (Sorghum bicolor) has b...

  8. Fractionation of hemicelluloses and lignin from rice straw by combining autohydrolysis and optimised mild organosolv delignification

    NARCIS (Netherlands)

    Moniz, Patrícia; Lino, João; Duarte, Luís C.; Roseiro, Luísa B.; Boeriu, Carmen G.; Pereira, Helena; Carvalheiro, Florbela

    2015-01-01

    An integrated strategy was followed to valorise rice straw, one of the most relevant biomass feedstocks available worldwide, to selectively recover solubilised hemicelluloses and lignin. The pathway encompassed the use of autohydrolysis to hydrolyse the hemicelluloses and an ethanol-based

  9. A genomics based discovery of secondary metabolite biosynthetic gene clusters in Aspergillus ustus.

    Directory of Open Access Journals (Sweden)

    Borui Pi

    Full Text Available Secondary metabolites (SMs produced by Aspergillus have been extensively studied for their crucial roles in human health, medicine and industrial production. However, the resulting information is almost exclusively derived from a few model organisms, including A. nidulans and A. fumigatus, but little is known about rare pathogens. In this study, we performed a genomics based discovery of SM biosynthetic gene clusters in Aspergillus ustus, a rare human pathogen. A total of 52 gene clusters were identified in the draft genome of A. ustus 3.3904, such as the sterigmatocystin biosynthesis pathway that was commonly found in Aspergillus species. In addition, several SM biosynthetic gene clusters were firstly identified in Aspergillus that were possibly acquired by horizontal gene transfer, including the vrt cluster that is responsible for viridicatumtoxin production. Comparative genomics revealed that A. ustus shared the largest number of SM biosynthetic gene clusters with A. nidulans, but much fewer with other Aspergilli like A. niger and A. oryzae. These findings would help to understand the diversity and evolution of SM biosynthesis pathways in genus Aspergillus, and we hope they will also promote the development of fungal identification methodology in clinic.

  10. A Genomics Based Discovery of Secondary Metabolite Biosynthetic Gene Clusters in Aspergillus ustus

    Science.gov (United States)

    Pi, Borui; Yu, Dongliang; Dai, Fangwei; Song, Xiaoming; Zhu, Congyi; Li, Hongye; Yu, Yunsong

    2015-01-01

    Secondary metabolites (SMs) produced by Aspergillus have been extensively studied for their crucial roles in human health, medicine and industrial production. However, the resulting information is almost exclusively derived from a few model organisms, including A. nidulans and A. fumigatus, but little is known about rare pathogens. In this study, we performed a genomics based discovery of SM biosynthetic gene clusters in Aspergillus ustus, a rare human pathogen. A total of 52 gene clusters were identified in the draft genome of A. ustus 3.3904, such as the sterigmatocystin biosynthesis pathway that was commonly found in Aspergillus species. In addition, several SM biosynthetic gene clusters were firstly identified in Aspergillus that were possibly acquired by horizontal gene transfer, including the vrt cluster that is responsible for viridicatumtoxin production. Comparative genomics revealed that A. ustus shared the largest number of SM biosynthetic gene clusters with A. nidulans, but much fewer with other Aspergilli like A. niger and A. oryzae. These findings would help to understand the diversity and evolution of SM biosynthesis pathways in genus Aspergillus, and we hope they will also promote the development of fungal identification methodology in clinic. PMID:25706180

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Toward engineering E. coli with an autoregulatory system for lignin valorization.

    Science.gov (United States)

    Wu, Weihua; Liu, Fang; Singh, Seema

    2018-03-20

    Efficient lignin valorization could add more than 10-fold the value gained from burning it for energy and is critical for economic viability of future biorefineries. However, lignin-derived aromatics from biomass pretreatment are known to be potent fermentation inhibitors in microbial production of fuels and other value-added chemicals. In addition, isopropyl-β-d-1-thiogalactopyranoside and other inducers are routinely added into fermentation broth to induce the expression of pathway enzymes, which further adds to the overall process cost. An autoregulatory system that can diminish the aromatics' toxicity as well as be substrate-inducible can be the key for successful integration of lignin valorization into future lignocellulosic biorefineries. Toward that goal, in this study an autoregulatory system is demonstrated that alleviates the toxicity issue and eliminates the cost of an external inducer. Specifically, this system is composed of a catechol biosynthesis pathway coexpressed with an active aromatic transporter CouP under induction by a vanillin self-inducible promoter, ADH7, to effectively convert the lignin-derived aromatics into value-added chemicals using Escherichia coli as a host. The constructed autoregulatory system can efficiently transport vanillin across the cell membrane and convert it to catechol. Compared with the system without CouP expression, the expression of catechol biosynthesis pathway with transporter CouP significantly improved the catechol yields about 30% and 40% under promoter pTrc and ADH7, respectively. This study demonstrated an aromatic-induced autoregulatory system that enabled conversion of lignin-derived aromatics into catechol without the addition of any costly, external inducers, providing a promising and economically viable route for lignin valorization. Copyright © 2018 the Author(s). Published by PNAS.

  13. Lignin solubilisation and gentle fractionation in liquid ammonia

    NARCIS (Netherlands)

    Strassberger, Z.; Prinsen, P.; Klis, van der F.; Es, van D.S.; Tanase, S.; Rothenberg, G.

    2015-01-01

    We present a simple method for solubilising lignin using liquid ammonia. Unlike water, which requires harsh conditions, ammonia can solubilise technical lignins, in particular kraft lignin. A commercial pine wood Kraft lignin (Indulin AT) was solubilized instantaneously at room temperature and 7–11

  14. The Use of Esterified Lignin for Synthesis of Durable Composites

    Science.gov (United States)

    S. Olsson; E. Ostmark; R.E. Ibach; C.M. Clemons; K.B. Segerholm; F. Englund

    2011-01-01

    Lignin is a natural polymer and one of the most abundant materials on earth. Despite this fact, lignin is often viewed as a by-product in chemical pulp processing and the use of lignin as a sustainable material is low. However, research and public awareness of sustainability have opened up new possibilities for using lignin as a material.

  15. Animal bioavailability of defined xenobiotic lignin metabolites

    International Nuclear Information System (INIS)

    Sandermann, H. Jr.; Arjmand, M.; Gennity, I.; Winkler, R.; Struble, C.B.; Aschbacher, P.W.

    1990-01-01

    Lignin has been recognized as a major component of bound pesticide residues in plants and is thought to be undigestible in animals. Two defined ring-U- 14 C-labeled chloroaniline/lignin metabolites have now been fed to rats, where a release of ∼66% of the bound xenobiotic occurred in the form of simple chloroaniline derivatives. The observed high degree of bioavailability indicates that bound pesticidal residues may possess ecotoxicological significance. In parallel studies, the white-rot fungus Phanerochaete chrysosporium was more efficient, and a soil system was much less efficient, in the degradation of the [ring-U- 14 C]chloroaniline/lignin metabolites

  16. Can laccases catalyze bond cleavage in lignin?

    DEFF Research Database (Denmark)

    Munk, Line; Sitarz, Anna Katarzyna; Kalyani, Dayanand

    2015-01-01

    illustrations of the putative laccase catalyzed reactions, including the possible reactions of the reactive radical intermediates taking place after the initial oxidation of the phenol-hydroxyl groups, we show that i) Laccase activity is able to catalyze bond cleavage in low molecular weight phenolic lignin......-substituted phenols, benzenethiols, polyphenols, and polyamines, which may be oxidized. In addition, the currently available analytical methods that can be used to detect enzyme catalyzed changes in lignin are summarized, and an improved nomenclature for unequivocal interpretation of the action of laccases on lignin...

  17. The synthesis and analysis of lignin-bound Hibbert ketone structures in technical lignins.

    Science.gov (United States)

    Miles-Barrett, Daniel M; Neal, Andrew R; Hand, Calum; Montgomery, James R D; Panovic, Isabella; Ojo, O Stephen; Lancefield, Christopher S; Cordes, David B; Slawin, Alexandra M Z; Lebl, Tomas; Westwood, Nicholas J

    2016-10-25

    Understanding the structure of technical lignins resulting from acid-catalysed treatment of lignocellulosic biomass is important for their future applications. Here we report an investigation into the fate of lignin under acidic aqueous organosolv conditions. In particular we examine in detail the formation and reactivity of non-native Hibbert ketone structures found in isolated organosolv lignins from both Douglas fir and beech woods. Through the use of model compounds combined with HSQC, HMBC and HSQC-TOCSY NMR experiments we demonstrate that, depending on the lignin source, both S and G lignin-bound Hibbert ketone units can be present. We also show that these units can serve as a source of novel mono-aromatic compounds following an additional lignin depolymerisation reaction.

  18. Survey of Lignin-Structure Changes and Depolymerization during Ionic Liquid Pretreatment

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Tanmoy; Isern, Nancy G.; Sun, Jian; Wang, Eileen; Hull, Sarah; Cort, John R.; Simmons, Blake A.; Singh, Seema

    2017-09-26

    A detailed study of chemical changes in lignin structure during the ionic liquid (IL) pretreatment process is not only pivotal for understanding and overcoming biomass recalcitrance during IL pretreatment, but also is necessary for designing new routes for lignin valorization. Chemical changes in lignin were systematically studied as a function of pretreatment temperature, time and type of IL used. Kraft lignin was used as the lignin source and common pretreatment conditions were employed using three different ILs of varying chemical structure in terms of acidic or basic character. The chemical changes in the lignin structure due to IL pretreatment processes were monitored using 1H-13C HSQC NMR, 31P NMR, elemental analysis, GPC, FT-IR, and the depolymerized products were analyzed using GC-MS. Although pretreatment in acidic IL, triethylammonium hydrogensulfate ([TEA][HSO4]) results in maximum decrease in β-aryl ether bond, maximum dehydration and recondensation pathways were also evident, with the net process showing a minimum decrease in the molecular weight of regenerated lignin. However, 1-ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]) pretreatment yields a smaller decrease in the β-aryl ether content along with minimum evidence of recondensation, resulting in the maximum decrease in the molecular weight. Cholinium lysinate ([Ch][Lys]) pretreatment shows an intermediate result, with moderate depolymerization, dehydration and recondensation observed. The depolymerization products after IL pretreatment are found to be a function of the pretreatment temperature and the specific chemical nature of the IL used. At higher pretreatment temperature, [Ch][Lys] pretreatment yields guaiacol, [TEA][HSO4] yields guaiacylacetone, and [C2C1Im][OAc] yields both guaiacol and guaiacylacetone as major products. These results clearly indicate that the changes in lignin structure as well as the depolymerized product profile depend on the pretreatment conditions and the nature

  19. Characterization of the effects of lignin and lignin complex particles as filler on a polystyrene film

    Energy Technology Data Exchange (ETDEWEB)

    El-Zawawy, Waleed K., E-mail: wkzawawy@yahoo.com [Cellulose and Paper Department, National Research Center, El-Tahrir St., Giza (Egypt); Ibrahim, Maha M. [Cellulose and Paper Department, National Research Center, El-Tahrir St., Giza (Egypt); Belgacem, Mohamed Naceur; Dufresne, Alain [Grenoble Institute of Technology (INP) - The International School of Paper, Print Media and Biomaterials (PAGORA), BP 65, 38402 Saint Martin d' Heres cedex, Grenoble (France)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer We have studied the use of Co(II) to form a complex with the lignin. We use first vanillin as the lignin model and we observed a change in color for the produced complex depending on the light wavelength. The use of other transition metals does not give the same observation. Black-Right-Pointing-Pointer The use of the transition metal with the lignin precipitated from the black liquor after pulping of agricultural residues, gave a fluorescent color under fluorescent microscope. Black-Right-Pointing-Pointer We applied the resulted lignin complex to prepare polymer film that can be used as special polymer packaging which can be color changed under different wavelengths. - Abstract: The work in this research outlines the use of lignin precipitated from lignocellulosic substrate as fillers after modified with transition metal cations, Fe(III), Ni(II) and Co(II), in the production of a polystyrene based composite for polymer packaging applications. Virgin polystyrene was compared with lignin and lignin complex filled composites with loading of 5% by weight prepared using twin screw extrusion. The lignin complexes were first characterized by the UV spectra to identify the new absorption bands occurred due to the complex formation. Moreover, lignin model, namely vanillin, was used to notify the geometric structure of the resulting complexes applying the GC mass spectra. Scanning electron microscopy was used to indicate the change in the morphological structure of the filler particles. On the other hand, the mechanical and thermal analysis for the resulting polymer composites was studied and it was noticed that the type of lignin or lignin complex plays a roll in the results. The inclusion of the Co(II)-lignin complex was observed to increase the tensile strength of the resulting polymer composite and a decrease of the glass transition temperature. Furthermore, light wave lengths and UV fluorescent microscope were used to identify

  20. Characterization of the effects of lignin and lignin complex particles as filler on a polystyrene film

    International Nuclear Information System (INIS)

    El-Zawawy, Waleed K.; Ibrahim, Maha M.; Belgacem, Mohamed Naceur; Dufresne, Alain

    2011-01-01

    Highlights: ► We have studied the use of Co(II) to form a complex with the lignin. We use first vanillin as the lignin model and we observed a change in color for the produced complex depending on the light wavelength. The use of other transition metals does not give the same observation. ► The use of the transition metal with the lignin precipitated from the black liquor after pulping of agricultural residues, gave a fluorescent color under fluorescent microscope. ► We applied the resulted lignin complex to prepare polymer film that can be used as special polymer packaging which can be color changed under different wavelengths. - Abstract: The work in this research outlines the use of lignin precipitated from lignocellulosic substrate as fillers after modified with transition metal cations, Fe(III), Ni(II) and Co(II), in the production of a polystyrene based composite for polymer packaging applications. Virgin polystyrene was compared with lignin and lignin complex filled composites with loading of 5% by weight prepared using twin screw extrusion. The lignin complexes were first characterized by the UV spectra to identify the new absorption bands occurred due to the complex formation. Moreover, lignin model, namely vanillin, was used to notify the geometric structure of the resulting complexes applying the GC mass spectra. Scanning electron microscopy was used to indicate the change in the morphological structure of the filler particles. On the other hand, the mechanical and thermal analysis for the resulting polymer composites was studied and it was noticed that the type of lignin or lignin complex plays a roll in the results. The inclusion of the Co(II)–lignin complex was observed to increase the tensile strength of the resulting polymer composite and a decrease of the glass transition temperature. Furthermore, light wave lengths and UV fluorescent microscope were used to identify the change of color for the resulting polymer film.

  1. Molecular evidence for lignin degradation in sulfate-reducing mangrove sediments (Amazônia, Brazil)

    Science.gov (United States)

    Dittmar, Thorsten; Lara, Rubén José

    2001-05-01

    - Molecular lignin analyses have become a powerful quantitative approach for estimating flux and fate of vascular plant organic matter in coastal and marine environments. The use of a specific molecular biomarker requires detailed knowledge of its decomposition rates relative to the associated organic matter and its structural diagenetic changes. To gain insight into the poorly known processes of anaerobic lignin diagenesis, molecular analyses were performed in the sulfate-reducing sediment of a north Brazilian mangrove. Organic matter in samples representing different diagenetic stages (i.e., fresh litter, a sediment core, and percolating water) was characterized by alkaline CuO oxidation for lignin composition, element (C, N), and stable carbon isotope analyses. On the basis of these results and on a balance model, long-term in situ decomposition rates of lignin in sulfate-reducing sediments were estimated for the first time. The half-life ( T1/2) of lignin derived from mangrove leaf litter (mainly Rhizophora mangle) was ˜150 yr in the upper 1.5 m of the sediment. Associated organic carbon from leaf tissue was depleted to ˜75% within weeks, followed by a slow mineralization in the sediment ( T1/2 ≈ 300 yr). Unlike the known pathways of lignin diagenesis, even highly degraded lignin did not show any alterations of the propyl or methoxyl side chains, as evident from stable acid to aldehyde ratios and the proportion of methoxylated phenols (vanillyl and syringyl phenols). Aromatic ring cleavage is probably the principal mechanism for lignin decay in the studied environment. Cinnamyl phenols were highly abundant in mangrove leaves and were rapidly depleted during early diagenesis. Thus, the cinnamyl to vanillyl ratio could be used as a tracer for early diagenesis even under the sulfate-reducing conditions. Syringyl phenols were removed from dissolved organic matter in interstitial water, probably by sorption onto the sediment. Suspended organic matter in a

  2. Lignine als grondstof voor asfalt en dakbedekking

    NARCIS (Netherlands)

    Vliet, D. van

    2014-01-01

    Zet een chemicus en een wegenbouwer bij elkoor en je kunt het onverwachte verwachten. Somen brouwden dr. Ted Sloghek en ing. Dave van Vliet van TNO een type bitumen met verbeterde eigenschoppen. Het basismateriaal: lignine

  3. Lignin biomass conversion into chemicals and fuels

    DEFF Research Database (Denmark)

    Melián Rodríguez, Mayra

    Second-generation biomass or lignocellulosic biomass, which is mainly composed of cellulose, hemicellulose and lignin, is a very important and promising feedstock for the renewable production of fuels and chemicals of the future. Lignin is the second most abundant natural polymer, representing 30...... and show similar, although simplified, characteristics to the natural biopolymer. Among them, the most abundant structural unit is the β-O-4, representing approximately 60% of the bonds in hardwood and 45-50% of those in softwood. Oxidative depolymerization is one of the most viable methods for lignin...... valorization. It involves the cleavage of ether bonds, such as β-O-4 and other linkages present in lignin and its model compounds, giving aldehydes or carboxylic acids as products, depending on the reaction conditions used. In Chapter 2 of this thesis, the preparation, characterization and catalytic...

  4. Composition comprising lignin and antidi arrheal component

    DEFF Research Database (Denmark)

    2008-01-01

    The present invention relates to a composition comprising lignin and at least one compound selected from the group consisting of bromelain, papain, tannin, carvacrol, thymol, alliin, allicin, fenugreek seed, egg, poppy, poppy seeds, humic acid, roots, kaolin, catechu, cellulase, flavonoid...

  5. Isolation and Physicochemical Characterization of Lignin from ...

    African Journals Online (AJOL)

    Muzakir

    and properties, lignin offers a perspective for higher value-added ... priority for the development and implementation of the lignocellulosic ... of about 2.5 m and adaptable to most soils. It had ..... in young versus adult Eucalyptus globulus plants.

  6. Elucidating the biosynthetic and regulatory mechanisms of flavonoid-derived bioactive components in Epimedium sagittatum

    Directory of Open Access Journals (Sweden)

    Wenjun eHuang

    2015-09-01

    Full Text Available Herba epimedii (Epimedium, a traditional Chinese medicine, has been widely used as a kidney tonic and antirheumatic medicine for thousands of years. In Epimedium, flavonoids have been demonstrated to be the main bioactive components (BCs. However, the molecular biosynthetic and regulatory mechanisms of flavonoid-derived BCs remain obscure. In this study, we isolated twelve structural genes and two putative transcription factors (TFs in the flavonoid pathway. Phytochemical analysis showed that the total content of four representative BCs (epimedin A, B, C and icariin decreased slightly or dramatically in two lines of E. sagittatum during leaf development. Transcriptional analysis revealed that two R2R3-MYB TFs (EsMYBA1 and EsMYBF1, together with a bHLH TF (EsGL3 and WD40 protein (EsTTG1, were supposed to coordinately regulate the anthocyanin and flavonol-derived BCs biosynthesis in leaves. Overexpression of EsFLS (flavonol synthase in tobacco resulted in increased flavonols content and decreased anthocyanins content in flowers. Moreover, EsMYB12 negatively correlated with the accumulation of the four BCs, and might act as a transcriptional repressor in the flavonoid pathway. Therefore, the anthocyanin pathway may coordinate with the flavonol-derived BCs pathway in Epimedium leaves. A better understanding of the flavonoid biosynthetic and regulatory mechanisms in E. sagittatum will facilitate functional characterization, metabolic engineering and molecular breeding studies of Epimedium species.

  7. The chemistry of subcritical water reactions of a hardwood derived lignin and lignin model compounds with nitrogen, hydrogen, carbon monoxide and carbon dioxide

    Science.gov (United States)

    Hill Bembenic, Meredith A.

    collected solids from the CO reactions appeared to be the most reacted (i.e., the most changed from the unreacted lignin) according to solid state 13C-NMR analysis, and the widest variety of products (methoxy-substituted phenolic compounds) were obtained when using CO according to GC/MS analysis. Therefore, reactions with CO were completed that varied the initial reaction pressure (300, 500 and 800 psi) in order to elucidate the effects of CO pressure. Similar conversion (≈54--58%) and DCM-soluble liquid product yields (≈53--62%) were obtained for the different pressure reactions, but the reactions with an initial pressure of 500 psi had the greatest change in aromaticity from the unreacted lignin. Additional reactions between Organosolv lignin and H2O with CO (initial pressure of 500 psi) were conducted where the reaction time was varied (15, 30 and 60 min.) to determine the effect of reaction time. Longer reaction time (60 min.) appeared to inhibit conversion to low molecular weight compounds (i.e., conversion and DCM-soluble yields were lower at ≈53% and ≈28%, respectively). Solid state 13C-NMR of collected residues also showed that there are losses in carbons representative of both guaiacyl and syringyl components as reaction time increases, which may indicate that methoxy groups are being cleaved or the products are reacting with each other (i.e., repolymerization) to form high molecular weight compounds as reaction time is increased. The role of H2O and the gases during the baseline reactions and the expanded CO reactions is not intuitive based on the results, so reactions with lignin model compounds (i.e., aromatic aldehydes represented by vanillin and syringaldehyde, aromatic ketones represented by acetovanillone and acetosyringone, and aromatic ethers represented by dibenzyl ether and 2-phenethyl phenyl ether) were completed to study this. From these results, the suggested reaction pathway of Organosolv lignin reactions in subcritical H2O with and without

  8. Chemical factors that control lignin polymerization.

    Science.gov (United States)

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

    2014-01-09

    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.

  9. Chapter 1: A Brief Introduction to Lignin Structure

    Energy Technology Data Exchange (ETDEWEB)

    Katahira, Rui [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Beckham, Gregg T [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Elder, Thomas J. [USDA-Forest Service

    2018-04-03

    Lignin is an alkyl-aromatic polymer found in the cell walls of terrestrial plants. Lignin provides structure and rigidity to plants, is a natural, highly effective barrier against microbial attack, and enables water and nutrient transport through plant tissues. Depending on the plant species, the constituents of lignin can vary considerably, leading to substantial diversity in lignin chemistry and structure. Despite nearly a century of research and development attempting to convert lignin into valuable products, lignin in most current and planned biorefinery contexts remains underutilized, most often being burned to generate heat and power. However, the drive towards effective lignin valorization processes has witnessed a significant resurgence in the past decade, catalyzed by advances in improved understanding of lignin chemistry, structure, and plasticity in parallel with new catalytic and biological approaches to valorize this important, prevalent biopolymer. As a preface to the subsequent chapters in this book, this chapter briefly highlights the known aspects of lignin structure.

  10. Biosynthetic origin of acetic acid using SNIF-NMR

    International Nuclear Information System (INIS)

    Boffo, Elisangela Fabiana; Ferreira, Antonio Gilberto

    2006-01-01

    The main purpose of this work is to describe the use of the technique Site-Specific Natural Isotopic Fractionation of hydrogen (SNIF-NMR), using 2 H and 1 H NMR spectroscopy, to investigate the biosynthetic origin of acetic acid in commercial samples of Brazilian vinegar. This method is based on the deuterium to hydrogen ratio at a specific position (methyl group) of acetic acid obtained by fermentation, through different biosynthetic mechanisms, which result in different isotopic ratios. We measured the isotopic ratio of vinegars obtained through C 3 , C 4 , and CAM biosynthetic mechanisms, blends of C 3 and C 4 (agrins) and synthetic acetic acid. (author)

  11. Systematic Parameterization of Lignin for the CHARMM Force Field

    Energy Technology Data Exchange (ETDEWEB)

    Vermaas, Joshua; Petridis, Loukas; Beckham, Gregg; Crowley, Michael

    2017-07-06

    Plant cell walls have three primary components, cellulose, hemicellulose, and lignin, the latter of which is a recalcitrant, aromatic heteropolymer that provides structure to plants, water and nutrient transport through plant tissues, and a highly effective defense against pathogens. Overcoming the recalcitrance of lignin is key to effective biomass deconstruction, which would in turn enable the use of biomass as a feedstock for industrial processes. Our understanding of lignin structure in the plant cell wall is hampered by the limitations of the available lignin forcefields, which currently only account for a single linkage between lignins and lack explicit parameterization for emerging lignin structures both from natural variants and engineered lignin structures. Since polymerization of lignin occurs via radical intermediates, multiple C-O and C-C linkages have been isolated , and the current force field only represents a small subset of lignin the diverse lignin structures found in plants. In order to take into account the wide range of lignin polymerization chemistries, monomers and dimer combinations of C-, H-, G-, and S-lignins as well as with hydroxycinnamic acid linkages were subjected to extensive quantum mechanical calculations to establish target data from which to build a complete molecular mechanics force field tuned specifically for diverse lignins. This was carried out in a GPU-accelerated global optimization process, whereby all molecules were parameterized simultaneously using the same internal parameter set. By parameterizing lignin specifically, we are able to more accurately represent the interactions and conformations of lignin monomers and dimers relative to a general force field. This new force field will enables computational researchers to study the effects of different linkages on the structure of lignin, as well as construct more accurate plant cell wall models based on observed statistical distributions of lignin that differ between

  12. In situ localization of phenylpropanoid biosynthetic mRNAs and proteins in Parsley (Petroselinum crispum)

    International Nuclear Information System (INIS)

    Reinold, S.; Hahlbrock, K.

    1997-01-01

    Using in situ RNA/RNA hybridization, enzyme immunolocalization, and histochemical techniques, several phenylpropanoid biosynthetic activities and products were localized in tissue sections from various aerial parts of parsley (Petroselinum crispum) plants at different developmental stages. The enzymes and corresponding mRNAs analyzed included two representatives of general phenylpropanoid metabolism: phenylalanine ammonia-lyase (PAL) and 4-coumarate: CoA ligase (4CL), and one representative each from two distinct branch pathways: chalcone synthase (CHS; flavonoids) and S-adenosyl-L-methionine: bergaptol O-methyltransferase (BMT; furanocoumarins). In almost all cases, the relative timing of accumulation differed greatly for mRNA and protein and indicated short expression periods and short half-lives for all mRNAs as compared to the proteins. PAL and 4CL occurred almost ubiquitously in cell type-specific patterns, and their mRNAs and proteins were always coordinately expressed, whereas the cell type-specific localization of flavonoid and furanocoumarin biosynthetic activities was to a large extent mutually exclusive. However, the distribution patterns of CHS and BMT, when superimposed, closely matched those of PAL and 4CL in nearly all tissues analysed, suggesting that the flavonoid and furanocoumarin pathways together constituted a large majority of the total phenylpropanoid biosynthetic activity. Differential sites of synthesis and accumulation indicating intercellular translocation were observed both for flavonoids and for furanocoumarins in oil ducts and the surrounding tissue. The widespread occurrence of both classes of compounds, as well as selected, pathway-specific mRNAs and enzymes, in many cell types of all parsley organs including various flower parts suggests additional functions beyond the previously established roles of flavonoids in UV protection and furanocoumarins in pathogen defence. (author)

  13. Connecting tropical river DOM and POM to the landscape with lignin

    Science.gov (United States)

    Hernes, Peter J.; Dyda, Rachael Y.; McDowell, William H.

    2017-12-01

    Tropical rivers account for two thirds of global fluxes of terrigenous organic matter to the oceans, yet because of their remote locations relative to most industrialized countries, they are poorly studied compared to temperate and even Arctic rivers. Further, most tropical river research has focused on large rivers like the Amazon or Congo, yet more than half of organic matter fluxes from tropical rivers comes from much smaller rivers. This study focuses on two such rivers in the Luquillo Experimental Forest of Puerto Rico, namely the Rio Mameyes and Rio Icacos, and uses time-series measurements of lignin biomarkers to put them in context with much bigger tropical rivers in the literature. Although lignin concentrations and carbon-normalized yields offer some distinction between mountainous vs. floodplain tropical river reaches, compositional differences appear to offer greater potential, including S:V vs. C:V plots that may capture the poorly-studied influence of palm trees, and (Ad:Al)s vs. (Ad:Al)v plots that may reflect differences in underlying mineralogy and degradation in soils. Even though dissolved and particulate lignin ultimately come from the same vegetation sources, comparison of dissolved and particulate lignin parameters within the two Puerto Rican rivers indicate that the pathways by which they end up in the same parcel of river water are largely decoupled. Across several particulate lignin studies in tropical rivers, mineral composition and concentration appears to exert a strong control on particulate lignin compositions and concentrations. Finally, the time-series nature of this study allows for new ways of analyzing dissolved lignin endmember compositions and degradation within the catchment. Plots of dissolved lignin parameters vs. lignin concentration reveal both the composition of "fresh" DOM that is likely mobilized from organic-rich soil surface layers along with the extent and trajectory of degradation of that signature that is possible

  14. Characterization of electrospun lignin based carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Poursorkhabi, Vida; Mohanty, Amar; Misra, Manjusri [School of Engineering, Thornbrough Building, University of Guelph, Guelph, N1G 2W1, Ontario (Canada); Bioproducts Discovery and Development Centre, Department of Plant Agriculture, Crop Science Building, University of Guelph, Guelph, N1G 2W1, Ontario (Canada)

    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.

  15. Characterization of electrospun lignin based carbon fibers

    International Nuclear Information System (INIS)

    Poursorkhabi, Vida; Mohanty, Amar; Misra, Manjusri

    2015-01-01

    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

  16. Reductive Catalytic Fractionation of Corn Stover Lignin

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Eric M.; Katahira, Rui; Reed, Michelle; Resch, Michael G.; Karp, Eric M.; Beckham, Gregg T.; Román-Leshkov, Yuriy

    2016-12-05

    Reductive catalytic fractionation (RCF) has emerged as an effective biomass pretreatment strategy to depolymerize lignin into tractable fragments in high yields. We investigate the RCF of corn stover, a highly abundant herbaceous feedstock, using carbon-supported Ru and Ni catalysts at 200 and 250 degrees C in methanol and, in the presence or absence of an acid cocatalyst (H3PO4 or an acidified carbon support). Three key performance variables were studied: (1) the effectiveness of lignin extraction as measured by the yield of lignin oil, (2) the yield of monomers in the lignin oil, and (3) the carbohydrate retention in the residual solids after RCF. The monomers included methyl coumarate/ferulate, propyl guaiacol/syringol, and ethyl guaiacol/syringol. The Ru and Ni catalysts performed similarly in terms of product distribution and monomer yields. The monomer yields increased monotonically as a function of time for both temperatures. At 6 h, monomer yields of 27.2 and 28.3% were obtained at 250 and 200 degrees C, respectively, with Ni/C. The addition of an acid cocatalysts to the Ni/C system increased monomer yields to 32% for acidified carbon and 38% for phosphoric acid at 200 degrees C. The monomer product distribution was dominated by methyl coumarate regardless of the use of the acid cocatalysts. The use of phosphoric acid at 200 degrees C or the high temperature condition without acid resulted in complete lignin extraction and partial sugar solubilization (up to 50%) thereby generating lignin oil yields that exceeded the theoretical limit. In contrast, using either Ni/C or Ni on acidified carbon at 200 degrees C resulted in moderate lignin oil yields of ca. 55%, with sugar retention values >90%. Notably, these sugars were amenable to enzymatic digestion, reaching conversions >90% at 96 h. Characterization studies on the lignin oils using two-dimensional heteronuclear single quantum coherence nuclear magnetic resonance and gel permeation chromatrography revealed

  17. Understanding the fast pyrolysis of lignin.

    Science.gov (United States)

    Patwardhan, Pushkaraj R; Brown, Robert C; Shanks, Brent H

    2011-11-18

    In the present study, pyrolysis of corn stover lignin was investigated by using a micro-pyrolyzer coupled with a GC-MS/FID (FID=flame ionization detector). The system has pyrolysis-vapor residence times of 15-20 ms, thus providing a regime of minimal secondary reactions. The primary pyrolysis product distribution obtained from lignin is reported. Over 84 % mass balance and almost complete closure on carbon balance is achieved. In another set of experiments, the pyrolysis vapors emerging from the micro-pyrolyzer are condensed to obtain lignin-derived bio-oil. The chemical composition of the bio-oil is analyzed by using GC-MS and gel permeation chromatography techniques. The comparison between results of two sets of experiments indicates that monomeric compounds are the primary pyrolysis products of lignin, which recombine after primary pyrolysis to produce oligomeric compounds. Further, the effect of minerals (NaCl, KCl, MgCl(2), and CaCl(2)) and temperature on the primary pyrolysis product distribution is investigated. The study provides insights into the fundamental mechanisms of lignin pyrolysis and a basis for developing more descriptive models of biomass pyrolysis. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Decoding how a soil bacterium extracts building blocks and metabolic energy from ligninolysis provides road map for lignin valorization

    Science.gov (United States)

    Varman, Arul M.; He, Lian; Follenfant, Rhiannon; Wu, Weihua; Wemmer, Sarah; Wrobel, Steven A.; Tang, Yinjie J.; Singh, Seema

    2016-01-01

    Sphingobium sp. SYK-6 is a soil bacterium boasting a well-studied ligninolytic pathway and the potential for development into a microbial chassis for lignin valorization. An improved understanding of its metabolism will help researchers in the engineering of SYK-6 for the production of value-added chemicals through lignin valorization. We used 13C-fingerprinting, 13C metabolic flux analysis (13C-MFA), and RNA-sequencing differential expression analysis to uncover the following metabolic traits: (i) SYK-6 prefers alkaline conditions, making it an efficient host for the consolidated bioprocessing of lignin, and it also lacks the ability to metabolize sugars or organic acids; (ii) the CO2 release (i.e., carbon loss) from the ligninolysis-based metabolism of SYK-6 is significantly greater than the CO2 release from the sugar-based metabolism of Escherichia coli; (iii) the vanillin catabolic pathway (which is the converging point of majority of the lignin catabolic pathways) is coupled with the tetrahydrofolate-dependent C1 pathway that is essential for the biosynthesis of serine, histidine, and methionine; (iv) catabolic end products of lignin (pyruvate and oxaloacetate) must enter the tricarboxylic acid (TCA) cycle first and then use phosphoenolpyruvate carboxykinase to initiate gluconeogenesis; and (v) 13C-MFA together with RNA-sequencing differential expression analysis establishes the vanillin catabolic pathway as the major contributor of NAD(P)H synthesis. Therefore, the vanillin catabolic pathway is essential for SYK-6 to obtain sufficient reducing equivalents for its healthy growth; cosubstrate experiments support this finding. This unique energy feature of SYK-6 is particularly interesting because most heterotrophs rely on the transhydrogenase, the TCA cycle, and the oxidative pentose phosphate pathway to obtain NADPH. PMID:27634497

  19. Lignin Formation and the Effects of Gravity: A New Approach

    Science.gov (United States)

    Lewis, Norman G.

    1997-01-01

    Two aspects of considerable importance in the enigmatic processes associated with lignification have made excellent progress. The first is that, even in a microgravity environment, compression wood formation, and hence altered lignin deposition, can be induced upon mechanically bending the stems of woody gymnosperms. It now needs to be established if an organism reorientating its woody stem tissue will generate this tissue in microgravity, in the absence of externally applied pressure. If it does not, then gravity has no effect on its formation, and instead it results from alterations in the stress gradient experienced by the organism impacted. The second area of progress involves establishing how the biochemical pathway to lignin is regulated, particularly with respect to selective monolignol biosynthesis. This is an important question since individual monomer deposition occurs in a temporally and spatially specific manner. In this regard, the elusive metabolic switch between E-p-coumaryl alcohol and E-coniferyl alcohol synthesis has been detected, the significance of which now needs to be defined at the enzyme and gene level. Switching between monolignol synthesis is important, since it is viewed to be a consequence of different perceptions by plants in the gravitational load experienced, and thus in the control of the type of lignification response. Additional experiments also revealed the rate-limiting processes involved in monolignol synthesis, and suggest that a biological system (involving metabolite concentrations, as well as enzymatic and gene (in)activation processes) is involved, rather than a single rate-limiting step.

  20. Fiber and lignin analysis in concentrate, forage, and feces

    DEFF Research Database (Denmark)

    Hindrichsen, I.K.; Kreuzer, M.; Madsen, Jørgen

    2006-01-01

    Hemicelluloses, cellulose, and lignin contents of contrasting feeds, with emphasis on concentrate ingredients and complete concentrates, were analyzed using the Van Soest detergent procedure (analyzing neutral detergent fiber, acid detergent fiber, and acid detergent lignin) and the enzymatic...

  1. New techniques for the characterization of lignins

    International Nuclear Information System (INIS)

    Javor, T.

    2001-09-01

    In the present work new techniques for the characterization of lignins, ligninsulfonates as well as lignin degradation products with capillary electrophoresis (CE), size exclusion chromatography (SEC) and mass spectrometry (ESI-MS, APCI-MS and MALDI-MS) are described. After an overview on wood and wood pulping the development of microemulsion electrokinetic chromatography (MEEKC) for the investigation of low-molecular-mass lignin degradation compounds is described. This method is suited for the analysis of phenolic compounds as well as for non-phenolic compounds in this kind of samples. Using a carrier electrolyte system consisting of 1-butanol/n-heptane/sodiumdodeylsulfate (SDS)/20 mM borate (6.61/0.81/1.66/90,29 % (w/w)) pH 9.2 it was possible to separate 14 lignin degradation compounds (2-methoxyphenol, 3,4,5-trimethoxyphenol, 2,6-dimethoxyphenol, 3,4-dimethoxybenzaldehyde, 3,4-dimethoxyacetophenone, 3,4,5-trimethoxybenzaldehyde, 3,4,5-trimethoxyacetophenone, 3-(3,4-dimethoxyphenyl)-2-propen-1-ol, 4-methoxyacetophenone, 3,5-Dimethoxy-4-hydroxyacetophenone, acetovanillone, syringaldehyde, vanillin, 4-hydroxybenzaldehyde and 1-(3-methoxy-4-hydroxyphenyl)-2-(2-methoxyphenoxy)-ethanol). In addition the advantages and disadvantages of microemulsions are discussed in comparison with carrier electrolytes containing micelles. Subsequently, the results from size exclusion chromatographic measurements are presented. SEC using modern high-performance poly(styrene-divinylbenzene) gels as stationary phase and 0.1 M NaOH as mobile phase allows efficient separations and good characterization of lignins and ligninsulfonates. Adsorption effects are practical negligible. SEC yields results which are independent of the charge of lignins or ligninsulfonates, so that this technique looks complementary to capillary electrophoresis. For the characterization of intact lignins and ligninsulfonates by capillary zone electrophoretic techniques, carrier electrolytes in the the pH range 10

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. De novo synthesis and decomposition of veratryl alcohol by a lignin-degrading basidiomycete

    Energy Technology Data Exchange (ETDEWEB)

    Lundquist, K; Kirk, T K

    1978-01-01

    In studies of the metabolism of lignin-related aromatics by the ligninolytic basidiomycete Phanerochaete chrysosporium (strain ME-446), a compound was consistently found (TLC) in chloroform extracts of cultures. The substance, identified as veratryl alcohol (1), was first suspected to be a non-metabilizable degradation product of the aromatics studied, which included various guaiacyl- and veratryl-type compounds. Veratryl alcohol itself, in fact, was included in the first experiments. Further investigation with cultures containing /sup 14/C-glucose as growth substrate revealed that 1 is synthesized de novo from glucose. Although the culture medium contained in addition to glucose 0.01 M phthalate or aconitate (buffers), and 0.6 mM L-asparagine (nutrient nitrogen), glucose was the sole source of veratryl alcohol carbon. Introduction of the purified biosynthetic /sup 14/C-veratryl alcohol into fresh cultures resulted in 40% decomposition to /sup 14/CO/sub 2/ in 20 days, showing that the fungus not only makes the compound, it also degrades it. Russell et al. found veratryl alcohol and veratraldehyde in cultures of a ligninolytic fungus (Polystictus versicolor), but considered them to be degradation products of the lignin-related aromatics or wood meal present in the cultures. Reports of synthesis or decomposition of veratryl alcohol by microorganisms were not found.

  4. Integration of Fermentation and Organic Synthesis: Studies of Roquefortine C and Biosynthetic Derivatives

    Science.gov (United States)

    Gober, Claire Marie

    Roquefortine C is one of the most ubiquitous indoline alkaloids of fungal origin. It has been isolated from over 30 different species of Penicillium fungi and has garnered attention in recent years for its role as a biosynthetic precursor to the triazaspirocyclic natural products glandicoline B, meleagrin, and oxaline. The triazaspirocyclic motif, which encompasses three nitrogen atoms attached to one quaternary carbon forming a spirocyclic scaffold, is a unique chemical moiety that has been shown to impart a wide array of biological activity, from anti-bacterial activity and antiproliferative activity against cancer cell lines to anti-biofouling against marine organisms. Despite the promise of these compounds in the pharmaceutical and materials industries, few syntheses of triazaspirocycles exist in the literature. The biosynthesis of roquefortine C-derived triazaspirocycles, however, provides inspiration for the synthesis of these compounds, namely through a nitrone-promoted transannular rearrangement. This type of internal rearrangement has never been carried out synthetically and would provide an efficient stereoselective synthesis of triazaspirocycles. This work encompasses efforts towards elucidating the biosynthetic pathway of roquefortine C-derived triazaspirocycles as well as synthetic efforts towards the construction of triazaspirocycles. Chapter 1 will discuss a large-scale fermentation procedure for the production of roquefortine C from Penicillium crustosum. Chapters 2 and 3 explore (through enzymatic and synthetic means, respectively) the formation of the key indoline nitrone moiety required for the proposed transannular rearrangement. Finally, chapter 4 will discuss synthetic efforts towards the synthesis of triazaspirocycles. This work has considerably enhanced our understanding of the roquefortine C biosynthetic pathway and the unique chemistry of this natural product, and our efforts towards the synthesis of triazaspirocycles will facilitate the

  5. Characterization and genomic analysis of kraft lignin biodegradation by the beta-proteobacterium Cupriavidus basilensis B-8

    Directory of Open Access Journals (Sweden)

    Shi Yan

    2013-01-01

    Full Text Available Abstract Background Lignin materials are abundant and among the most important potential sources for biofuel production. Development of an efficient lignin degradation process has considerable potential for the production of a variety of chemicals, including bioethanol. However, lignin degradation using current methods is inefficient. Given their immense environmental adaptability and biochemical versatility, bacterial could be used as a valuable tool for the rapid degradation of lignin. Kraft lignin (KL is a polymer by-product of the pulp and paper industry resulting from alkaline sulfide treatment of lignocellulose, and it has been widely used for lignin-related studies. Results Beta-proteobacterium Cupriavidus basilensis B-8 isolated from erosive bamboo slips displayed substantial KL degradation capability. With initial concentrations of 0.5–6 g L-1, at least 31.3% KL could be degraded in 7 days. The maximum degradation rate was 44.4% at the initial concentration of 2 g L-1. The optimum pH and temperature for KL degradation were 7.0 and 30°C, respectively. Manganese peroxidase (MnP and laccase (Lac demonstrated their greatest level of activity, 1685.3 U L-1 and 815.6 U L-1, at the third and fourth days, respectively. Many small molecule intermediates were formed during the process of KL degradation, as determined using GC-MS analysis. In order to perform metabolic reconstruction of lignin degradation in this bacterium, a draft genome sequence for C. basilensis B-8 was generated. Genomic analysis focused on the catabolic potential of this bacterium against several lignin-derived compounds. These analyses together with sequence comparisons predicted the existence of three major metabolic pathways: β-ketoadipate, phenol degradation, and gentisate pathways. Conclusion These results confirmed the capability of C. basilensis B-8 to promote KL degradation. Whole genomic sequencing and systematic analysis of the C. basilensis B-8 genome

  6. Analytical methods for lignin characterization - Differential scanning calorimetry

    NARCIS (Netherlands)

    Koullas, D.P.; Koukios, E.G.; Avgerinos, E.; Abaecherli, A.; Gosselink, R.; Vasile, C.; Lehnen, R.; Saake, B.; Suren, J.

    2006-01-01

    Results of a round robin on lignin thermal analyses are reported. Six laboratories have conducted thermal analyses of four lignin types to determine their cp values and softening points, and to study the thermal behaviour, materials endo- and exotherms included. The lignin types examined were wood

  7. Advances in the chemical utilization of alkali lignin

    International Nuclear Information System (INIS)

    Van der Klashorst, G.H.

    1985-06-01

    Large quantities of alkali lignin are produced as by-products by the South African pulping industry. The potential utilization of industrial soda/anthraquinone (soda/AQ) eucalyptus, kraft pine and soda bagasse lignin was subsequently investigated. The molecular mass distributions of the three lignins were similar when determined by high pressure gel permeation chromatography (HP-GPC). The quantitative and quanlitative occurrence of various low molecular mass lignin fragments in the different spent liquors, on the other hand, indicated that the three lignins have substantial chemical differences. Analysis of the purified degraded lignins by NMR, methoxyl content determinations, elemental analysis, carbohydrate content determinations etc., quantified various of the chemical properties of the lignin. The properties of the three lignins were ultimately used to make recommendations regarding the potential use of each lignin. One such application was investigated and it was shown that soda bagasse lignin can be used successfully in phenol formaldehyde resin applications. The reaction of formaldehyde with lignin model compounds in acidic medium was also investigated. This reaction was shown to give fast crosslinking of alkyl substituted phenolic and etherified phenolic lignin model compounds at positions meta to the aromatic hydroxy groups

  8. Using biomimetic cell wall models to identify new plant lignin bioengineering targets for improving forage and biomass utilization

    Science.gov (United States)

    Bioengineering of lignin to contain atypical components derived from other metabolic pathways is increasingly being pursued to custom design lignified cell walls that are inherently more digestible by livestock or more easily pretreated and saccharified for biofuel production. Because plants produce...

  9. Identifying new lignin bioengineering targets for improving biomass and forage utilization: a review of biomimetic studies with maize cell walls

    Science.gov (United States)

    Bioengineering of lignin to contain atypical components derived from other metabolic pathways is increasingly being pursued to custom design lignified cell walls that are more readily pretreated and saccharified for biofuel production or easily digested by livestock. Because plants produce such a di...

  10. The Arabidopsis histone chaperone FACT is required for stress-induced expression of anthocyanin biosynthetic genes.

    Science.gov (United States)

    Pfab, Alexander; Breindl, Matthias; Grasser, Klaus D

    2018-03-01

    The histone chaperone FACT is involved in the expression of genes encoding anthocyanin biosynthetic enzymes also upon induction by moderate high-light and therefore contributes to the stress-induced plant pigmentation. The histone chaperone FACT consists of the SSRP1 and SPT16 proteins and associates with transcribing RNAPII (RNAPII) along the transcribed region of genes. FACT can promote transcriptional elongation by destabilising nucleosomes in the path of RNA polymerase II, thereby facilitating efficient transcription of chromatin templates. Transcript profiling of Arabidopsis plants depleted in SSRP1 or SPT16 demonstrates that only a small subset of genes is differentially expressed relative to wild type. The majority of these genes is either up- or down-regulated in both the ssrp1 and spt16 plants. Among the down-regulated genes, those encoding enzymes of the biosynthetic pathway of the plant secondary metabolites termed anthocyanins (but not regulators of the pathway) are overrepresented. Upon exposure to moderate high-light stress several of these genes are up-regulated to a lesser extent in ssrp1/spt16 compared to wild type plants, and accordingly the mutant plants accumulate lower amounts of anthocyanin pigments. Moreover, the expression of SSRP1 and SPT16 is induced under these conditions. Therefore, our findings indicate that FACT is a novel factor required for the accumulation of anthocyanins in response to light-induction.

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

    NARCIS (Netherlands)

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

    2016-01-01

    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

  12. Comparison of the acetyl bromide spectrophotometric method with other analytical lignin methods for determining lignin concentration in forage samples.

    Science.gov (United States)

    Fukushima, Romualdo S; Hatfield, Ronald D

    2004-06-16

    Present analytical methods to quantify lignin in herbaceous plants are not totally satisfactory. A spectrophotometric method, acetyl bromide soluble lignin (ABSL), has been employed to determine lignin concentration in a range of plant materials. In this work, lignin extracted with acidic dioxane was used to develop standard curves and to calculate the derived linear regression equation (slope equals absorptivity value or extinction coefficient) for determining the lignin concentration of respective cell wall samples. This procedure yielded lignin values that were different from those obtained with Klason lignin, acid detergent acid insoluble lignin, or permanganate lignin procedures. Correlations with in vitro dry matter or cell wall digestibility of samples were highest with data from the spectrophotometric technique. The ABSL method employing as standard lignin extracted with acidic dioxane has the potential to be employed as an analytical method to determine lignin concentration in a range of forage materials. It may be useful in developing a quick and easy method to predict in vitro digestibility on the basis of the total lignin content of a sample.

  13. Hydrothermal Liquefaction of Enzymatic Hydrolysis Lignin: Biomass Pretreatment Severity Affects Lignin Valorization

    DEFF Research Database (Denmark)

    Jensen, Mads M.; Djajadi, Demi T.; Torri, Cristian

    2018-01-01

    Alkalinehydrothermal liquefaction (HTL) of lignin-rich enzymatichydrolysis residues (EnzHR) from wheat straw and Miscanthusx giganteus was performed at 255, 300, and 345 °C to investigate valorization of this side-stream from second-generation bioethanol production. The EnzHR were from biomass...... contributed with additional chemical information as well as confirming trends seen from quantified monomers. This work is relevant for future lignin valorization in biorefineries based on current second-generation bioethanol production....

  14. Environmental economics of lignin derived transport fuels.

    Science.gov (United States)

    Obydenkova, Svetlana V; Kouris, Panos D; Hensen, Emiel J M; Heeres, Hero J; Boot, Michael D

    2017-11-01

    This paper explores the environmental and economic aspects of fast pyrolytic conversion of lignin, obtained from 2G ethanol plants, to transport fuels for both the marine and automotive markets. Various scenarios are explored, pertaining to aggregation of lignin from several sites, alternative energy carries to replace lignin, transport modalities, and allocation methodology. The results highlight two critical factors that ultimately determine the economic and/or environmental fuel viability. The first factor, the logistics scheme, exhibited the disadvantage of the centralized approach, owing to prohibitively expensive transportation costs of the low energy-dense lignin. Life cycle analysis (LCA) displayed the second critical factor related to alternative energy carrier selection. Natural gas (NG) chosen over additional biomass boosts well-to-wheel greenhouse gas emissions (WTW GHG) to a level incompatible with the reduction targets set by the U.S. renewable fuel standard (RFS). Adversely, the process' economics revealed higher profits vs. fossil energy carrier. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  15. Naturally p-Hydroxybenzoylated Lignins in Palms

    Science.gov (United States)

    Fachuang Lu; Steven D. Karlen; Matt Regner; Hoon Kim; Sally A. Ralph; Run-Cang Sun; Ken-ichi Kuroda; Mary Ann Augustin; Raymond Mawson; Henry Sabarez; Tanoj Singh; Gerardo Jimenez-Monteon; Sarani Zakaria; Stefan Hill; Philip J. Harris; Wout Boerjan; Curtis G. Wilkerson; Shawn D. Mansfield; John Ralph

    2015-01-01

    The industrial production of palm oil concurrently generates a substantial amount of empty fruit bunch (EFB) fibers that could be used as a feedstock in a lignocellulose based biorefinery. Lignin byproducts generated by this process may offer opportunities for the isolation of value-added products, such as p-hydroxybenzoate (pBz),...

  16. Catalytic depolymerization of lignin in supercritical ethanol

    NARCIS (Netherlands)

    Huang, X.; Koranyi, T.I.; Boot, M.D.; Hensen, E.J.M.

    2014-01-01

    One-step valorization of soda lignin in supercritical ethanol using a CuMgAlOx catalyst results in high monomer yield (23 wt¿%) without char formation. Aromatics are the main products. The catalyst combines excellent deoxygenation with low ring-hydrogenation activity. Almost half of the monomer

  17. Enzymology and molecular biology of lignin degradation

    Science.gov (United States)

    D. Cullen; P.J. Kersten

    2004-01-01

    This review provides an overview of the physiology and genetics of lignin degradation by white rot basidiomycetes. Emphasis is on recent advances and the reader is referred to earlier comprehensive reviews for historical perspective and background (Kirk and Farrell 1987; Gold and Alic 1993; Higuchi 1993; Cullen and Kersten 1996; Cullen 1997). Recent completion of a...

  18. Lignin-blocking treatment of biomass and uses thereof

    Science.gov (United States)

    Yang, Bin [Hanover, NH; Wyman, Charles E [Norwich, VT

    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.

  19. Global analysis of biosynthetic gene clusters reveals vast potential of secondary metabolite production in Penicillium species

    DEFF Research Database (Denmark)

    Nielsen, Jens Christian; Grijseels, Sietske; Prigent, Sylvain

    2017-01-01

    Filamentous fungi produce a wide range of bioactive compounds with important pharmaceutical applications, such as antibiotic penicillins and cholesterol-lowering statins. However, less attention has been paid to fungal secondary metabolites compared to those from bacteria. In this study, we...... sequenced the genomes of 9 Penicillium species and, together with 15 published genomes, we investigated the secondary metabolism of Penicillium and identified an immense, unexploited potential for producing secondary metabolites by this genus. A total of 1,317 putative biosynthetic gene clusters (BGCs) were......-referenced the predicted pathways with published data on the production of secondary metabolites and experimentally validated the production of antibiotic yanuthones in Penicillia and identified a previously undescribed compound from the yanuthone pathway. This study is the first genus-wide analysis of the genomic...

  20. Diesel-soluble lignin oils and methods of their production

    DEFF Research Database (Denmark)

    2016-01-01

    Solvent consumption in supercritical ethanol, propanol or butanol treatment of either refined pre-extracted lignin or comparatively impure lignin-rich solid residual from hydrothermally pretreated lignocellulosic biomass can be minimized by conducting the reaction at very high loading of lignin...... to solvent. Comparatively impure, crude lignin- rich solid residual can be directly converted by supercritical alcohol treatment to significantly diesel-soluble lignin oil without requirement for pre-extraction or pre- solubilisation of lignin or for added reaction promoters such as catalysts, hydrogen donor...... co-solvents, acids, based or H2 gas. O:C ratio of product oil can readily be obtained using crude lignin residual in such a process at levels 0.20 or lower....

  1. Reactions of Lignin Model Compounds in Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Natural Product Biosynthetic Diversity and Comparative Genomics of the Cyanobacteria.

    Science.gov (United States)

    Dittmann, Elke; Gugger, Muriel; Sivonen, Kaarina; Fewer, David P

    2015-10-01

    Cyanobacteria are an ancient lineage of slow-growing photosynthetic bacteria and a prolific source of natural products with intricate chemical structures and potent biological activities. The bulk of these natural products are known from just a handful of genera. Recent efforts have elucidated the mechanisms underpinning the biosynthesis of a diverse array of natural products from cyanobacteria. Many of the biosynthetic mechanisms are unique to cyanobacteria or rarely described from other organisms. Advances in genome sequence technology have precipitated a deluge of genome sequences for cyanobacteria. This makes it possible to link known natural products to biosynthetic gene clusters but also accelerates the discovery of new natural products through genome mining. These studies demonstrate that cyanobacteria encode a huge variety of cryptic gene clusters for the production of natural products, and the known chemical diversity is likely to be just a fraction of the true biosynthetic capabilities of this fascinating and ancient group of organisms. Copyright © 2015. Published by Elsevier Ltd.

  3. Catalytic Oxidation and Depolymerization of Lignin in Aqueous Ionic Liquid

    International Nuclear Information System (INIS)

    Das, Lalitendu; Xu, Siquan; Shi, Jian

    2017-01-01

    Lignin is an integral part of the plant cell wall, which provides rigidity to plants, also contributes to the recalcitrance of the lignocellulosic biomass to biochemical and biological deconstruction. Lignin is a promising renewable feedstock for aromatic chemicals; however, an efficient and economic lignin depolymerization method needs to be developed to enable the conversion. In this study, we investigated the depolymerization of alkaline lignin in aqueous 1-ethyl-3-methylimidazolium acetate [C 2 C 1 Im][OAc] under oxidizing conditions. Seven different transition metal catalysts were screened in presence of H 2 O 2 as oxidizing agent in a batch reactor. CoCl 2 and Nb 2 O 5 proved to be the most effective catalysts in degrading lignin to aromatic compounds. A central composite design was used to optimize the catalyst loading, H 2 O 2 concentration, and temperature for product formation. Results show that lignin was depolymerized, and the major degradation products found in the extracted oil were guaiacol, syringol, vanillin, acetovanillone, and homovanillic acid. Lignin streams were characterized by Fourier transform infrared spectroscopy and gel permeation chromatography to determine effects of the experimental parameters on lignin depolymerization. The weight-average molecular weight (M w ) of liquid stream lignin after oxidation, for CoCl 2 and Nb 2 O 5 catalysts were 1,202 and 1,520 g mol −1 , respectively, lower than that of Kraft lignin. Polydispersity index of the liquid stream lignin increased as compared with Kraft lignin, indicating wide span of the molecular weight distribution as a result of lignin depolymerization. Results from this study provide insights into the role of oxidant and transition metal catalysts and the oxidative degradation reaction sequence of lignin toward product formation in presence of aqueous ionic liquid.

  4. Lignin depolymerization by fungal secretomes and a microbial sink

    Energy Technology Data Exchange (ETDEWEB)

    Salvachúa, Davinia; Katahira, Rui; Cleveland, Nicholas S.; Khanna, Payal; Resch, Michael G.; Black, Brenna A.; Purvine, Samuel O.; Zink, Erika M.; Prieto, Alicia; Martínez, María J.; Martínez, Angel T.; Simmons, Blake A.; Gladden, John M.; Beckham, Gregg T.

    2016-08-25

    In Nature, powerful oxidative enzymes secreted by white rot fungi and some bacteria catalyze lignin depolymerization and some microbes are able to catabolize the resulting aromatic compounds as carbon and energy sources. Taken together, these two processes offer a potential route for microbial valorization of lignin. However, many challenges remain in realizing this concept, including that oxidative enzymes responsible for lignin depolymerization also catalyze polymerization of low molecular weight (LMW) lignin. Here, multiple basidiomycete secretomes were screened for ligninolytic enzyme activities in the presence of a residual lignin solid stream from a corn stover biorefinery, dubbed DMR-EH (Deacetylation, Mechanical Refining, and Enzymatic Hydrolysis) lignin. Two selected fungal secretomes, with high levels of laccases and peroxidases, were utilized for DMR-EH lignin depolymerization assays. The secretome from Pleurotus eryngii, which exhibited the highest laccase activity, reduced the lignin average molecular weight by 63% and 75% at pH 7 compared to the Mw of the control treated at the same conditions and the initial DMR-EH lignin, respectively, and was applied in further depolymerization assays as a function of time. As repolymerization was observed after 3 days of incubation, an aromatic-catabolic microbe (Pseudomonas putida KT2440) was incubated with the fungal secretome and DMR-EH lignin. These experiments demonstrated that the presence of the bacterium enhances lignin depolymerization, likely due to bacterial catabolism of LMW lignin, which may partially prevent repolymerization. In addition, proteomics was also applied to the P. eryngii secretome to identify the enzymes present in the fungal cocktail utilized for the depolymerization assays, which highlighted a significant number of glucose/ methanol/choline (GMC) oxidoreductases and laccases. Overall, this study demonstrates that ligninolytic enzymes can be used to partially depolymerize a solid, high

  5. Catalytic Oxidation and Depolymerization of Lignin in Aqueous Ionic Liquid

    Energy Technology Data Exchange (ETDEWEB)

    Das, Lalitendu [Biosystems and Agricultural Engineering, University of Kentucky, Lexington, KY (United States); Xu, Siquan [Biosystems and Agricultural Engineering, University of Kentucky, Lexington, KY (United States); College of Chemical Engineering, Nanjing Forestry University, Nanjing (China); Shi, Jian, E-mail: j.shi@uky.edu [Biosystems and Agricultural Engineering, University of Kentucky, Lexington, KY (United States)

    2017-08-10

    Lignin is an integral part of the plant cell wall, which provides rigidity to plants, also contributes to the recalcitrance of the lignocellulosic biomass to biochemical and biological deconstruction. Lignin is a promising renewable feedstock for aromatic chemicals; however, an efficient and economic lignin depolymerization method needs to be developed to enable the conversion. In this study, we investigated the depolymerization of alkaline lignin in aqueous 1-ethyl-3-methylimidazolium acetate [C{sub 2}C{sub 1}Im][OAc] under oxidizing conditions. Seven different transition metal catalysts were screened in presence of H{sub 2}O{sub 2} as oxidizing agent in a batch reactor. CoCl{sub 2} and Nb{sub 2}O{sub 5} proved to be the most effective catalysts in degrading lignin to aromatic compounds. A central composite design was used to optimize the catalyst loading, H{sub 2}O{sub 2} concentration, and temperature for product formation. Results show that lignin was depolymerized, and the major degradation products found in the extracted oil were guaiacol, syringol, vanillin, acetovanillone, and homovanillic acid. Lignin streams were characterized by Fourier transform infrared spectroscopy and gel permeation chromatography to determine effects of the experimental parameters on lignin depolymerization. The weight-average molecular weight (M{sub w}) of liquid stream lignin after oxidation, for CoCl{sub 2} and Nb{sub 2}O{sub 5} catalysts were 1,202 and 1,520 g mol{sup −1}, respectively, lower than that of Kraft lignin. Polydispersity index of the liquid stream lignin increased as compared with Kraft lignin, indicating wide span of the molecular weight distribution as a result of lignin depolymerization. Results from this study provide insights into the role of oxidant and transition metal catalysts and the oxidative degradation reaction sequence of lignin toward product formation in presence of aqueous ionic liquid.

  6. Comprehensive transcriptome analyses correlated with untargeted metabolome reveal differentially expressed pathways in response to cell wall alterations.

    Science.gov (United States)

    Reem, Nathan T; Chen, Han-Yi; Hur, Manhoi; Zhao, Xuefeng; Wurtele, Eve Syrkin; Li, Xu; Li, Ling; Zabotina, Olga

    2018-03-01

    This research provides new insights into plant response to cell wall perturbations through correlation of transcriptome and metabolome datasets obtained from transgenic plants expressing cell wall-modifying enzymes. Plants respond to changes in their cell walls in order to protect themselves from pathogens and other stresses. Cell wall modifications in Arabidopsis thaliana have profound effects on gene expression and defense response, but the cell signaling mechanisms underlying these responses are not well understood. Three transgenic Arabidopsis lines, two with reduced cell wall acetylation (AnAXE and AnRAE) and one with reduced feruloylation (AnFAE), were used in this study to investigate the plant responses to cell wall modifications. RNA-Seq in combination with untargeted metabolome was employed to assess differential gene expression and metabolite abundance. RNA-Seq results were correlated with metabolite abundances to determine the pathways involved in response to cell wall modifications introduced in each line. The resulting pathway enrichments revealed the deacetylation events in AnAXE and AnRAE plants induced similar responses, notably, upregulation of aromatic amino acid biosynthesis and changes in regulation of primary metabolic pathways that supply substrates to specialized metabolism, particularly those related to defense responses. In contrast, genes and metabolites of lipid biosynthetic pathways and peroxidases involved in lignin polymerization were downregulated in AnFAE plants. These results elucidate how primary metabolism responds to extracellular stimuli. Combining the transcriptomics and metabolomics datasets increased the power of pathway prediction, and demonstrated the complexity of pathways involved in cell wall-mediated signaling.

  7. Evolutionary systems biology of amino acid biosynthetic cost in yeast.

    Directory of Open Access Journals (Sweden)

    Michael D Barton

    2010-08-01

    Full Text Available Every protein has a biosynthetic cost to the cell based on the synthesis of its constituent amino acids. In order to optimise growth and reproduction, natural selection is expected, where possible, to favour the use of proteins whose constituents are cheaper to produce, as reduced biosynthetic cost may confer a fitness advantage to the organism. Quantifying the cost of amino acid biosynthesis presents challenges, since energetic requirements may change across different cellular and environmental conditions. We developed a systems biology approach to estimate the cost of amino acid synthesis based on genome-scale metabolic models and investigated the effects of the cost of amino acid synthesis on Saccharomyces cerevisiae gene expression and protein evolution. First, we used our two new and six previously reported measures of amino acid cost in conjunction with codon usage bias, tRNA gene number and atomic composition to identify which of these factors best predict transcript and protein levels. Second, we compared amino acid cost with rates of amino acid substitution across four species in the genus Saccharomyces. Regardless of which cost measure is used, amino acid biosynthetic cost is weakly associated with transcript and protein levels. In contrast, we find that biosynthetic cost and amino acid substitution rates show a negative correlation, but for only a subset of cost measures. In the economy of the yeast cell, we find that the cost of amino acid synthesis plays a limited role in shaping transcript and protein expression levels compared to that of translational optimisation. Biosynthetic cost does, however, appear to affect rates of amino acid evolution in Saccharomyces, suggesting that expensive amino acids may only be used when they have specific structural or functional roles in protein sequences. However, as there appears to be no single currency to compute the cost of amino acid synthesis across all cellular and environmental

  8. Enhanced lignin monomer production caused by cinnamic Acid and its hydroxylated derivatives inhibits soybean root growth.

    Directory of Open Access Journals (Sweden)

    Rogério Barbosa Lima

    Full Text Available Cinnamic acid and its hydroxylated derivatives (p-coumaric, caffeic, ferulic and sinapic acids are known allelochemicals that affect the seed germination and root growth of many plant species. Recent studies have indicated that the reduction of root growth by these allelochemicals is associated with premature cell wall lignification. We hypothesized that an influx of these compounds into the phenylpropanoid pathway increases the lignin monomer content and reduces the root growth. To confirm this hypothesis, we evaluated the effects of cinnamic, p-coumaric, caffeic, ferulic and sinapic acids on soybean root growth, lignin and the composition of p-hydroxyphenyl (H, guaiacyl (G and syringyl (S monomers. To this end, three-day-old seedlings were cultivated in nutrient solution with or without allelochemical (or selective enzymatic inhibitors of the phenylpropanoid pathway in a growth chamber for 24 h. In general, the results showed that 1 cinnamic, p-coumaric, caffeic and ferulic acids reduced root growth and increased lignin content; 2 cinnamic and p-coumaric acids increased p-hydroxyphenyl (H monomer content, whereas p-coumaric, caffeic and ferulic acids increased guaiacyl (G content, and sinapic acid increased sinapyl (S content; 3 when applied in conjunction with piperonylic acid (PIP, an inhibitor of the cinnamate 4-hydroxylase, C4H, cinnamic acid reduced H, G and S contents; and 4 when applied in conjunction with 3,4-(methylenedioxycinnamic acid (MDCA, an inhibitor of the 4-coumarate:CoA ligase, 4CL, p-coumaric acid reduced H, G and S contents, whereas caffeic, ferulic and sinapic acids reduced G and S contents. These results confirm our hypothesis that exogenously applied allelochemicals are channeled into the phenylpropanoid pathway causing excessive production of lignin and its main monomers. By consequence, an enhanced stiffening of the cell wall restricts soybean root growth.

  9. Novel seed coat lignins in the Cactaceae: structure, distribution and implications for the evolution of lignin diversity.

    Science.gov (United States)

    Chen, Fang; Tobimatsu, Yuki; Jackson, Lisa; Nakashima, Jin; Ralph, John; Dixon, Richard A

    2013-01-01

    We have recently described a hitherto unsuspected catechyl lignin polymer (C-lignin) in the seed coats of Vanilla orchid and in cacti of one genus, Melocactus (Chen et al., Proc. Natl. Acad. Sci. USA. 2012, 109, 1772-1777.). We have now determined the lignin types in the seed coats of 130 different cactus species. Lignin in the vegetative tissues of cacti is of the normal guaiacyl/syringyl (G/S) type, but members of most genera within the subfamily Cactoidae possess seed coat lignin of the novel C-type only, which we show is a homopolymer formed by endwise β-O-4-coupling of caffeyl alcohol monomers onto the growing polymer resulting in benzodioxane units. However, the species examined within the genera Coryphantha, Cumarinia, Escobaria and Mammillaria (Cactoideae) mostly had normal G/S lignin in their seeds, as did all six species in the subfamily Opuntioidae that were examined. Seed coat lignin composition is still evolving in the Cactaceae, as seeds of one Mammillaria species (M. lasiacantha) possess only C-lignin, three Escobaria species (E. dasyacantha, E. lloydii and E. zilziana) contain an unusual lignin composed of 5-hydroxyguaiacyl units, the first report of such a polymer that occurs naturally in plants, and seeds of some species contain no lignin at all. We discuss the implications of these findings for the mechanisms that underlie the biosynthesis of these newly discovered lignin types. © 2012 The Authors The Plant Journal © 2012 Blackwell Publishing Ltd.

  10. Higher transcription levels in ascorbic acid biosynthetic and recycling genes were associated with higher ascorbic acid accumulation in blueberry.

    Science.gov (United States)

    Liu, Fenghong; Wang, Lei; Gu, Liang; Zhao, Wei; Su, Hongyan; Cheng, Xianhao

    2015-12-01

    In our preliminary study, the ripe fruits of two highbush blueberry (Vaccinium corymbosum L.) cultivars, cv 'Berkeley' and cv 'Bluecrop', were found to contain different levels of ascorbic acid. However, factors responsible for these differences are still unknown. In the present study, ascorbic acid content in fruits was compared with expression profiles of ascorbic acid biosynthetic and recycling genes between 'Bluecrop' and 'Berkeley' cultivars. The results indicated that the l-galactose pathway was the predominant route of ascorbic acid biosynthesis in blueberry fruits. Moreover, higher expression levels of the ascorbic acid biosynthetic genes GME, GGP, and GLDH, as well as the recycling genes MDHAR and DHAR, were associated with higher ascorbic acid content in 'Bluecrop' compared with 'Berkeley', which indicated that a higher efficiency ascorbic acid biosynthesis and regeneration was likely to be responsible for the higher ascorbic acid accumulation in 'Bluecrop'. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. antiSMASH 3.0—a comprehensive resource for the genome mining of biosynthetic gene clusters

    DEFF Research Database (Denmark)

    Weber, Tilmann; Blin, Kai; Duddela, Srikanth

    2015-01-01

    Microbial secondary metabolism constitutes a rich source of antibiotics, chemotherapeutics, insecticides and other high-value chemicals. Genome mining of gene clusters that encode the biosynthetic pathways for these metabolites has become a key methodology for novel compound discovery. In 2011, we...... introduced antiSMASH, a web server and stand-alone tool for the automatic genomic identification and analysis of biosynthetic gene clusters, available at http://antismash.secondarymetabolites.org. Here, we present version 3.0 of antiSMASH, which has undergone major improvements. A full integration...... of the recently published ClusterFinder algorithm now allows using this probabilistic algorithm to detect putative gene clusters of unknown types. Also, a new dereplication variant of the ClusterBlast module now identifies similarities of identified clusters to any of 1172 clusters with known end products...

  12. Reductive deconstruction of organosolv lignin catalyzed by zeolite supported nickel nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kasakov, Stanislav; Shi, Hui; Camaioni, Donald M.; Zhao, Chen; Barath, Eszter; Jentys, Andreas; Lercher, Johannes A.

    2015-11-01

    Mechanistic aspects of deconstruction and hydrodeoxygenation of organosolv lignin using supported Ni catalysts with (Ni/HZSM-5 and Ni/HBEA) and without Brønsted acid sites (Ni/SiO2) are reported. Lignin was deconstructed and converted to saturated cyclic hydrocarbons ranging from C5 to C14. In the one-stage reaction, full conversion with total yield of 70 ± 5 wt.% saturated hydrocarbons was achieved at 593 K and 20 bar H2. The organosolv lignin used consists of seven to eight monolignol subunits and has an average molecular weight of ca. 1200 g mol-1. The monolignols were mainly guaiacyl, syringyl and phenylcoumaran, randomly interconnected through β-O-4, 4-O-5, β-1, 5-5’ and β-β ether bonds. In situ IR spectroscopy was used to follow the changes in lignin constituents during reaction. The proposed reaction pathways for the catalytic transformation of this organosolv lignin to alkanes start with the hydrogenolysis of aryl alkyl ether bonds, followed by hydrogenation of the aromatic compounds on Ni to cyclic alcohols. Oxygen is removed from the alcohols via dehydration on Brønsted acid sites to yield cyclic alkenes that are further hydrogenated to alkanes. Formation of condensation products may occur via intermolecular recombination of aromatic monomers or alkylation of aromatic compounds by alkenes. The financial support from TUM-PNNL cooperation project “Development of new methods for in situ characterization in liquid phase reactions” (CN-177939) is highly appreciated. The work by S.K., H.S., and J.A.L was partially supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences.

  13. Importance of Oceanian small mountainous rivers (SMRs) in global land-to-ocean output of lignin and modern biospheric carbon.

    Science.gov (United States)

    Bao, Hongyan; Lee, Tsung-Yu; Huang, Jr-Chuan; Feng, Xiaojuan; Dai, Minhan; Kao, Shuh-Ji

    2015-11-20

    The land-to-ocean export of particulate organic carbon (POC) connects carbon flow from the atmosphere through land to the ocean, of which the contemporary fraction that reaches the deep sea for burial may effectively affect atmospheric CO2. In this regard, small mountainous rivers (SMRs) in Oceania, a global erosion hotspot driven by torrential typhoon rain and active earthquakes are potentially important. Here we measured typhoon lignin discharges for Taiwan SMRs. We found that the particulate lignin export in 96 hours by a single SMR amounting to ~20% of the annual export by Mississippi River. The yearly particulate lignin discharge from Taiwan Island (35,980 km(2)) is governed by the frequency and magnitude of typhoon; thus, the historical lignin export ranged widely from 1.5 to 99.7 Gg yr(-1), which resulted in a 10-100 times higher areal yield relative to non-Oceanian rivers. The lignin-derived modern POC output from Oceania region is 37 ± 21 Tg C yr(-1), account for approximately 20% of the annual modern POC export from global rivers. Coupled with the hyperpycnal pathway, the forested watersheds of SMRs in Oceania may serve as a giant factory to rapidly produce and efficiently convey modern POC into deep sea for sequestration.

  14. Solvothermal conversion of technical lignins over NiMo catalysts

    DEFF Research Database (Denmark)

    Ghafarnejad Parto, Soheila; Christensen, Jakob Munkholt; Pedersen, Lars Saaby

    Scope: Lignin, cellulose and hemicellulose are the main constituents of plants cell walls. Lignin is an aromatic rich compound, composed of phenolic building blocks. Depending on the method used for isolation of lignin from cellulose and hemicellulose, several types of technical lignin are availa......Scope: Lignin, cellulose and hemicellulose are the main constituents of plants cell walls. Lignin is an aromatic rich compound, composed of phenolic building blocks. Depending on the method used for isolation of lignin from cellulose and hemicellulose, several types of technical lignin...... of the range of available technical lignins. In this work, catalytic conversion of different types of lignin using an alumina supported NiMo catalyst (provided by Haldor Topsøe A/S) is conducted in ethanol at 310 ˚C with initial hydrogen pressure of 25 barg. The reaction time was set to 3 hours. Proton......, attributed as ‘bio-oil’. GC-MS-FID analysis was used for identification and quantification of the bio-oil and ethanol rich light fraction. The molecular weight of the oil fraction was determined by size exclusion chromatography (SEC). Elemental analysis (Eurovector EuroEA3000) was conducted for measuring...

  15. Effect of lignin content on a GH11 endoxylanase acting on glucuronoarabinoxylan-lignin nanocomposites.

    Science.gov (United States)

    Boukari, Imen; Rémond, Caroline; O'Donohue, Michael; Chabbert, Brigitte

    2012-06-20

    The effects of lignin content on the activity and action pattern of GH11 endoxylanase from Thermobacillus xylanilyticus were investigated using in vitro reconstituted non-covalent glucuronoarabinoxylan-model lignin (GAX-DHP) nanocomposites. Four types of nanocomposites were prepared, each displaying different lignin contents. Variations in the DHP (model lignin) polymerization process were induced by increasing the coniferyl alcohol concentration. Examination of the morphology of the nanocomposites revealed globular particles enrobed in a matrix. The size of these particles increased in line with the lignin concentration. Physicochemical characterization of the in vitro reconstituted GAX-DHPs strongly suggested that increased particle size is directly related to the solubility and reactivity of coniferyl alcohol, as reflected by changes in the amount of β-O-4 linkages. Evaluation of the impact of the GH11 endoxylanase on the GAX-DHP nanocomposites revealed a negative correlation between the proportion and organization patterns of DHP in the nanocomposites and enzyme activity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Reactivity of lignin and lignin models towards UV-assisted peroxide

    International Nuclear Information System (INIS)

    Sun, Y.P.; Wallis, A.F.A.; Nguyen, K.L.

    1997-01-01

    The comparative reactivities of a series of guaiacyl and syringyl lignin model compounds and their methylated analogues towards alkaline peroxide and UV-alkaline peroxide were investigated. The overall reaction was followed by monitoring the reduction of the substrate as a function of time, and in every case, the reaction showed pseudo-first-order kinetics. The reaction rates of most lignin models having identical sidechains with alkaline peroxide and with UV-alkaline peroxide were in the order syringyl guaiacyl 3,4,5-trimethoxyphenyl veratryl. Thus phenols react faster than their methyl ethers, and an extra ortho methoxyl group promotes the reaction. Lignin models possessing electron-donating sidechains had generally higher reaction rates than those with electron-withdrawing sidechains. The reaction rates of the series of benzoic acids were 2-4 times higher at pH 11 than at pH 5. UV-peroxide degradation of a eucalypt kraft lignin was faster than that of a pine kraft lignin, and degradation was 1.4-1.6 times faster at pH 11 than at pH 5. The data are consistent with the formation of higher amounts of reactive radicals under alkaline conditions, and aromatic rings with greater electronegativities promoting reactions with the radicals

  17. Liquefaction of Biorefinery Lignin for Fuel Production

    DEFF Research Database (Denmark)

    Jensen, Anders

    at higher loadings. The effect of increased reaction time was found to be beneficial for oil yields but also caused an increase in solvent consumption and so there is a trade-off where a compromise has to be found in the event of an up scaled reaction. The reactions that cause solvent consumption during......Lignocellulosic biorefineries can be an important piece of the puzzle in fighting climate change. Present, biorefineries that produce ethanol from lignocellulose are challenged in working on market terms as the two product streams ethanol and lignin are low value products. The aim of this project...... has been to increase the value of the lignin stream. Recent regulations on shipping exhaust gasses in coastal waters dictate lower sulfur emissions which require ships to use low sulfur fuels for propulsion. This opens or expands a very large market for low sulfur fuels because a shift from...

  18. Lignin- and Hemicellulose-derived Biomass Recalcitrance

    DEFF Research Database (Denmark)

    Deralia, Parveen Kumar

    technology bringing the multitude of chemical and physical changes, which govern the level of biomass recalcitrance. The lignocellulosic biomasses in question are wheat straw and poplar and the hydrothermal pretreatment is used as pretreatment technology. The 2D HSQC NMR and wet chemistry chemical...... degree to the biomass surface, giving a proportional increase in the specific surface area opposite to wheat straw, which has a marked increase in the specific surface area. The distinctly different chemistry of lignin and hemicellulose and different lignin migration and reorganization appear...... to be correlative, helping explain differences in enzymatic saccharification performance across the pretreatment severities and between two biomasses. The main contribution of this work to the current state-of-the-art in the field is the revelation of distinct behaviors of generation of different repolymerized...

  19. Metabolic and functional diversity of saponins, biosynthetic intermediates and semi-synthetic derivatives

    Science.gov (United States)

    Moses, Tessa; Papadopoulou, Kalliope K.

    2014-01-01

    Saponins are widely distributed plant natural products with vast structural and functional diversity. They are typically composed of a hydrophobic aglycone, which is extensively decorated with functional groups prior to the addition of hydrophilic sugar moieties, to result in surface-active amphipathic compounds. The saponins are broadly classified as triterpenoids, steroids or steroidal glycoalkaloids, based on the aglycone structure from which they are derived. The saponins and their biosynthetic intermediates display a variety of biological activities of interest to the pharmaceutical, cosmetic and food sectors. Although their relevance in industrial applications has long been recognized, their role in plants is underexplored. Recent research on modulating native pathway flux in saponin biosynthesis has demonstrated the roles of saponins and their biosynthetic intermediates in plant growth and development. Here, we review the literature on the effects of these molecules on plant physiology, which collectively implicate them in plant primary processes. The industrial uses and potential of saponins are discussed with respect to structure and activity, highlighting the undoubted value of these molecules as therapeutics. PMID:25286183

  20. Impact of Different Lignin Fractions on Saccharification Efficiency in Diverse Species of the Bioenergy Crop Miscanthus

    NARCIS (Netherlands)

    Weijde, van der Tim; Torres Salvador, Andres Francisco; Dolstra, Oene; Dechesne, Annemarie; Visser, Richard G.F.; Trindade, Luisa M.

    2016-01-01

    Lignin is a key factor limiting saccharification of lignocellulosic feedstocks. In this comparative study, various lignin methods—including acetyl bromide lignin (ABL), acid detergent lignin (ADL), Klason lignin (KL), and modified ADL and KL determination methods—were evaluated for their

  1. The preliminary research for biosynthetic engineering by radiation fusion technology

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Chang Hyun; Jung, U Hee; Park, Hae Ran [KAERI, Daejeon (Korea, Republic of)

    2012-01-15

    The purpose of this project is to elucidate the solution to the production of bioactive substance using biotransformation process from core technology of biosynthetic engineering by radiation fusion technology. And, this strategy will provide core technology for development of drugs as new concept and category. Research scopes and contents of project include 1) The development of mutant for biosynthetic engineering by radiation fusion technology 2) The development of host for biosynthetic engineering by radiation fusion technology 3) The preliminary study for biosynthetic engineering of isoflavone by radiation fusion technology. The results are as follows. Isoflavone compounds(daidzein, hydroxylated isoflavone) were analyzed by GC-MS. The study of radiation doses and p-NCA high-throughput screening for mutant development were elucidated. And, it was carried out the study of radiation doses for host development. Furthermore, the study of redox partner and construction of recombinant strain for region-specific hydroxylation(P450, redox partner). In addition, the biological effect of 6,7,4'-trihydroxyisoflavone as an anti-obesity agent was elucidated in this study.

  2. Lignin Valorization using Heterogenous Catalytic Oxidation

    DEFF Research Database (Denmark)

    Melián Rodríguez, Mayra; Shunmugavel, Saravanamurugan; Kegnæs, Søren

    The research interests in biomass conversion to fuels and chemicals has increased significantly in the last decade in view of current problems such as global warming, high oil prices, food crisis and other geopolitical scenarios. Many different reactions and processes to convert biomass into high...... of the reaction conditions 4. Here, we therefore present an overview of the recent research about conversion of some lignin model compounds using heterogeneous catalysis in oxidation reactions....

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

    Science.gov (United States)

    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. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Chapter 8: Pyrolysis Mechanisms of Lignin Model Compounds Using a Heated Micro-Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Robichaud, David J.; Nimlos, Mark R.; Ellison, G. Barney

    2015-10-03

    Lignin is an important component of biomass, and the decomposition of its thermal deconstruction products is important in pyrolysis and gasification. In this chapter, we investigate the unimolecular pyrolysis chemistry through the use of singly and doubly substituted benzene molecules that are model compounds representative of lignin and its primary pyrolysis products. These model compounds are decomposed in a heated micro-reactor, and the products, including radicals and unstable intermediates, are measured using photoionization mass spectrometry and matrix isolation infrared spectroscopy. We show that the unimolecular chemistry can yield insight into the initial decomposition of these species. At pyrolysis and gasification severities, singly substituted benzenes typically undergo bond scission and elimination reactions to form radicals. Some require radical-driven chain reactions. For doubly substituted benzenes, proximity effects of the substituents can change the reaction pathways.

  5. Radiotracer experiments on lignin reactions, 2

    International Nuclear Information System (INIS)

    Terashima, Noritsugu; Araki, Hiroshi; Suganuma, Nobuo.

    1977-01-01

    The behavior of the specific carbon atoms of lignin during the cooking process was studied. Pine wood meal containing the protolignin labelled with 14-C was prepared, and treated under sulfate cooking conditions. The incorporation and distribution of radioactivity were traced in three fractions separated from the black liquor according to their solubilities and molecular weights. The gamma position carbon at the end of side chain of phenylpropane unit in lignin was eliminated easily from the high molecular weight portion in considerable extent during the cooking process, and a part of the eliminated carbon condenses again with the aromatic ring. However, a large portion of the eliminated gamma-carbon was found in the low molecular fraction of water soluble part of the black liquor. The radioactivity of alpha-carbons in the side chains adjacent to aromatic rings was found to be distributed in three fractions similarly to that of beta-carbons, except that the incorporation of radioactivity of alpha-carbons was slightly low in high molecular fraction, and slightly high in low molecular water soluble fraction as compared with that of beta-carbons and aromatic ring carbons. The number of residual carbon atoms per one monomer unit in high molecular kraft lignin was calculated from the specific incorporation ratio of radioactivity. The carbon skelton was estimated and the molecular formula was given by the elementary analysis and molecular weight determination. (Iwakiri, K.)

  6. The role of phenylpropanoid pathway metabolites in resistance of sorghum to pathogens

    Science.gov (United States)

    Sorghum is being developed for diverse uses, including for bioenergy and food. In order to increase efficiency of ethanol production from plant materials, sorghum lines with reduced lignin were developed by incorporating two mutations in lignin biosynthesis pathway genes: brown midrib (bmr) 6 and bm...

  7. Noncatalytic Direct Liquefaction of Biorefinery Lignin by Ethanol

    DEFF Research Database (Denmark)

    Nielsen, Joachim Bachmann; Jensen, Anders; Madsen, Line Riis

    2017-01-01

    There is a growing interest in lignin valorization to biofuels and chemicals. Here, we propose a novel and simple noncatalytic process to directly liquefy lignin rich solid residual from second generation bioethanol production by solvolysis with ethanol. Through an extensive parameter study...... in batch autoclaves assessing the effects of varying reaction temperature, reaction time, and solvent:lignin ratio, it is shown that hydrothermally pretreated enzymatic hydrolysis lignin solvolysis in supercritical ethanol can produce a heptane soluble bio-oil without the need for exhaustive deoxygenation....... The process does not require addition of catalyst or a reducing agent such as hydrogen. The process is advantageously carried out with a low reaction period ((ethanol:lignin (w/w) ratio of 2:1) which is a previously unexplored domain for lignin...

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

    Science.gov (United States)

    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. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Biodegradation of lignin by Shiitake Lentinus edodes (berk. ) sing

    Energy Technology Data Exchange (ETDEWEB)

    Oki, T.; Watanabe, H.; Ishikawa, H.

    1981-01-01

    Each strain of L. edodes destroyed all of the structural components of wood (Fagus crenata) at almost the same rate during the loss of approximately 30% of the total weight of wood. The activities of the extracellular enzymes, i.e. peroxidase, laccase, and polyphenol oxidase, in the wood powder and lignin-containing cultures increased during the early period of mycelial growth, and then declined rapidly, while the activity of Beta-glucosidase increased gradually throughout the growth period. Functional group analysis, nitrobenzene oxidation, and spectroscopic characterization showed that dioxane lignin from F. crenata degraded by L. edodes or in crude enzyme solution isolated from wood-containing culture had a higher content of carboxyl groups than the sound dioxane lignin, whereas the content of methoxyl group was lower in the degraded dioxane lignin than in sound dioxane lignin. The building units of dioxane lignin, which yield aromatic aldehydes on nitrobenzene oxidation, were attacked preferentially by L. edodes under the above conditions.

  10. Early Phenylpropanoid Biosynthetic Steps in Cannabis sativa: Link between Genes and Metabolites

    Directory of Open Access Journals (Sweden)

    Immacolata Coraggio

    2013-06-01

    Full Text Available Phenylalanine ammonia-lyase (PAL, Cinnamic acid 4-hydroxylase (C4H and 4-Coumarate: CoA ligase (4CL catalyze the first three steps of the general phenylpropanoid pathway whereas chalcone synthase (CHS catalyzes the first specific step towards flavonoids production. This class of specialized metabolites has a wide range of biological functions in plant development and defence and a broad spectrum of therapeutic activities for human health. In this study, we report the isolation of hemp PAL and 4CL cDNA and genomic clones. Through in silico analysis of their deduced amino acid sequences, more than an 80% identity with homologues genes of other plants was shown and phylogenetic relationships were highlighted. Quantitative expression analysis of the four above mentioned genes, PAL and 4CL enzymatic activities, lignin content and NMR metabolite fingerprinting in different Cannabis sativa tissues were evaluated. Furthermore, the use of different substrates to assay PAL and 4CL enzymatic activities indicated that different isoforms were active in different tissues. The diversity in secondary metabolites content observed in leaves (mainly flavonoids and roots (mainly lignin was discussed in relation to gene expression and enzymatic activities data.

  11. Early phenylpropanoid biosynthetic steps in Cannabis sativa: link between genes and metabolites.

    Science.gov (United States)

    Docimo, Teresa; Consonni, Roberto; Coraggio, Immacolata; Mattana, Monica

    2013-06-28

    Phenylalanine ammonia-lyase (PAL), Cinnamic acid 4-hydroxylase (C4H) and 4-Coumarate: CoA ligase (4CL) catalyze the first three steps of the general phenylpropanoid pathway whereas chalcone synthase (CHS) catalyzes the first specific step towards flavonoids production. This class of specialized metabolites has a wide range of biological functions in plant development and defence and a broad spectrum of therapeutic activities for human health. In this study, we report the isolation of hemp PAL and 4CL cDNA and genomic clones. Through in silico analysis of their deduced amino acid sequences, more than an 80% identity with homologues genes of other plants was shown and phylogenetic relationships were highlighted. Quantitative expression analysis of the four above mentioned genes, PAL and 4CL enzymatic activities, lignin content and NMR metabolite fingerprinting in different Cannabis sativa tissues were evaluated. Furthermore, the use of different substrates to assay PAL and 4CL enzymatic activities indicated that different isoforms were active in different tissues. The diversity in secondary metabolites content observed in leaves (mainly flavonoids) and roots (mainly lignin) was discussed in relation to gene expression and enzymatic activities data.

  12. Genome mining of the sordarin biosynthetic gene cluster from Sordaria araneosa Cain ATCC 36386: characterization of cycloaraneosene synthase and GDP-6-deoxyaltrose transferase.

    Science.gov (United States)

    Kudo, Fumitaka; Matsuura, Yasunori; Hayashi, Takaaki; Fukushima, Masayuki; Eguchi, Tadashi

    2016-07-01

    Sordarin is a glycoside antibiotic with a unique tetracyclic diterpene aglycone structure called sordaricin. To understand its intriguing biosynthetic pathway that may include a Diels-Alder-type [4+2]cycloaddition, genome mining of the gene cluster from the draft genome sequence of the producer strain, Sordaria araneosa Cain ATCC 36386, was carried out. A contiguous 67 kb gene cluster consisting of 20 open reading frames encoding a putative diterpene cyclase, a glycosyltransferase, a type I polyketide synthase, and six cytochrome P450 monooxygenases were identified. In vitro enzymatic analysis of the putative diterpene cyclase SdnA showed that it catalyzes the transformation of geranylgeranyl diphosphate to cycloaraneosene, a known biosynthetic intermediate of sordarin. Furthermore, a putative glycosyltransferase SdnJ was found to catalyze the glycosylation of sordaricin in the presence of GDP-6-deoxy-d-altrose to give 4'-O-demethylsordarin. These results suggest that the identified sdn gene cluster is responsible for the biosynthesis of sordarin. Based on the isolated potential biosynthetic intermediates and bioinformatics analysis, a plausible biosynthetic pathway for sordarin is proposed.

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

    Directory of Open Access Journals (Sweden)

    Wei Fang

    Full Text Available 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

  14. Lignin transformations and reactivity upon ozonation in aqueous media

    Science.gov (United States)

    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.

  15. Improved lignin polyurethane properties with Lewis acid treatment.

    Science.gov (United States)

    Chung, Hoyong; Washburn, Newell R

    2012-06-27

    Chemical modification strategies to improve the mechanical properties of lignin-based polyurethanes are presented. We hypothesized that treatment of lignin with Lewis acids would increase the concentration of hydroxyl groups available to react with diisocyanate monomers. Under the conditions used, hydrogen bromide-catalyzed modification resulted in a 28% increase in hydroxyl group content. Associated increases in hydrophilicity of solvent-cast thin films were also recorded as evidenced by decreases in water contact angle. Polyurethanes were then prepared by first preparing a prepolymer based on mixtures of toluene-2,4-diisocyanate (TDI) and unmodified or modified lignin, then polymerization was completed through addition of polyethylene glycol (PEG), resulting in mass ratios of TDI:lignin:PEG of 43:17:40 in the compositions investigated here. The mixture of TDI and unmodified lignin resulted in a lignin powder at the bottom of the liquid, suggesting it did not react directly with TDI. However, a homogeneous solution resulted when TDI and the hydrogen bromide-treated lignin were mixed, suggesting demethylation indeed increased reactivity and resulted in better integration of lignin into the urethane network. Significant improvements in mechanical properties of modified lignin polyurethanes were observed, with a 6.5-fold increase in modulus, which were attributed to better integration of the modified lignin into the covalent polymer network due to the higher concentration of hydroxyl groups. This research indicates that chemical modification strategies can lead to significant improvements in the properties of lignin-based polymeric materials using a higher fraction of an inexpensive lignin monomer from renewable resources and a lower fraction an expensive, petroleum-derived isocyanate monomer to achieve the required material properties.

  16. Isolation and Characterization of Gramineae and Fabaceae Soda Lignins.

    Science.gov (United States)

    Domínguez-Robles, Juan; Sánchez, Rafael; Espinosa, Eduardo; Savy, Davide; Mazzei, Pierluigi; Piccolo, Alessandro; Rodríguez, Alejandro

    2017-02-04

    Some agricultural residues such as wheat or barley straw, as well as certain fast-growing plants like Leucaena leucocephala and Chamaecytisus proliferus , could be used as raw materials for the paper industry as an alternative to traditional plants (eucalyptus, pine, etc.). In the present study, four types of lignin obtained from the spent liquors produced by the pulping processes using the abovementioned feedstocks were isolated and characterized. Lignin samples were acquired through an acid precipitation from these spent liquors. The characterization of the precipitated lignin samples were performed using a Fourier transform infrared spectroscopy (FT-IR) and both liquid- and solid-state nuclear magnetic resonance spectroscopy (NMR) to analyse the chemical structure, and thermogravimetric analysis (TGA) for determining the thermal properties. Additionally, chemical composition of lignin fractions was also measured. Even though they were of different botanical origin, all the studied samples except for wheat straw lignin had a similar chemical composition and thermal behaviour, and identical chemical structure. Wheat straw lignin showed a greater amount of Klason lignin and lower carbohydrate content. Furthermore, this lignin sample showed a higher thermal stability and significantly different cross-peak patterns in the 2D-NMR experiments. The molecular structures corresponding to p -coumarate (PCA), ferulate (FA) and cinnamyl aldehyde end-groups (J) were only detected in wheat isolated lignin.

  17. Dissolution of lignin in green urea aqueous solution

    Science.gov (United States)

    Wang, Jingyu; Li, Ying; Qiu, Xueqing; Liu, Di; Yang, Dongjie; Liu, Weifeng; Qian, Yong

    2017-12-01

    The dissolution problem is the main obstacle for the value-added modification and depolymerization of industrial lignin. Here, a green urea aqueous solution for complete dissolution of various lignin is presented and the dissolution mechanism is analyzed by AFM, DLS and NMR. The results show that the molecular interaction of lignin decreases from 32.3 mN/m in pure water to 11.3 mN/m in urea aqueous solution. The immobility of 1H NMR spectra and the shift of 17O NMR spectra of urea in different lignin/urea solutions indicate that the oxygen of carbonyl in urea and the hydrogen of hydroxyl in lignin form new hydrogen bonds and break the original hydrogen bonds among lignin molecules. The shift of 1H NMR spectra of lignin and the decrease of interactions in model compound polystyrene indicate that urea also breaks the π-π interactions between aromatic rings of lignin. Lignin dissolved in urea aqueous has good antioxidant activity and it can scavenge at least 63% free radicals in 16 min.

  18. Valorization of lignin from biorefineries for fuels and chemicals

    DEFF Research Database (Denmark)

    Nielsen, Joachim Bachmann

    Direct lignin liquefaction is a promising process for lignin valorization in which ligninis treated in a solvent at elevated temperature and pressure. Liquefaction of sulfur freelignin obtained as a waste product from 2nd generation bio-ethanol production canprovide a sulfur free bio-oil which may...... substitute fossil fuel.In this Ph.D. study the direct liquefaction of a biorefinery lignin (hydrothermallypretreated enzymatic hydrolysis lignin) is explored. The goal is to provide a bio-crude which can substitute marine diesel as the engines found aboard large ships are adapted to more crude fuels. A novel...

  19. Kraft Lignin Depolymerization in an Ionic Liquid without a Catalyst

    Directory of Open Access Journals (Sweden)

    Amadou Diop

    2015-06-01

    Full Text Available In this paper, the depolymerization of lignin was successfully achieved by the thermal treatment of kraft lignin in butyl-1,8-diazabicyclo[5.4.0]undec-7-enium chloride ([DBUC4+][Cl-] without a catalyst. The thermal treatment experiments were performed in an oven at 150, 200, and 250 °C for 1 h. The changes in kraft lignin structure over the course of depolymerization were characterized by gel permeation chromatography (GPC, Fourier transform infrared (FTIR spectroscopy, and 1H / 31P NMR analyses. GPC chromatograms indicated that the retention time of the original kraft lignin had shifted toward higher values after the thermal treatment, which indicated lignin depolymerization. The average molecular weight of the lignin obtained after 1 h reaction time decreased by 23, 70, and 58 wt% for the treatment at 150, 200, and 250 °C, respectively. FTIR spectra indicated the cleavage of β-O-4 bonds of kraft lignin. The 1H NMR spectra showed demethylation of all treated kraft lignins. Moreover, the 31P NMR analysis demonstrated that the demethylation phenomenon of the treated kraft lignin contributed to the formation of catechol groups.

  20. Preparation and Characterization of Modified Soda Lignin with Polyethylene Glycol

    Directory of Open Access Journals (Sweden)

    Fangda Zhang

    2016-10-01

    Full Text Available Soda lignin does not have thermal flowing characteristics and it is impossible for it to be further thermally molded. To achieve the fusibility of soda lignin for fiber preparation by melt-spinning, an effective method for soda lignin modification was conducted by cooking it with polyethylene glycol (PEG 400 at various ratios. The higher the ratio of PEG that was used, the more PEG molecular chains were grafted at the alpha carbon of the soda lignin through ether bonds, resulting in lower thermal transition temperatures and more excellent fusibility. The modified soda lignin with a weight ratio of lignin to PEG of 1:4 exhibited a relative thermal stability of molten viscosity at selected temperatures. Thereafter, the resultant fusible soda lignin was successfully melt-spun into filaments with an average diameter of 33 ± 5 μm, which is smaller than that of some industrial lignins. Accordingly, it is possible to utilize soda lignin to produce fibrous carbonaceous materials.

  1. Isolation and Characterization of Gramineae and Fabaceae Soda Lignins

    Science.gov (United States)

    Domínguez-Robles, Juan; Sánchez, Rafael; Espinosa, Eduardo; Savy, Davide; Mazzei, Pierluigi; Piccolo, Alessandro; Rodríguez, Alejandro

    2017-01-01

    Some agricultural residues such as wheat or barley straw, as well as certain fast-growing plants like Leucaena leucocephala and Chamaecytisus proliferus, could be used as raw materials for the paper industry as an alternative to traditional plants (eucalyptus, pine, etc.). In the present study, four types of lignin obtained from the spent liquors produced by the pulping processes using the abovementioned feedstocks were isolated and characterized. Lignin samples were acquired through an acid precipitation from these spent liquors. The characterization of the precipitated lignin samples were performed using a Fourier transform infrared spectroscopy (FT-IR) and both liquid- and solid-state nuclear magnetic resonance spectroscopy (NMR) to analyse the chemical structure, and thermogravimetric analysis (TGA) for determining the thermal properties. Additionally, chemical composition of lignin fractions was also measured. Even though they were of different botanical origin, all the studied samples except for wheat straw lignin had a similar chemical composition and thermal behaviour, and identical chemical structure. Wheat straw lignin showed a greater amount of Klason lignin and lower carbohydrate content. Furthermore, this lignin sample showed a higher thermal stability and significantly different cross-peak patterns in the 2D-NMR experiments. The molecular structures corresponding to p-coumarate (PCA), ferulate (FA) and cinnamyl aldehyde end-groups (J) were only detected in wheat isolated lignin. PMID:28165411

  2. Isolation and Characterization of Gramineae and Fabaceae Soda Lignins

    Directory of Open Access Journals (Sweden)

    Juan Domínguez-Robles

    2017-02-01

    Full Text Available Some agricultural residues such as wheat or barley straw, as well as certain fast-growing plants like Leucaena leucocephala and Chamaecytisus proliferus, could be used as raw materials for the paper industry as an alternative to traditional plants (eucalyptus, pine, etc.. In the present study, four types of lignin obtained from the spent liquors produced by the pulping processes using the abovementioned feedstocks were isolated and characterized. Lignin samples were acquired through an acid precipitation from these spent liquors. The characterization of the precipitated lignin samples were performed using a Fourier transform infrared spectroscopy (FT-IR and both liquid- and solid-state nuclear magnetic resonance spectroscopy (NMR to analyse the chemical structure, and thermogravimetric analysis (TGA for determining the thermal properties. Additionally, chemical composition of lignin fractions was also measured. Even though they were of different botanical origin, all the studied samples except for wheat straw lignin had a similar chemical composition and thermal behaviour, and identical chemical structure. Wheat straw lignin showed a greater amount of Klason lignin and lower carbohydrate content. Furthermore, this lignin sample showed a higher thermal stability and significantly different cross-peak patterns in the 2D-NMR experiments. The molecular structures corresponding to p-coumarate (PCA, ferulate (FA and cinnamyl aldehyde end-groups (J were only detected in wheat isolated lignin.

  3. Progress in lignin hydrogels and nanocomposites for water purification

    DEFF Research Database (Denmark)

    Tamulevicius, Sigitas; Thakur, Sourbh; Govender, Penny P.

    2017-01-01

    -based hydrogels have shown excellent performance for removal of various pollutants from water. The adsorption properties of lignin based hydrogels can further be improved by using a combination of nanomaterials and lignin that results in promising hydrogel nanocomposites. In nature, the most abundant structures...... are formed by the combination of lignin, cellulose and hemicelluloses. In this article, we have attempted to comprehensively review the research work carried out in the direction of usage of lignin-based hydrogel for removal of toxic pollutants including metal ions and dyes....

  4. Effective Release of Lignin Fragments from Lignocellulose by Lewis Acid Metal Triflates in the Lignin-First Approach.

    Science.gov (United States)

    Huang, Xiaoming; Zhu, Jiadong; Korányi, Tamás I; Boot, Michael D; Hensen, Emiel J M

    2016-12-08

    Adding value to lignin, the most complex and recalcitrant fraction in lignocellulosic biomass, is highly relevant to costefficient operation of biorefineries. We report the use of homogeneous metal triflates to rapidly release lignin from biomass. Combined with metal-catalyzed hydrogenolysis, the process separates woody biomass into few lignin-derived alkylmethoxyphenols and cellulose under mild conditions. Model compound studies show the unique catalytic properties of metal triflates in cleaving lignin-carbohydrate interlinkages. The lignin fragments can then be disassembled by hydrogenolysis. The tandem process is flexible and allows obtaining good aromatic monomer yields from different woods (36-48 wt %, lignin base). The cellulose-rich residue is an ideal feedstock for established biorefining processes. The highly productive strategy is characterized by short reaction times, low metal triflate catalyst requirement, and leaving cellulose largely untouched. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. antiSMASH 3.0-a comprehensive resource for the genome mining of biosynthetic gene clusters.

    Science.gov (United States)

    Weber, Tilmann; Blin, Kai; Duddela, Srikanth; Krug, Daniel; Kim, Hyun Uk; Bruccoleri, Robert; Lee, Sang Yup; Fischbach, Michael A; Müller, Rolf; Wohlleben, Wolfgang; Breitling, Rainer; Takano, Eriko; Medema, Marnix H

    2015-07-01

    Microbial secondary metabolism constitutes a rich source of antibiotics, chemotherapeutics, insecticides and other high-value chemicals. Genome mining of gene clusters that encode the biosynthetic pathways for these metabolites has become a key methodology for novel compound discovery. In 2011, we introduced antiSMASH, a web server and stand-alone tool for the automatic genomic identification and analysis of biosynthetic gene clusters, available at http://antismash.secondarymetabolites.org. Here, we present version 3.0 of antiSMASH, which has undergone major improvements. A full integration of the recently published ClusterFinder algorithm now allows using this probabilistic algorithm to detect putative gene clusters of unknown types. Also, a new dereplication variant of the ClusterBlast module now identifies similarities of identified clusters to any of 1172 clusters with known end products. At the enzyme level, active sites of key biosynthetic enzymes are now pinpointed through a curated pattern-matching procedure and Enzyme Commission numbers are assigned to functionally classify all enzyme-coding genes. Additionally, chemical structure prediction has been improved by incorporating polyketide reduction states. Finally, in order for users to be able to organize and analyze multiple antiSMASH outputs in a private setting, a new XML output module allows offline editing of antiSMASH annotations within the Geneious software. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  6. Recent advances in biosynthetic modeling of nitric oxide reductases and insights gained from nuclear resonance vibrational and other spectroscopic studies

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Saumen; Reed, Julian; Sage, Timothy; Branagan, Nicole C.; Petrik, Igor D.; Miner, Kyle D.; Hu, Michael Y.; Zhao, Jiyong; Alp, E. Ercan; Lu, Yi

    2015-10-05

    This Forum Article focuses on recent advances in structural and spectroscopic studies of biosynthetic models of nitric oxide reductases (NORs). NORs are complex metalloenzymes found in the denitrification pathway of Earth's nitrogen cycle where they catalyze the proton-dependent twoelectron reduction of nitric oxide (NO) to nitrous oxide (N2O). While much progress has been made in biochemical and biophysical studies of native NORs and their variants, a. clear mechanistic understanding of this important metalloenzyme related to its function is still elusive. We report herein UV vis and nuclear resonance vibrational spectroscopy (NRVS) studies of mononitrosylated intermediates of the NOR reaction of a biosynthetic model. The ability to selectively substitute metals at either heme or nonheme metal sites allows the introduction of independent 57Fe probe atoms at either site, as well as allowing the preparation of analogues of stable reaction intermediates by replacing either metal with a redox inactive metal. Together with previous structural and spectroscopic results, we summarize insights gained from studying these biosynthetic models toward understanding structural features responsible for the NOR activity and its mechanism. As a result, the outlook on NOR modeling is also discussed, with an emphasis on the design of models capable of catalytic turnovers designed based on close mimics of the secondary coordination sphere of native NORs.

  7. New insights into the structure and composition of technical lignins : A comparative characterisation study

    NARCIS (Netherlands)

    Constant, Sandra|info:eu-repo/dai/nl/374650519; Wienk, Hans L J|info:eu-repo/dai/nl/203884884; Frissen, Augustinus E.; Peinder, Peter De|info:eu-repo/dai/nl/325810818; Boelens, Rolf|info:eu-repo/dai/nl/070151407; Van Es, Daan S.; Grisel, Ruud J H; Weckhuysen, Bert M.|info:eu-repo/dai/nl/285484397; Huijgen, Wouter J J; Gosselink, Richard J A; Bruijnincx, Pieter C A|info:eu-repo/dai/nl/33799529X

    2016-01-01

    Detailed insight into the structure and composition of industrial (technical) lignins is needed to devise efficient thermal, bio- or chemocatalytic valorisation strategies. Six such technical lignins covering three main industrial pulping methods (Indulin AT Kraft, Protobind 1000 soda lignin and

  8. New insights into the structure and composition of technical lignins: a comparative characterisation study

    NARCIS (Netherlands)

    Constant, Sandra; Wienk, Hans L.J.; Frissen, A.E.; Peinder, de Peter; Boelens, Rolf; Es, van D.S.; Grisel, Ruud J.H.; Weckhuysen, Bert M.; Huijgen, W.J.J.; Gosselink, R.J.A.; Bruijnincx, Pieter C.A.

    2016-01-01

    Detailed insight into the structure and composition of industrial (technical) lignins is needed to devise efficient thermal, bio- or chemocatalytic valorisation strategies. Six such technical lignins covering three main industrial pulping methods (Indulin AT Kraft, Protobind 1000 soda lignin and

  9. Biosynthetic origin of the isoprene units in chromenes of Piper aduncum (Piperaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Leite, Ana C.; Lopes, Adriana A.; Bolzani, Vanderlan da S.; Furlan, Maysa [UNESP, Araraquara, SP (Brazil). Inst. de Quimica]. E-mail: maysaf@iq.unesp.br; Kato, Massuo J. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Quimica

    2007-07-01

    Metabolic studies involving the incorporation of [1-{sup 13}C]-D-glucose into intact leaves of Piper aduncum (Piperaceae) have indicated that both the mevalonate (MVA) and the pyruvate-triose (MEP) non-mevalonate pathways are implicated in the biosynthesis of isoprene moieties present in methyl 2,2-dimethyl-2H-1-chromene-6-carboxylate (1) and methyl 2,2-dimethyl-8-(3'-methyl- 2'-butenyl)-2H-1-chromene-6-carboxylate (2). The pattern of incorporation of label from [1- {sup 13}C]-D-glucose into these chromenes was determined by quantitative {sup 13}C NMR spectroscopy. The results confirmed that biosynthetic compartment of 1 and 2 could either be the plastid and/ or the cytosol or, possibly, an additional compartment such as the plastid inter-membrane space. (author)

  10. Biosynthetic origin of the isoprene units in chromenes of Piper aduncum (Piperaceae)

    International Nuclear Information System (INIS)

    Leite, Ana C.; Lopes, Adriana A.; Bolzani, Vanderlan da S.; Furlan, Maysa; Kato, Massuo J.

    2007-01-01

    Metabolic studies involving the incorporation of [1- 13 C]-D-glucose into intact leaves of Piper aduncum (Piperaceae) have indicated that both the mevalonate (MVA) and the pyruvate-triose (MEP) non-mevalonate pathways are implicated in the biosynthesis of isoprene moieties present in methyl 2,2-dimethyl-2H-1-chromene-6-carboxylate (1) and methyl 2,2-dimethyl-8-(3'-methyl- 2'-butenyl)-2H-1-chromene-6-carboxylate (2). The pattern of incorporation of label from [1- 13 C]-D-glucose into these chromenes was determined by quantitative 13 C NMR spectroscopy. The results confirmed that biosynthetic compartment of 1 and 2 could either be the plastid and/ or the cytosol or, possibly, an additional compartment such as the plastid inter-membrane space. (author)

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

    Science.gov (United States)

    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. © 2012 The Authors. Plant Biotechnology Journal © 2012 Society for Experimental Biology, Association of Applied

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

    OpenAIRE

    Eudes, Aymerick; George, Anthe; Mukerjee, Purba; Kim, J.S.; Pollet, B.; Bnke, P.I.; Persil Çetinkol, Özgül

    2012-01-01

    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 Arab...

  13. Fast Pyrolysis of Four Lignins from Different Isolation Processes Using Py-GC/MS

    OpenAIRE

    Lin, Xiaona; Sui, Shujuan; Tan, Shun; Pittman, Charles; Sun, Jianping; Zhang, Zhijun

    2015-01-01

    Pyrolysis is a promising approach that is being investigated to convert lignin into higher value products including biofuels and phenolic chemicals. In this study, fast pyrolysis of four types of lignin, including milled Amur linden wood lignin (MWL), enzymatic hydrolysis corn stover lignin (EHL), wheat straw alkali lignin (AL) and wheat straw sulfonate lignin (SL), were performed using pyrolysis gas-chromatography/mass spectrometry (Py-GC/MS). Thermogravimetric analysis (TGA) showed that the...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  16. Determining Antifungal Target Sites in the Sterol Pathway of the Yeast Candida and Saccharomyces

    National Research Council Canada - National Science Library

    Bard, Martin

    1998-01-01

    ... as in topical infections which lead to significant losses in work-place productivity. The work reported here seeks to identify new target sites in the sterol biosynthetic pathway against which new antifungal compounds might be developed...

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

    Science.gov (United States)

    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.

  18. Steam gasification of a thermally pretreated high lignin corn stover simultaneous saccharification and fermentation digester residue

    Energy Technology Data Exchange (ETDEWEB)

    Howe, Daniel T.; Taasevigen, Danny; Garcia-Perez, Manuel; McDonald, Armando G.; Li, Guosheng; Wolcott, Michael

    2017-01-01

    Efficient conversion of all components in lignocellulosic biomass is essential to realizing economic feasibility of biorefineries. However, when utilizing biochemical pathways, lignin cannot be fermented. Furthermore, the high lignin and high ash residue resulting from simultaneous saccharification and fermentation (SSF) reactors is difficult to thermochemically process due to feed line plugging and bed agglomeration. In this study a corn stover SSF digester residue was thermally pretreated at 300°C for 22.5 minutes (min) and then gasified in a bubbling fluidized bed gasifier to study the effect of thermal pretreatment on its processing behavior. Untreated, pelletized SSF residue was gasified at the same conditions to establish the baseline processing behavior. Results indicate that the thermal pretreatment process removes a substantial portion of the polar and non-polar extractives, with a resultant increase in the concentration of lignin, cellulose, and ash. Feed line plugging was not observed, although bed agglomeration was occurring at similar rates for both feedstocks, suggesting that overall ash content is the most important factor affecting bed agglomeration. Benzene, phenol, and polyaromatic hydrocarbons in the tar were present at higher concentrations in the treated material, with higher tar loading in the product gas. Total product gas generation is lower for the treated material, although the overall gas composition does not change.

  19. Enzymatic Synthesis of Lignin-Based Concrete Dispersing Agents.

    Science.gov (United States)

    Jankowska, Dagmara; Heck, Tobias; Schubert, Mark; Yerlikaya, Alpaslan; Weymuth, Christophe; Rentsch, Daniel; Schober, Irene; Richter, Michael

    2018-03-15

    Lignin is the most abundant aromatic biopolymer, functioning as an integral component of woody materials. In its unmodified form it shows limited water solubility and is relatively unreactive, so biotechnological lignin valorisation for high-performance applications is greatly underexploited. Lignin can be obtained from the pulp and paper industry as a by-product. To expand its application, a new synthesis route to new dispersing agents for use as concrete additives was developed. The route is based on lignin functionalisation by enzymatic transformation. Screening of lignin-modifying systems resulted in functionalised lignin polymers with improved solubility in aqueous systems. Through grafting of sulfanilic acid or p-aminobenzoic acid by fungal laccases, lignin became soluble in water at pH≤4 or pH≤7, respectively. Products were analysed and evaluated in miniaturised application tests in cement paste and mortar. Their dispersing properties match the performance criteria of commercially available lignosulfonates. The study provides examples of new perspectives for the use of lignin. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. The investigation of wood hydrolysis lignin ability for uranium sorption

    International Nuclear Information System (INIS)

    Rachkova, N.G.; Shuktomova, I.I.; Taskaev, A.I.

    2001-01-01

    The uranium are sorbed in wood hydrolysis lignin efficacious and very strong both in uranyl nitrate solutions and in podsolic soil. It may well be that formation of complexes are possible mechanism of irreversible sorption. The static capacity of lignin are 2.7 mg/g. (author)

  1. The chemical oxidation of lignin found in Sappi Saiccor dissolving ...

    African Journals Online (AJOL)

    Sappi Saiccor (situated in Durban, South Africa) dissolving pulp mill effluent, produced from an acid bisulphite pulping process, uses acacia and eucalyptus hardwoods to produce a unique and different blend of lignin that has not been previously studied. The chemical oxidation of lignin found in Sappi Saiccor's effluent has ...

  2. Structural characterization of lignin from grape stalks (Vitis vinifera L.).

    Science.gov (United States)

    Prozil, Sónia O; Evtuguin, Dmitry V; Silva, Artur M S; Lopes, Luísa P C

    2014-06-18

    The chemical structure of lignin from grape stalks, an abundant waste of winemaking, has been studied. The dioxane lignin was isolated from extractive- and protein-free grape stalks (Vitis vinifera L.) by modified acidolytic procedure and submitted to a structural analysis by wet chemistry (nitrobenzene and permanganate oxidation (PO)) and spectroscopic techniques. The results obtained suggest that grape stalk lignin is an HGS type with molar proportions of p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) units of 3:71:26. Structural analysis by (1)H and (13)C NMR spectroscopy and PO indicates the predominance of β-O-4' structures (39% mol) in grape stalk lignin together with moderate amounts of β-5', β-β, β-1', 5-5', and 4-O-5' structures. NMR studies also revealed that grape lignin should be structurally associated with tannins. The condensation degree of grape stalks lignin is higher than that of conventional wood lignins and lignins from other agricultural residues.

  3. Production of lignin peroxidase by Ganoderma leucidum using solid ...

    African Journals Online (AJOL)

    The main objectives of this study were to optimize the culture conditions for the production of lignin peroxidase by Ganoderma leucidum, economic utilization of waste corn cobs as inducers substrate by pollution free fermentation technology and to optimize the solid state fermentation (SSF) process for lignin peroxidase ...

  4. Effect of periodate on lignin for wood adhesive application

    NARCIS (Netherlands)

    Gosselink, R.J.A.; Dam, van J.E.G.; Jong, de E.; Gellerstedt, G.; Scott, E.L.; Sanders, J.P.M.

    2011-01-01

    Development of eco-friendly binders with no harmful emission during its complete life cycle is of high interest for the wood-based industry. In this paper, a fully renewable binder based on activated lignin and poly-furfuryl alcohol and a partly renewable lignin based phenol-formaldehyde (PF) binder

  5. Metal Triflates for the Production of Aromatics from Lignin

    NARCIS (Netherlands)

    Deuss, Peter J.; Lahive, Ciaran W.; Lancefield, Christopher S.; Westwood, Nicholas J.; Kamer, Paul C. J.; Barta, Katalin; de Vries, Johannes G.

    2016-01-01

    The depolymerization of lignin into valuable aromatic chemicals is one of the key goals towards establishing economically viable biorefineries. In this contribution we present a simple approach for converting lignin to aromatic monomers in high yields under mild reaction conditions. The methodology

  6. Characterisation and application of NovaFiber lignin

    NARCIS (Netherlands)

    Gosselink, R.J.A.; Snijder, M.H.B.; Kranenbarg, A.; Keijsers, E.R.P.; Jong, de E.; Stigsson, L.L.

    2004-01-01

    Sulphur-free lignin coming from a novel alkaline-pulping process called NovaFiber, which has been developed by KIRAM AB, has been characterised and evaluated for potential applications. A Kraft lignin has been used for comparison. Considering the characterisation results of a NovaFiber softwood and

  7. Molecular basis of the evolution of alternative tyrosine biosynthetic routes in plants

    Energy Technology Data Exchange (ETDEWEB)

    Schenck, Craig A.; Holland, Cynthia K.; Schneider, Matthew R.; Men, Yusen; Lee, Soon Goo; Jez, Joseph M.; Maeda , Hiroshi A. (UW); (WU)

    2017-06-26

    L-Tyrosine (Tyr) is essential for protein synthesis and is a precursor of numerous specialized metabolites crucial for plant and human health. Tyr can be synthesized via two alternative routes by different key regulatory TyrA family enzymes, prephenate dehydrogenase (PDH, also known as TyrAp) or arogenate dehydrogenase (ADH, also known as TyrAa), representing a unique divergence of primary metabolic pathways. The molecular foundation underlying the evolution of these alternative Tyr pathways is currently unknown. Here we characterized recently diverged plant PDH and ADH enzymes, obtained the X-ray crystal structure of soybean PDH, and identified a single amino acid residue that defines TyrA substrate specificity and regulation. Structures of mutated PDHs co-crystallized with Tyr indicate that substitutions of Asn222 confer ADH activity and Tyr sensitivity. Reciprocal mutagenesis of the corresponding residue in divergent plant ADHs further introduced PDH activity and relaxed Tyr sensitivity, highlighting the critical role of this residue in TyrA substrate specificity that underlies the evolution of alternative Tyr biosynthetic pathways in plants.

  8. Lignin-based cement fluid loss control additive

    Energy Technology Data Exchange (ETDEWEB)

    Schilling, P.

    1990-05-22

    This patent describes a hydraulic cement slurry composition. It comprises: a hydraulic cement, and the following expressed as parts by weight per 100 parts of the hydraulic cement, water from about 25 to 105 parts, and from abut 0.5 to 2.5 parts of a compound selected from the group consisting of a sulfonated lignin and a sulfomethylated lignin, wherein the lignin has been sequentially crosslinked by reacting the lignin with a member of the group consisting of formaldehyde and epichlorohydrin and alkoxylated with between about 2 to about 6 moles of a compound selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide and a combination thereof per 1000 g of the lignin.

  9. EFFECT OF LIGNIN CONTENT ON ENZYMATIC HYDROLYSIS OF FURFURAL RESIDUES

    Directory of Open Access Journals (Sweden)

    Jianxin Jiang

    2011-02-01

    Full Text Available The enzymatic saccharification of pretreated furfural residues with different lignin content was studied to verify the effect of lignin removal in the hydrolysis process. The results showed that the glucose yield was improved by increasing the lignin removal. A maximum glucose yield of 96.8% was obtained when the residue with a lignin removal of 51.4% was hydrolyzed for 108 h at an enzyme loading of 25 FPU/g cellulose. However, further lignin removal did not increase the hydrolysis. The effect of enzyme loading on the enzymatic hydrolysis was also explored in this work. It was concluded that a high glucose yield of 90% was achieved when the enzyme dosage was reduced from 25 to 15 FPU/g cellulose, which was cost-effective for the sugar and ethanol production. The structures of raw material and delignified samples were further characterized by XRD and scanning electron microscopy (SEM.

  10. Process for conversion of lignin to reformulated hydrocarbon gasoline

    Science.gov (United States)

    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.

  11. Nitroxyl-mediated oxidation of lignin and polycarboxylated products

    Energy Technology Data Exchange (ETDEWEB)

    Stahl, Shannon S.; Rafiee, Mohammad

    2018-02-27

    Methods of selectively modifying lignin, polycarboxylated products thereof, and methods of deriving aromatic compounds therefrom. The methods comprise electrochemically oxidizing lignin using stable nitroxyl radicals to selectively oxidize primary hydroxyls on .beta.-O-4 phenylpropanoid units to corresponding carboxylic acids while leaving the secondary hydroxyls unchanged. The oxidation results in polycarboxylated lignin in the form of a polymeric .beta.-hydroxy acid. The polymeric .beta.-hydroxy acid has a high loading of carboxylic acid and can be isolated in acid form, deprotonated, and/or converted to a salt. The .beta.-hydroxy acid, anion, or salt can also be subjected to acidolysis to generate various aromatic monomers or oligomers. The initial oxidation of lignin to the polycarboxylated form renders the lignin more susceptible to acidolysis and thereby enhances the yield of aromatic monomers and oligomers obtained through acidolysis.

  12. Influence of Reaction Conditions on Lignin Hydrothermal Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Erdocia, Xabier; Prado, Raquel; Corcuera, M. Ángeles; Labidi, Jalel, E-mail: jalel.labidi@ehu.es [Chemical and Environmental Engineering Department, University of the Basque Country, San Seabastian (Spain)

    2014-04-01

    Organosolv lignin, obtained from olive tree pruning under optimized conditions, was subjected to a hydrothermal depolymerization process catalyzed by sodium hydroxide. The depolymerization of lignin was carried out at 300°C using different reaction times (20, 40, 60, 70, 80, 90, and 100 min) in order to study the influence of this parameter on lignin depolymerization. The resulting products (oil and residual lignin) were measured and analyzed by different techniques (GC/MS, high-performance size-exclusion chromatography, and pyrolysis–GC/MS) in order to determine their nature and composition. Coke was also formed, at a lower quantity, uncompetitive repolymerization reactions during the lignin hydrothermal treatment. The maximum oil yield and concentration of monomeric phenolic compounds was obtained after 80 min of reaction time. The highest reaction time studied (100 min) had the worst results with the lowest oil yield and highest coke production.

  13. A cell wall-bound anionic peroxidase, PtrPO21, is involved in lignin polymerization in Populus trichocarpa

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chien-Yuan; Li, Quanzi; Tunlaya-Anukit, Sermsawat; Shi, Rui; Sun, Ying-Hsuan; Wang, Jack P.; Liu, Jie; Loziuk, Philip; Edmunds, Charles W.; Miller, Zachary D.; Peszlen, Ilona; Muddiman, David C.; Sederoff, Ronald R.; Chiang, Vincent L.

    2016-03-11

    Class III peroxidases are members of a large plant-specific sequence-heterogeneous protein family. Several sequence-conserved homologs have been associated with lignin polymerization in Arabidopsis thaliana, Oryza sativa, Nicotiana tabacum, Zinnia elegans, Picea abies, and Pinus sylvestris. In Populus trichocarpa, a model species for studies of wood formation, the peroxidases involved in lignin biosynthesis have not yet been identified. To do this, we retrieved sequences of all PtrPOs from Peroxibase and conducted RNA-seq to identify candidates. Transcripts from 42 PtrPOs were detected in stem differentiating xylem (SDX) and four of them are the most xylem-abundant (PtrPO12, PtrPO21, PtrPO42, and PtrPO64). PtrPO21 shows xylem-specific expression similar to that of genes encoding the monolignol biosynthetic enzymes. Using protein cleavage-isotope dilution mass spectrometry, PtrPO21 is detected only in the cell wall fraction and not in the soluble fraction. Downregulated transgenics of PtrPO21 have a lignin reduction of ~20% with subunit composition (S/G ratio) similar to wild type. The transgenics show a growth reduction and reddish color of stem wood. The modulus of elasticity (MOE) of the stems of the downregulated PtrPO21-line 8 can be reduced to ~60% of wild type. Differentially expressed gene (DEG) analysis of PtrPO21 downregulated transgenics identified a significant overexpression of PtPrx35, suggesting a compensatory effect within the peroxidase family. No significant changes in the expression of the 49 P. trichocarpa laccases (PtrLACs) were observed.

  14. Wood chemistry symposium: from muka to lignin

    Energy Technology Data Exchange (ETDEWEB)

    MacLeod, M.

    1979-01-01

    The Canadian Wood Chemistry Symposium held during September, 1979, is reviewed. The chemical and physical explanations of delignification were debated. Problems of mechanical pulping include insufficient brightness, yellowing, and low strength relative to energy consumption. A session on chemicals, energy, and food from wood began with criteria for a viable project, which included adequate return on investment, modest capital investment requirements, identified pre-existing markets, and favorable thermodynamic balances. The pulp and paper industry should improve its methods of using bark and wood waste in direct combustion (by pre-drying wastes and improving furnace efficiency) rather than supporting oil-from-wood projects, since using a waste for fuel will free fossil fuels for uses in synthetic fibers and thermoplastics. In the area of food, there are modest successes with cellulose fiber additives to bread and snack food and single cell protein (which, though made from wastes, cannot compete with soy protein). However, making monomeric sugars from wood polysaccharides is not an efficient process, and muka, animal feed supplement from foliage, is successful only in Russia. In Canada it cannot compete with agricultural products. Alpha cellulose is a major wood chemical product. Promising uses include cellulose derived thermoplastics and lignosulphonates for secondary oil recovery. Instead of breaking wood polysaccharides and lignin into monomers and then repolymerizing them, it is possible to use the pre-built polymers; such an approach is illustrated by use of lignin in polyurethane foams, adhesives, and coatings.

  15. Characterisation of Authentic Lignin Biorefinery Samples by Fourier Transform Infrared Spectroscopy and Determination of the Chemical Formula for Lignin

    DEFF Research Database (Denmark)

    Le, Duy Michael; Damgaard Nielsen, Anders; Sørensen, Hanne

    2017-01-01

    samples in situ with no prior purification and minimal sample preparation. Lignin chemical formulas and lignin Fourier transform infrared (FTIR) spectra were extracted from mixed spectra by filtering out signals from residual carbohydrates and minerals. From estimations of C, H and O and adjustment...

  16. Effective release of lignin fragments from lignocellulose by lewis acid metal triflates in the lignin-first approach

    NARCIS (Netherlands)

    Huang, X.; Zhu, J.; Koranyi, T.I.; Boot, M.D.; Hensen, E.J.M.

    2016-01-01

    Adding value to lignin, the most complex and recalcitrant fraction in lignocellulosic biomass, is highly relevant to costefficient operation of biorefineries. We report the use of homogeneous metal triflates to rapidly release lignin from biomass. Combined with metal-catalyzed hydrogenolysis, the

  17. Formation of a tyrosine adduct involved in lignin degradation by Trametopsis cervina lignin peroxidase: a novel peroxidase activation mechanism

    Science.gov (United States)

    Yuta Miki; Rebecca Pogni; Sandra Acebes; Fatima Lucas; Elena Fernandez-Fueyo; Maria Camilla Baratto; Maria I. Fernandez; Vivian De Los Rios; Francisco J. Ruiz-duenas; Adalgisa Sinicropi; Riccardo Basosi; Kenneth E. Hammel; Victor Guallar; Angel T. Martinez

    2013-01-01

    LiP (lignin peroxidase) from Trametopsis cervina has an exposed catalytic tyrosine residue (Tyr181) instead of the tryptophan conserved in other lignin-degrading peroxidases. Pristine LiP showed a lag period in VA (veratryl alcohol) oxidation. However, VA-LiP (LiP after treatment with H2O2...

  18. Cinnamic acid 4-hydroxylase of sorghum [Sorghum biocolor (L.) Moench] gene SbC4H1 restricts lignin synthesis in Arabidopsis

    Science.gov (United States)

    Cinnamic acid 4-hydroxylase (C4H) is the first hydroxylase enzyme of the phenylpropanoid pathway, and its content and activity affects the lignin synthesis. In this study, we isolated a C4H gene SbC4H1 from the suppression subtractive hybridization library of brown midrib (bmr) mutants of Sorghum b...

  19. Draft genome sequence of Streptomyces coelicoflavus ZG0656 reveals the putative biosynthetic gene cluster of acarviostatin family α-amylase inhibitors.

    Science.gov (United States)

    Guo, X; Geng, P; Bai, F; Bai, G; Sun, T; Li, X; Shi, L; Zhong, Q

    2012-08-01

    The aims of this study are to obtain the draft genome sequence of Streptomyces coelicoflavus ZG0656, which produces novel acarviostatin family α-amylase inhibitors, and then to reveal the putative acarviostatin-related gene cluster and the biosynthetic pathway. The draft genome sequence of S. coelicoflavus ZG0656 was generated using a shotgun approach employing a combination of 454 and Solexa sequencing technologies. Genome analysis revealed a putative gene cluster for acarviostatin biosynthesis, termed sct-cluster. The cluster contains 13 acarviostatin synthetic genes, six transporter genes, four starch degrading or transglycosylation enzyme genes and two regulator genes. On the basis of bioinformatic analysis, we proposed a putative biosynthetic pathway of acarviostatins. The intracellular steps produce a structural core, acarviostatin I00-7-P, and the extracellular assemblies lead to diverse acarviostatin end products. The draft genome sequence of S. coelicoflavus ZG0656 revealed the putative biosynthetic gene cluster of acarviostatins and a putative pathway of acarviostatin production. To our knowledge, S. coelicoflavus ZG0656 is the first strain in this species for which a genome sequence has been reported. The analysis of sct-cluster provided important insights into the biosynthesis of acarviostatins. This work will be a platform for producing novel variants and yield improvement. © 2012 The Authors. Letters in Applied Microbiology © 2012 The Society for Applied Microbiology.

  20. Analysis of occludin trafficking, demonstrating continuous endocytosis, degradation, recycling and biosynthetic secretory trafficking.

    Directory of Open Access Journals (Sweden)

    Sarah J Fletcher

    Full Text Available Tight junctions (TJs link adjacent cells and are critical for maintenance of apical-basolateral polarity in epithelial monolayers. The TJ protein occludin functions in disparate processes, including wound healing and Hepatitis C Virus infection. Little is known about steady-state occludin trafficking into and out of the plasma membrane. Therefore, we determined the mechanisms responsible for occludin turnover in confluent Madin-Darby canine kidney (MDCK epithelial monolayers. Using various biotin-based trafficking assays we observed continuous and rapid endocytosis of plasma membrane localised occludin (the majority internalised within 30 minutes. By 120 minutes a significant reduction in internalised occludin was observed. Inhibition of lysosomal function attenuated the reduction in occludin signal post-endocytosis and promoted co-localisation with the late endocytic system. Using a similar method we demonstrated that ∼20% of internalised occludin was transported back to the cell surface. Consistent with these findings, significant co-localisation between internalised occludin and recycling endosomal compartments was observed. We then quantified the extent to which occludin synthesis and transport to the plasma membrane contributes to plasma membrane occludin homeostasis, identifying inhibition of protein synthesis led to decreased plasma membrane localised occludin. Significant co-localisation between occludin and the biosynthetic secretory pathway was demonstrated. Thus, under steady-state conditions occludin undergoes turnover via a continuous cycle of endocytosis, recycling and degradation, with degradation compensated for by biosynthetic exocytic trafficking. We developed a mathematical model to describe the endocytosis, recycling and degradation of occludin, utilising experimental data to provide quantitative estimates for the rates of these processes.

  1. Adsorption of cellulase on cellulolytic enzyme lignin from lodgepole pine.

    Science.gov (United States)

    Tu, Maobing; Pan, Xuejun; Saddler, Jack N

    2009-09-09

    Enzymatic hydrolysis of lignocellulosic materials is significantly affected by cellulase adsorption onto the lignocellulosic substrates and lignin. The presence of lignin plays an important role in lignocellulosic hydrolysis and enzyme recycling. Three cellulase preparations (Celluclast, Spezyme CP, and MSUBC) were evaluated to determine their adsorption onto cellulolytic enzyme lignin (CEL) from steam-exploded Lodgepole pine (SELP) and ethanol (organosolv)-pretreated Lodgepole pine (EPLP). The adsorption affinity of cellulase (Celluclast) onto isolated lignin (CEL-EPLP and CEL-SELP) was slightly higher than that from corresponding EPLP and SELP substrates on the basis of the Langmuir constants. Effects of temperature, ionic strength, and surfactant on cellulase adsorption onto isolated lignin were also explored in this study. Thermodynamic analysis of enzyme adsorption onto isolated lignin (Gibbs free energy change DeltaG(0) approximately -30 kJ/mol) indicated this adsorption was a spontaneous process. The addition of surfactant (0.2% w/v) could reduce the adsorption of cellulase onto CEL-SELP by 60%. Two types of adsorption isotherm were compared for cellulase adsorption onto isolated lignin. A Langmuir adsorption isotherm showed better fit for the experimental data than a Freundlich adsorption isotherm.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  3. Characterization of the lignin polymer in Brassicaceae family

    Directory of Open Access Journals (Sweden)

    S. Hemmati

    2017-04-01

    Full Text Available Background and objectives: Residues of medicinal plants after extraction and weeds are suitable candidates for bioethanol production. Significant barriers exist to make the conversion of lignocellulosic feedstock to biofuel cost effective and environmentally friendly; one of which is the lignin polymer. Brassicaceae family is one of the potential targets for biofuel production. The structural characteristics of lignin from Hirschfeldia incana, Sisymbrium altissimum and Cardaria draba were studied in comparison to that of Brassica napus. Methods: Lignin deposition was observed by phloroglucinol and Mäule staining. The total lignin content was determined by Klason method. Maximum UV absorbance and FT-IR spectra were compared. Ratio of syringyl to guaiacyl lignin (S/G ratio as a metric of lignin digestibility was determined by DFRC followed by GC-MS analysis. 1H-NMR spectra of the total lignin was compared with other spectroscopic methods. Results: Staining of thestem cross sections of C. draba showed higher G units in contrast to the higher S units in S. altissimum which was in agreement with 1H-NMR analysis. Total lignin content for H. incana, C. draba and S. altissimum was 27.10%, 23.8% and 24.5%, respectively. The specific maximum UV absorbance appeared between 230-260 nm. FT-IR analysis confirmed the presence of more aromatic structures in the seed maturation stage than the flowering stage. S/G ratio was 0.26, 0.10 and 0.22 for H. incana, C. draba and S. altissimum, respectively.  Conclusion: Except Cardaria draba with the predominance of G subunits in lignin polymer, Hirschfeldia incana and Sisymbrium altissimum are suitable candidates for bioethanol production.

  4. Solid-state 29Si NMR and FTIR analyses of lignin-silica coprecipitates

    DEFF Research Database (Denmark)

    Cabrera Orozco, Yohanna; Cabrera, Andrés; Larsen, Flemming Hofmann

    2016-01-01

    When agricultural residues are processed to ethanol, lignin and silica are some of the main byproducts. Separation of these two products is difficult and the chemical interactions between lignin and silica are not well described. In the present study, the effect of lignin-silica complexing has been...... investigated by characterizing lignin and silica coprecipitates by FTIR and solid state NMR. Silica particles were coprecipitated with three different lignins, three lignin model compounds, and two silanes representing silica-in-lignin model compounds. Comparison of 29Si SP/MAS NMR spectra revealed differences...

  5. Use of [75Se]selenomethionine in immunoglobulin biosynthetic studies

    International Nuclear Information System (INIS)

    Gutman, G.A.; Warner, N.L.; Harris, A.W.; Bowles, A.

    1978-01-01

    The gamma-emitting amino acid analog, [ 75 Se] selenomethionine, has been used as a biosynthetic label for immunoglobulins secreted by plasmacytomas in tissue culture. The secreted products are structurally intact with respect to their antibody combining sites and their class and allotype antigenic specificities. A component of [ 75 Se] selenomethionine preparations was found to bind to fetal calf serum proteins, in a manner releasable by mercaptoethanol, but not by sodium dodecyl sulfate and urea. Methods for circumventing the problems caused by this binding are described. (Auth.)

  6. Insights into lignin degradation and its potential industrial applications.

    Science.gov (United States)

    Abdel-Hamid, Ahmed M; Solbiati, Jose O; Cann, Isaac K O

    2013-01-01

    Lignocellulose is an abundant biomass that provides an alternative source for the production of renewable fuels and chemicals. The depolymerization of the carbohydrate polymers in lignocellulosic biomass is hindered by lignin, which is recalcitrant to chemical and biological degradation due to its complex chemical structure and linkage heterogeneity. The role of fungi in delignification due to the production of extracellular oxidative enzymes has been studied more extensively than that of bacteria. The two major groups of enzymes that are involved in lignin degradation are heme peroxidases and laccases. Lignin-degrading peroxidases include lignin peroxidase (LiP), manganese peroxidase (MnP), versatile peroxidase (VP), and dye-decolorizing peroxidase (DyP). LiP, MnP, and VP are class II extracellular fungal peroxidases that belong to the plant and microbial peroxidases superfamily. LiPs are strong oxidants with high-redox potential that oxidize the major non-phenolic structures of lignin. MnP is an Mn-dependent enzyme that catalyzes the oxidation of various phenolic substrates but is not capable of oxidizing the more recalcitrant non-phenolic lignin. VP enzymes combine the catalytic activities of both MnP and LiP and are able to oxidize Mn(2+) like MnP, and non-phenolic compounds like LiP. DyPs occur in both fungi and bacteria and are members of a new superfamily of heme peroxidases called DyPs. DyP enzymes oxidize high-redox potential anthraquinone dyes and were recently reported to oxidize lignin model compounds. The second major group of lignin-degrading enzymes, laccases, are found in plants, fungi, and bacteria and belong to the multicopper oxidase superfamily. They catalyze a one-electron oxidation with the concomitant four-electron reduction of molecular oxygen to water. Fungal laccases can oxidize phenolic lignin model compounds and have higher redox potential than bacterial laccases. In the presence of redox mediators, fungal laccases can oxidize non

  7. Synthesis of novel ionic liquids from lignin-derived compounds

    Science.gov (United States)

    Socha, Aaron; Singh, Seema; Simmons, Blake A.; Bergeron, Maxime

    2017-09-19

    Methods and compositions are provided for synthesizing ionic liquids from lignin derived compounds comprising: contacting a starting material comprising lignin with a depolymerization agent to depolymerize the lignin and form a mixture of aldehyde containing compounds; contacting the mixture of aldehyde containing compounds with an amine under conditions suitable to convert the mixture of aldehyde containing compounds to a mixture of amine containing compounds; and contacting the mixture of amine containing compounds with an acid under conditions suitable to form an ammonium salt, thereby preparing the ionic liquid.

  8. Radiolysis of lignin: Prospective mechanism of high-temperature decomposition

    Science.gov (United States)

    Ponomarev, A. V.

    2017-12-01

    The range of the radiation-thermal processes resulting in conversion of lignin into monomeric phenols is considered. Statistically the most probable places of macromolecule ionization are aromatic units. Release of phenolic products from a lignin macromolecule is the multistage process beginning via fragmentation of primary cation-radicals. Reactions of electrons and small radicals with macromolecules, also as degradation of cation-radicals, result in formation of phenoxyl radicals. Macroradicals possess lower heat stability in comparison with macromolecules. Thermal decomposition of macroradicals leads to release of monohydric and dihydric phenols. The probability of benzenediols formation increases in the presence of alkanes. As noted, partial transformation of lignin into charcoal is inevitable.

  9. Pyrolysis-gas chromatography-mass spectrometry of isolated, synthetic and degraded lignins

    Energy Technology Data Exchange (ETDEWEB)

    Saiz-Jimenez, C.; De Leeuw, J.W.

    1984-01-01

    Curie-point pyrolysis-gas chromatography-mass spectrometry was applied to study the chemical structure of sound and fungus degraded, industrial and synthetic lignins. Pyrolysis products reflected in some detail the structural units present in the lignin polymer. Thus, sound spruce lignin yielded trans-isoeugenol coniferaldehyde and trans-coniferyl alcohol as major pyrolysis products. Biodegraded lignin yielded oxidized units, including vanillin, acetoguaiacone, methyl vanillate, propioguaiacone, vanilloyl methyl ketone and vanillic acid as major products. Kraft lignin also showed evidence of oxidation, although not as much as the biodegraded lignin. Major products from this industrial lignin were guaiacol, methylguaiacol, vinylguaiacol and homovanillic acid. Results indicated that synthetic lignin duplicates fairly well the structure of natural lignin. However, coniferylaldehyde and trans-coniferyl alcohol were the dominant products only from the synthetic lignin, indicating the presence of large amounts of coniferyl alcohol and coniferylaldehyde end groups. 21 references.

  10. Oxidative polymerization of lignins by laccase in water-acetone mixture.

    Science.gov (United States)

    Fiţigău, Ionița Firuța; Peter, Francisc; Boeriu, Carmen Gabriela

    2013-01-01

    The enzymatic oxidative polymerization of five technical lignins with different molecular properties, i.e. Soda Grass/Wheat straw Lignin, Organosolv Hardwood Lignin, Soda Wheat straw Lignin, Alkali pretreated Wheat straw Lignin, and Kraft Softwood was studied. All lignins were previously fractionated by acetone/water 50:50 (v/v) and the laccase-catalyzed polymerization of the low molecular weight fractions (Mw Reactivity of lignin substrates in laccase-catalyzed reactions was determined by monitoring the oxygen consumption. The oxidation reactions in 50% acetone in water mixture proceed with high rate for all tested lignins. Polymerization products were analyzed by size exclusion chromatography, FT-IR, and (31)P-NMR and evidence of important lignin modifications after incubation with laccase. Lignin polymers with higher molecular weight (Mw up to 17500 g/mol) were obtained. The obtained polymers have potential for applications in bioplastics, adhesives and as polymeric dispersants.

  11. Effects of lignin and surfactant on adsorption and hydrolysis of cellulases on cellulose

    OpenAIRE

    Li, Yanfei; Sun, Zongping; Ge, Xiaoyan; Zhang, Junhua

    2016-01-01

    Background Considerable works have been reported concerning the obstruction of enzymatic hydrolysis efficiency by lignin. However, there is a lack of information about the influence of lignin on the adsorption of cellulases on cellulose, along with the hydrolytic activity of the cellulases adsorbed on lignin. In addition, limited discovery has been reported about the influence of additives on cellulase desorption from lignin and lignocellulosic materials. In this work, the effects of lignin o...

  12. Alkali-treated kraft lignin as a component in flakeboard eesins

    Science.gov (United States)

    Mon-Lin Kuo; Chung-Yun Hse; Dee-Hua Huang

    1991-01-01

    Southern pine kraft lignin was reacted with NaOH (15 and 20% based on dry lignin) at 170, 200, and 250°C for 30 and 60 min. Sweetgum flake boards bonded with phenolic resins containing 50% hydroxymethylated lignin prepared from some of the alkali treated lignins were compared with boards bonded with a neat PF resin. Results indicate that boards bonded with lignin-...

  13. Biosynthetic multitasking facilitates thalassospiramide structural diversity in marine bacteria

    KAUST Repository

    Ross, Avena C.

    2013-01-23

    Thalassospiramides A and B are immunosuppressant cyclic lipopeptides first reported from the marine α-proteobacterium Thalassospira sp. CNJ-328. We describe here the discovery and characterization of an extended family of 14 new analogues from four Tistrella and Thalassospira isolates. These potent calpain 1 protease inhibitors belong to six structure classes in which the length and composition of the acylpeptide side chain varies extensively. Genomic sequence analysis of the thalassospiramide-producing microbes revealed related, genus-specific biosynthetic loci encoding hybrid nonribosomal peptide synthetase/polyketide synthases consistent with thalassospiramide assembly. The bioinformatics analysis of the gene clusters suggests that structural diversity, which ranges from the 803.4 Da thalassospiramide C to the 1291.7 Da thalassospiramide F, results from a complex sequence of reactions involving amino acid substrate channeling and enzymatic multimodule skipping and iteration. Preliminary biochemical analysis of the N-terminal nonribosomal peptide synthetase module from the Thalassospira TtcA megasynthase supports a biosynthetic model in which in cis amino acid activation competes with in trans activation to increase the range of amino acid substrates incorporated at the N terminus. © 2012 American Chemical Society.

  14. Biosynthetic multitasking facilitates thalassospiramide structural diversity in marine bacteria

    KAUST Repository

    Ross, Avena C.; Xü , Ying; Lu, Liang; Kersten, Roland D.; Shao, Zongze; Al-Suwailem, Abdulaziz M.; Dorrestein, Pieter C.; Qian, Peiyuan; Moore, Bradley S.

    2013-01-01

    Thalassospiramides A and B are immunosuppressant cyclic lipopeptides first reported from the marine α-proteobacterium Thalassospira sp. CNJ-328. We describe here the discovery and characterization of an extended family of 14 new analogues from four Tistrella and Thalassospira isolates. These potent calpain 1 protease inhibitors belong to six structure classes in which the length and composition of the acylpeptide side chain varies extensively. Genomic sequence analysis of the thalassospiramide-producing microbes revealed related, genus-specific biosynthetic loci encoding hybrid nonribosomal peptide synthetase/polyketide synthases consistent with thalassospiramide assembly. The bioinformatics analysis of the gene clusters suggests that structural diversity, which ranges from the 803.4 Da thalassospiramide C to the 1291.7 Da thalassospiramide F, results from a complex sequence of reactions involving amino acid substrate channeling and enzymatic multimodule skipping and iteration. Preliminary biochemical analysis of the N-terminal nonribosomal peptide synthetase module from the Thalassospira TtcA megasynthase supports a biosynthetic model in which in cis amino acid activation competes with in trans activation to increase the range of amino acid substrates incorporated at the N terminus. © 2012 American Chemical Society.

  15. Nano-lignin filled natural rubber composites: Preparation and characterization

    Directory of Open Access Journals (Sweden)

    C. Jiang

    2013-05-01

    Full Text Available This paper presents a novel strategy to prepare nano-lignin and its composites with natural rubber. The nanolignin was ontained by fabricating colloidal lignin-Poly (diallyldimethylammonium chloride (PDADMAC complexes (LPCs via self-assembly technology. The characteristics of LPCs were investigated by zeta potential, dynamic light scattering (DLS, transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FTIR and ultraviolet – visible (UV-vis absorption measurements. The results indicated that PDADMAC intensively interacted with lignin by cation-π and π-π interactions, and lignin particles were stable in aqueous solution with an average particle size less than 100 nm. LPCs accelerated the vulcanization of NR/LPCs nanocomposites. Morphological studies and Dynamic mechanical analysis (DMA showed the homogeneous dispersion of LPCs in the NR matrix and the strong interfacial adhesion between them. The nanoscale dispersion of LPCs significantly enhanced the thermal stability and mechanical properties of NR/LPCs nanocomposites.

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

    Directory of Open Access Journals (Sweden)

    Daniel Humpert

    2016-09-01

    Full Text Available 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.

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

    Science.gov (United States)

    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

  18. Removal of oil palm trunk lignin in ammonium hydroxide pretreatment

    Science.gov (United States)

    Az-Zahraa, Balqis; Zakaria, Sarani; Daud, Muhammad F. B.; Jaafar, Sharifah Nabihah Syed

    2018-04-01

    Alkaline pretreatment using ammonium hydroxide, NH4OH serves as one of a process to remove lignin from lignocellulosic biomass such as oil palm trunk fiber. In this study, the effect of NH4OH pretreatment on removal of oil palm trunk lignin was investigated. The oil palm trunk fiber was dissolved in NH4OH with different concentrations (6, 8 and 10 %), different duration (3, 5 and 7 h) and temperatures (60, 80 and 100 °C). The samples were analyzed by using UV-Vis to estimate the concentration of extracted lignin. The result indicates that the optimum conditions to gain maximum extracted lignin were 8% NH4OH, 100 °C and 5 h with concentration of 64 mgL-1 while the lowest was at 6% NH4OH, 100 °C and 5 h with concentration of 62.5 mgL-1.

  19. Analytical protocols for characterisation of sulphur-free lignin

    NARCIS (Netherlands)

    Gosselink, R.J.A.; Abächerli, A.; Semke, H.; Malherbe, R.; Käuper, P.; Nadif, A.; Dam, van J.E.G.

    2004-01-01

    Interlaboratory tests for chemical characterisation of sulphur-free lignins were performed by five laboratories to develop useful analytical protocols, which are lacking, and identify quality-related properties. Protocols have been established for reproducible determination of the chemical

  20. Biological and Catalytic Conversion of Sugars and Lignin | Bioenergy | NREL

    Science.gov (United States)

    Sugars and Lignin Our research group, comprised of staff scientists, postdoctoral associates, students synthase enzyme, represented as "surfaces" or "blobs," embedded in a lipid bilayer "blobs," embedded in a lipid bilayer, represented as yellow multi-jointed strands. Above this

  1. Fast Pyrolysis of Lignin Using a Pyrolysis Centrifuge Reactor

    DEFF Research Database (Denmark)

    Trinh, Ngoc Trung; Jensen, Peter Arendt; Sárossy, Zsuzsa

    2013-01-01

    Fast pyrolysis of lignin from an ethanol plant was investigated on a lab scale pyrolysis centrifuge reactor (PCR) with respect to pyrolysis temperature, reactor gas residence time, and feed rate. A maximal organic oil yield of 34 wt % dry basis (db) (bio-oil yield of 43 wt % db) is obtained...... at temperatures of 500−550 °C, reactor gas residence time of 0.8 s, and feed rate of 5.6 g/min. Gas chromatography mass spectrometry and size-exclusion chromatography were used to characterize the Chemical properties of the lignin oils. Acetic acid, levoglucosan, guaiacol, syringols, and p-vinylguaiacol are found...... components and molecular mass distribution of the lignin oils. The obtained lignin oil has a very different components composition when compared to a beech wood oil....

  2. Downregulation of the UDP-arabinomutase gene in switchgrass (Panicum virgatum L. results in increased cell wall lignin while reducing arabinose-glycans

    Directory of Open Access Journals (Sweden)

    Jonathan Duran Willis

    2016-10-01

    Full Text Available Switchgrass (Panicum virgatum L. is a C4 perennial prairie grass and a lignocellulosic biofuels feedstock. Saccharification and biofuel yields are inhibited by the plant cell wall’s natural recalcitrance against enzymatic degradation. Plant hemicellulose polysaccharides such as arabinoxylans structurally support and crosslink other cell wall polymers. Grasses have predominately Type II cell walls that are abundant in arabinoxylan, which comprise nearly 25% of aboveground biomass. A primary component of arabinoxylan synthesis is uridine diphosphate (UDP linked to arabinofuranose (Araf. A family of UDP-arabinopyranose mutase/reversible glycosylated polypeptides (UAM/RGPs catalyze the interconversion between UDP-arabinopyranose (UDP-Arap and UDP-Araf. In switchgrass we knocked down expression of the endogenous PvUAM1 gene via RNAi to investigate its role in cell wall recalcitrance in the feedstock. PvUAM1 encodes a switchgrass homolog of UDP-arabinose mutase, which converts UDP-Arap to UDP-Araf. Each transgenic line contained between one to at least seven T-DNA insertions, resulting in some cases, a 95% reduction of native PvUAM1 transcript in stem internodes. Transgenic plants had increased pigmentation in vascular tissues at nodes, but were otherwise morphologically similar to non-transgenics. There was decreased cell wall-associated arabinose in leaves and stems by over 50%, but there was an increase in cellulose in these organs. In addition, there was a commensurate change in arabinose side chain extension. Cell wall lignin composition was altered with a concurrent increase in lignin content and transcript abundance of lignin biosynthetic genes in mature tillers. Enzymatic saccharification efficiency was unchanged in the transgenic plants relative to the control, but had increased glucose in cell walls. The increased glucose detected in stems and leaves indicates that attenuation of PvUAM1 expression might have downstream effects on starch

  3. Transcription factors for modification of lignin content in plants

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  5. Lignin chemical degradation using redistribution mechanism and its biomass applications

    OpenAIRE

    Nanayakkara, Sepa Yasandrika

    2017-01-01

    Lignin is one of the most abundant renewable raw materials available on earth and it has the potential to yield valuable low molecular weight aromatic compounds if it can be depolymerized selectively. Despite its unique characteristics as a natural product with multiple chemical and biophysical functionalities, it is largely under-exploited, because of the lack of available methods that effect depolymerization in a selective manner. One of the dominant linkages in lignin has a similar ary...

  6. Improved Lignin Polyurethane Properties with Lewis Acid Treatment

    OpenAIRE

    Chung, Hoyong; Washburn, Newell R.

    2012-01-01

    Chemical modification strategies to improve the mechanical properties of lignin-based polyurethanes are presented. We hypothesized that treatment of lignin with Lewis acids would increase the concentration of hydroxyl groups available to react with diisocyanate monomers. Under the conditions used, hydrogen bromide-catalyzed modification resulted in a 28% increase in hydroxyl group content. Associated increases in hydrophilicity of solvent-cast thin films were also recorded as evidenced by ...

  7. Chemical reactivity of alkali lignin modified with laccase

    International Nuclear Information System (INIS)

    Sun, Yong; Qiu, Xueqing; Liu, Yunquan

    2013-01-01

    The modification of alkali lignin with laccase was investigated. The structural change of lignin was analyzed. The sulfonation reactivity was measured by the content of sulfonic group. The results showed the sulfonation reactivity increased to some extent under the condition of atmosphere pressure, but decreased under the condition of 0.3 MPa oxygen pressure. The analysis of Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) showed the cleavage of various ether linkages and demethylation took place in the structure of lignin to certain extent during modification with laccase, which contributed to the improvement of sulfonation reactivity. Under the condition of 0.3 MPa oxygen pressure, the ratio of s/g (guaiacyl/syringyl) increased after modification, which reduced the sulfonation reactivity of lignin. Simultaneously partial polymerization reaction, such as 4-O-5′, β-5, 5-5 and other reaction in the aromatic ring decreased the activity sites of C 2 , C 5 and C 6 . Abundant polymerization reaction of α-O increased steric hindrance of C 2 and C 6 in aromatic ring, resulting in low sulfonation reactivity of lignin. -- Highlights: ► The modification of alkali lignin with laccase was investigated. ► The sulfonation reactivity increased under the condition of atmosphere pressure. ► More content of guaiacyl and hydroxy, the less content of methoxyl, syringyl can enhance the sulfonation reactivity of lignin. ► Partial moieties polymerized each other with α-O linkgages during treatment with laccase under oxygen pressure. ► The steric hindrance on C 2 and C 6 in aromatic ring resulted in low sulfonation reaction reactivity of lignin

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

    Science.gov (United States)

    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.

  9. Density functional theory study of spirodienone stereoisomers in lignin

    Science.gov (United States)

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

    2017-01-01

    The spirodienone structure in lignin is a relatively recent discovery, and it has been found to occur in lignin of various plant species at concentrations of ∼3%, which is sufficiently high to be important for better understanding of its properties and reactivity. The cyclic structure, with a β-1 bond, has been proposed to be a precursor for acyclic β-1 linkages in...

  10. Dissolved Vanillin as Tracer for Estuarine Lignin Conversion

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Cellulase-lignin interactions in the enzymatic hydrolysis of lignocellulose

    Energy Technology Data Exchange (ETDEWEB)

    Rahikainen, J.

    2013-11-01

    Today, the production of transportation fuels and chemicals is heavily dependent on fossil carbon sources, such as oil and natural gas. Their limited availability and the environmental concerns arising from their use have driven the search for renewable alternatives. Lignocellulosic plant biomass is the most abundant, but currently underutilised, renewable carbon-rich resource for fuel and chemical production. Enzymatic degradation of structural polysaccharides in lignocellulose produces soluble carbohydrates that serve as ideal precursors for the production of a vast amount of different chemical compounds. The difficulty in full exploitation of lignocellulose for fuel and chemical production lies in the complex and recalcitrant structure of the raw material. Lignocellulose is mainly composed of structural polysaccharides, cellulose and hemicellulose, but also of lignin, which is an aromatic polymer. Enzymatic degradation of cellulose and hemicellulose is restricted by several substrate- and enzyme-related factors, among which lignin is considered as one of the most problematic issues. Lignin restricts the action of hydrolytic enzymes and enzyme binding onto lignin has been identified as a major inhibitory mechanism preventing efficient hydrolysis of lignocellulosic feedstocks. In this thesis, the interactions between cellulase enzymes and lignin-rich compounds were studied in detail and the findings reported in this work have the potential to help in controlling the harmful cellulase-lignin interactions, and thus improve the biochemical processing route from lignocellulose to fuels and chemicals.

  13. Abundance and reactivity of dibenzodioxocins in softwood lignin.

    Science.gov (United States)

    Argyropoulos, Dimitris S; Jurasek, Lubo; Kristofová, Lívia; Xia, Zhicheng; Sun, Yujun; Palus, Ernest

    2002-02-13

    To define the abundance and comprehend the reactivity of dibenzodioxocins in lignin, model compound studies, specific degradation experiments on milled wood lignin, and molecular modeling calculations have been performed. Quantitative (31)P NMR measurements of the increase of biphenolic hydroxyl groups formed after a series of alkaline degradations in the presence of hydrosulfide anions (kraft conditions) showed the presence of 3.7 dibenzodioxocin rings/100 C9 units in milled wood lignin. The DFRC degradation protocol (Derivatization Followed by Reductive Cleavage) was chosen as an independent means to estimate their abundance. Initial experiments with a dibenzodioxocin model compound, trans-6,7-dihydro-7-(4-hydroxy-3-methoxyphenyl)-4,9-dimethoxy-2,11-dipropyldibenzo[e,g][1,4]dioxocin-6-ylmethanol, showed that it is not cleaved under DFRC conditions, but rather it isomerizes into a cyclic oxepine structure. Steric effects precluded this isomerization from occurring when DFRC was applied to milled wood lignin. Instead, monoacetylated biphenolic moieties were released and quantified by (31)P NMR, at 4.3 dibenzodioxocin rings/100 C9 units. The dibenzodioxocin content in residual lignins isolated from kraft pulps delignified to various degrees showed that during pulp delignification, the initial rate of dibenzodioxocin removal was considerably greater than the cleavage rate of arylglycerol-beta-aryl ether bonds. The activation energy for the degradation of dibenzodioxocins under kraft conditions in milled wood lignin was 96 +/- 9 kJ/mol, similar to that of arylglycerol-beta-aryl ether bond cleavage.

  14. Metal Triflates for the Production of Aromatics from Lignin.

    Science.gov (United States)

    Deuss, Peter J; Lahive, Ciaran W; Lancefield, Christopher S; Westwood, Nicholas J; Kamer, Paul C J; Barta, Katalin; de Vries, Johannes G

    2016-10-20

    The depolymerization of lignin into valuable aromatic chemicals is one of the key goals towards establishing economically viable biorefineries. In this contribution we present a simple approach for converting lignin to aromatic monomers in high yields under mild reaction conditions. The methodology relies on the use of catalytic amounts of easy-to-handle metal triflates (M(OTf) x ). Initially, we evaluated the reactivity of a broad range of metal triflates using simple lignin model compounds. More advanced lignin model compounds were also used to study the reactivity of different lignin linkages. The product aromatic monomers were either phenolic C2-acetals obtained by stabilization of the aldehyde cleavage products by reaction with ethylene glycol or methyl aromatics obtained by catalytic decarbonylation. Notably, when the method was ultimately tested on lignin, especially Fe(OTf) 3 proved very effective and the phenolic C2-acetal products were obtained in an excellent, 19.3±3.2 wt % yield. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Signatures of cinnamyl alcohol dehydrogenase deficiency in poplar lignins.

    Science.gov (United States)

    Lapierre, Catherine; Pilate, Gilles; Pollet, Brigitte; Mila, Isabelle; Leplé, Jean-Charles; Jouanin, Lise; Kim, Hoon; Ralph, John

    2004-02-01

    A series of transgenic poplars down-regulated for cinnamyl alcohol dehydrogenase (CAD) was analyzed by thioacidolysis. Among the lignin-derived monomers, the indene compounds that were recently shown to originate from sinapaldehyde incorporated into lignins through 8-O-4-cross-coupling, were found to increase as a function of CAD deficiency level. While these syringyl markers were recovered in substantial amounts in the most severely depressed lines, the markers for coniferaldehyde incorporation were recovered in only low amounts. In conjunction with these additional sinapaldehyde units and relative to the control samples, lignins in CAD-deficient poplar lines had less conventional syringyl-units and beta-O-4-bonds and more free phenolic groups. We found that almost half of the polymers in the most deficient lines could be solubilized in alkali and at room temperature. This unusual behavior suggests that lignins in CAD-deficient poplars occur as small, alkali-leachable lignin domains. That mainly sinapaldehyde incorporates into the lignins of CAD-deficient poplars suggests that the recently identified sinapyl alcohol dehydrogenase (SAD), which is structurally distinct from the CAD enzyme targeted herein, does not play any substantial role in constitutive lignification in poplar.

  16. A radioimmunoassay for lignin in plant cell walls

    International Nuclear Information System (INIS)

    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 β-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 ηg/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. 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 2 delignification. The RIA was found to be less sensitive than expected, so several avenues for improving the method are discussed

  17. System analyse cellulose ethanol in combines - Combustion characterisation of lignin from cellulose based ethanol production; Systemanalys foer cellulosabaserad etanol i kombinat - Foerbraenningskarakterisering av lignin fraan cellulosabaserad etanolproduktion

    Energy Technology Data Exchange (ETDEWEB)

    Lindstedt, Jan; Wingren, Anders; Magnusson, Staffan; Wiinikka, Henrik; Westbom, Urban; Lidman, Marcus; Groenberg, Carola

    2012-02-15

    In this work 3 different hydrolysed lignin fractions produced from Sugarcane Bagasse, Spruce and Wheat Straw were burned in a 150 kW horizontal furnace equipped with a powder burner to assess the combustion behaviour of hydrolysed lignin fuels. The combustion experiments showed that the feeding properties of all three lignin fractions were better compared to ordinary wood powder

  18. Noble metal catalyzed aqueous phase hydrogenation and hydrodeoxygenation of lignin-derived pyrolysis oil and related model compounds.

    Science.gov (United States)

    Mu, Wei; Ben, Haoxi; Du, Xiaotang; Zhang, Xiaodan; Hu, Fan; Liu, Wei; Ragauskas, Arthur J; Deng, Yulin

    2014-12-01

    Aqueous phase hydrodeoxygenation of lignin pyrolysis oil and related model compounds were investigated using four noble metals supported on activated carbon. The hydrodeoxygenation of guaiacol has three major reaction pathways and the demethylation reaction, mainly catalyzed by Pd, Pt and Rh, produces catechol as the products. The presence of catechol and guaiacol in the reaction is responsible for the coke formation and the catalysts deactivation. As expected, there was a significant decrease in the specific surface area of Pd, Pt and Rh catalysts during the catalytic reaction because of the coke deposition. In contrast, no catechol was produced from guaiacol when Ru was used so a completely hydrogenation was accomplished. The lignin pyrolysis oil upgrading with Pt and Ru catalysts further validated the reaction mechanism deduced from model compounds. Fully hydrogenated bio-oil was produced with Ru catalyst. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Impact of lignins isolated from pretreated lignocelluloses on enzymatic cellulose saccharification.

    Science.gov (United States)

    Barsberg, Søren; Selig, Michael Joseph; Felby, Claus

    2013-02-01

    Lignins were enzymatically isolated from corn stover and wheat straw samples and subjected to hydrothermal or wet oxidation pretreatments for enzyme adsorption experimentations. Lignin contents of the isolates ranged from 26 to 71 % (w/w); cellulose ranged from 3 to 22 % (w/w); xylan from 0.7 to 6 % (w/w) and ash was from 5.8 to 30 % (w/w). ATR-IR analyses indicated significant and similar levels of calcium in all lignin isolates. Commercial cellulase adsorption studies showed that the presence of these lignins had no significant impact on the total amount of adsorbed enzyme in cellulose and cellulose-lignin systems. Consequently, the presence of the lignins had minimal effect, if any, on enzymatic cellulose conversion. Furthermore, this result, coupled with significant calcium levels in the isolated lignins, supports previous work suggesting lignin-calcium complexes reduce enzyme-lignin interactions.

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

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Ryan [GrafTech International Holdings Inc.; Naskar, Amit [Oak Ridge National Laboratory; Gallego, Nidia [Oak Ridge National Laboratory; Dai, Xuliang [GrafTech International Holdings Inc.; Hausner, Andrew [GrafTech International Holdings Inc.

    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.

  1. Revealing the fate of the phenylcoumaran linkage during lignin oxidation reactions.

    Science.gov (United States)

    Lahive, Ciaran W; Lancefield, Christopher S; Codina, Anna; Kamer, Paul C J; Westwood, Nicholas J

    2018-03-14

    The fate of most lignin linkages, other than the β-O-4, under selective oxidation conditions is largely unknown. In this work we use advanced β-5 lignin model compounds to identify the fate of phenylcoumaran units in a softwood lignin during oxidation with DDQ. By using model compounds combined with detailed characterisation of the oxidised lignin polymer using HSQC and HMBC NMR we show that phenylcoumarones are a major product, and therefore constitute a novel non-native β-5 linkage in oxidised lignins. Additionally, the reactivity of these units in lignin led us to further investigate their connectivity in lignin, showing that they are found as both phenolic and etherified units. The findings and approach developed here will help improve the efficiency of selective oxidative lignin depolymerisation processes, particularly those aimed at the upgrading of softwood lignin in which phenylcoumarans are a major linkage.

  2. Construction and Optimization of a Heterologous Pathway for Protocatechuate Catabolism in Escherichia coli Enables Bioconversion of Model Aromatic Compounds.

    Science.gov (United States)

    Clarkson, Sonya M; Giannone, Richard J; Kridelbaugh, Donna M; Elkins, James G; Guss, Adam M; Michener, Joshua K

    2017-09-15

    The production of biofuels from lignocellulose yields a substantial lignin by-product stream that currently has few applications. Biological conversion of lignin-derived compounds into chemicals and fuels has the potential to improve the economics of lignocellulose-derived biofuels, but few microbes are able both to catabolize lignin-derived aromatic compounds and to generate valuable products. While Escherichia coli has been engineered to produce a variety of fuels and chemicals, it is incapable of catabolizing most aromatic compounds. Therefore, we engineered E. coli to catabolize protocatechuate, a common intermediate in lignin degradation, as the sole source of carbon and energy via heterologous expression of a nine-gene pathway from Pseudomonas putida KT2440. We next used experimental evolution to select for mutations that increased growth with protocatechuate more than 2-fold. Increasing the strength of a single ribosome binding site in the heterologous pathway was sufficient to recapitulate the increased growth. After optimization of the core pathway, we extended the pathway to enable catabolism of a second model compound, 4-hydroxybenzoate. These engineered strains will be useful platforms to discover, characterize, and optimize pathways for conversions of lignin-derived aromatics. IMPORTANCE Lignin is a challenging substrate for microbial catabolism due to its polymeric and heterogeneous chemical structure. Therefore, engineering microbes for improved catabolism of lignin-derived aromatic compounds will require the assembly of an entire network of catabolic reactions, including pathways from genetically intractable strains. Constructing defined pathways for aromatic compound degradation in a model host would allow rapid identification, characterization, and optimization of novel pathways. We constructed and optimized one such pathway in E. coli to enable catabolism of a model aromatic compound, protocatechuate, and then extended the pathway to a related

  3. The oxylipin pathway in Arabidopsis.

    Science.gov (United States)

    Creelman, Robert A; Mulpuri, Rao

    2002-01-01

    Oxylipins are acyclic or cyclic oxidation products derived from the catabolism of fatty acids which regulate many defense and developmental pathways in plants. The dramatic increase in the volume of publications and reviews on these compounds since 1997 documents the increasing interest in this compound and its role in plants. Research on this topic has solidified our understanding of the chemistry and biosynthetic pathways for oxylipin production. However, more information is still needed on how free fatty acids are produced and the role of beta-oxidation in the biosynthetic pathway for oxylipins. It is also becoming apparent that oxylipin content and composition changes during growth and development and during pathogen or insect attack. Oxylipins such as jasmonic acid (JA) or 12-oxo-phytodienoic acid modulate the expression of numerous genes and influence specific aspects of plant growth, development and responses to abiotic and biotic stresses. Although oxylipins are believed to act alone, several examples were presented to illustrate that JA-induced responses are modulated by the type and the nature of crosstalk with other signaling molecules such as ethylene and salicylic acid. How oxylipins cause changes in gene expression and instigate a physiological response is becoming understood with the isolation of mutations in both positive and negative regulators in the jasmonate signaling pathway and the use of cDNA microarrays.

  4. Plasmid-encoded biosynthetic genes alleviate metabolic disadvantages while increasing glucose conversion to shikimate in an engineered Escherichia coli strain.

    Science.gov (United States)

    Rodriguez, Alberto; Martínez, Juan A; Millard, Pierre; Gosset, Guillermo; Portais, Jean-Charles; Létisse, Fabien; Bolivar, Francisco

    2017-06-01

    Metabolic engineering strategies applied over the last two decades to produce shikimate (SA) in Escherichia coli have resulted in a battery of strains bearing many expression systems. However, the effects that these systems have on the host physiology and how they impact the production of SA are still not well understood. In this work we utilized an engineered E. coli strain to determine the consequences of carrying a vector that promotes SA production from glucose with a high-yield but that is also expected to impose a significant cellular burden. Kinetic comparisons in fermentors showed that instead of exerting a negative effect, the sole presence of the plasmid increased glucose consumption without diminishing the growth rate. By constitutively expressing a biosynthetic operon from this vector, the more active glycolytic metabolism was exploited to redirect intermediates toward the production of SA, which further increased the glucose consumption rate and avoided excess acetate production. Fluxomics and metabolomics experiments revealed a global remodeling of the carbon and energy metabolism in the production strain, where the increased SA production reduced the carbon available for oxidative and fermentative pathways. Moreover, the results showed that the production of SA relies on a specific setup of the pentose phosphate pathway, where both its oxidative and non-oxidative branches are strongly activated to supply erythrose-4-phosphate and balance the NADPH requirements. This work improves our understanding of the metabolic reorganization observed in E. coli in response to the plasmid-based expression of the SA biosynthetic pathway. Biotechnol. Bioeng. 2017;114: 1319-1330. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  5. Extending the biosynthetic repertoires of cyanobacteria and chloroplasts

    DEFF Research Database (Denmark)

    Nielsen, Agnieszka Janina Zygadlo; Mellor, Silas Busck; Vavitsas, Konstantinos

    2016-01-01

    The chloroplasts found in plants and algae, and photosynthetic microorganisms such as cyanobacteria, are emerging hosts for sustainable production of valuable biochemicals, using only inorganic nutrients, water, CO2 and light as inputs. In the past decade, many bioengineering efforts have focused...... on metabolic engineering and synthetic biology in the chloroplast or in cyanobacteria for the production of fuels, chemicals, as well as complex, high-value bioactive molecules. Biosynthesis of all these compounds can be performed in photosynthetic organelles/organisms by heterologous expression...... of chloroplasts and cyanobacteria as biosynthetic compartments and hosts, and we estimate the production levels to be expected from photosynthetic hosts in light of the fraction of electrons and carbon that can potentially be diverted from photosynthesis. The supply of reducing power, in the form of electrons...

  6. An indigoidine biosynthetic gene cluster from Streptomyces chromofuscus ATCC 49982 contains an unusual IndB homologue.

    Science.gov (United States)

    Yu, Dayu; Xu, Fuchao; Valiente, Jonathan; Wang, Siyuan; Zhan, Jixun

    2013-01-01

    A putative indigoidine biosynthetic gene cluster was located in the genome of Streptomyces chromofuscus ATCC 49982. The silent 9.4-kb gene cluster consists of five open reading frames, named orf1, Sc-indC, Sc-indA, Sc-indB, and orf2, respectively. Sc-IndC was functionally characterized as an indigoidine synthase through heterologous expression of the enzyme in both Streptomyces coelicolor CH999 and Escherichia coli BAP1. The yield of indigoidine in E. coli BAP1 reached 2.78 g/l under the optimized conditions. The predicted protein product of Sc-indB is unusual and much larger than any other reported IndB-like protein. The N-terminal portion of this enzyme resembles IdgB and the C-terminal portion is a hypothetical protein. Sc-IndA and/or Sc-IndB were co-expressed with Sc-IndC in E. coli BAP1, which demonstrated the involvement of Sc-IndB, but not Sc-IndA, in the biosynthetic pathway of indigoidine. The yield of indigoidine was dramatically increased by 41.4 % (3.93 g/l) when Sc-IndB was co-expressed with Sc-IndC in E. coli BAP1. Indigoidine is more stable at low temperatures.

  7. Expression of eicosanoid biosynthetic and catabolic enzymes in peritoneal endometriosis.

    Science.gov (United States)

    Lousse, J-C; Defrère, S; Colette, S; Van Langendonckt, A; Donnez, J

    2010-03-01

    Increased peritoneal eicosanoid concentrations have been reported in endometriosis patients and might be important in disease-associated pain and inflammation. Here, we evaluated the expression of key biosynthetic and catabolic enzymes involved in this abnormal eicosanoid production in peritoneal macrophages and endometriotic lesions. Peritoneal macrophages, endometriotic lesions and matched eutopic endometrium were collected from endometriosis patients (n = 40). Peritoneal macrophages and eutopic endometrium samples were also collected from disease-free women (n = 25). Expression of type IIA secretory phospholipase A(2) (sPLA(2)-IIA), cyclooxygenase-2 (COX-2), microsomal prostaglandin E synthase-1 (mPGES-1), 15-hydroxyprostaglandin dehydrogenase (15-PGDH) and 5-lipoxygenase (5-LO) was quantified by real-time PCR, and these five key enzymes were localized by immunohistochemistry. sPLA(2)-IIA, COX-2 and mPGES-1 mRNA was significantly increased in peritoneal macrophages of endometriosis patients compared with controls (P = 0.006, P = 0.016 and P = 0.025, respectively). In endometriosis patients, sPLA(2)-IIA, mPGES-1 and 15-PGDH mRNA was significantly enhanced in peritoneal lesions compared with matched eutopic endometrium (P endometriosis group compared with controls (P = 0.023). Finally, sPLA(2)-IIA, COX-2, mPGES-1 and 15-PGDH immunostaining was found mainly in endometrial glands, whereas 5-LO was distributed throughout the glands and stroma. Our study highlights an imbalance between eicosanoid biosynthesis and degradation in endometriosis patients. Both peritoneal macrophages and endometriotic lesions may be involved. Research into new molecules inhibiting biosynthetic enzymes (such as sPLA(2)-IIA and mPGES-1) and/or activating catabolic enzymes (such as 15-PGDH) may prove to be a major field of investigation in the development of targeted medical therapies.

  8. Impact of lignins isolated from pretreated lignocelluloses on enzymatic cellulose saccharification

    DEFF Research Database (Denmark)

    Barsberg, Søren Talbro; Selig, Michael Joseph; Felby, Claus

    2013-01-01

    and cellulose-lignin systems. Consequently, the presence of the lignins had minimal effect, if any, on enzymatic cellulose conversion. Furthermore, this result, coupled with significant calcium levels in the isolated lignins, supports previous work suggesting lignin-calcium complexes reduce enzyme......Lignins were enzymatically isolated from corn stover and wheat straw samples and subjected to hydrothermal or wet oxidation pretreatments for enzyme adsorption experimentations. Lignin contents of the isolates ranged from 26 to 71 % (w/w); cellulose ranged from 3 to 22 % (w/w); xylan from 0.7 to 6...

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

    International Nuclear Information System (INIS)

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

    2012-01-01

    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 O 2 . − 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.

  10. Coconut coir pith lignin: A physicochemical and thermal characterization.

    Science.gov (United States)

    Asoka Panamgama, L; Peramune, P R U S K

    2018-07-01

    The structural and thermal features of coconut coir pith lignin, isolated by three different extraction protocols incorporating two different energy supply sources, were characterized by different analytical tools. The three different chemical extraction protocols were alkaline - 7.5% (w/v) NaOH, organosolv - 85% (v/v) formic and acetic acids at 7:3 (v/v) ratio and polyethylene glycol (PEG): water ratio at 80:20wt%. The two sources of energy were thermal or microwave. Raw lignins were modified by epichlorohydrin to enhance reactivity, and the characteristics of raw and modified lignins were comparatively analysed. Using the thermal energy source, the alkaline and organosolv processes obtained the highest and lowest lignin yields of 26.4±1.5wt% and 3.4±0.2wt%, respectively, as shown by wet chemical analysis. Specific functional group analysis by Fourier transform infrared spectra (FTIR) revealed that significantly different amounts of hydroxyl and carbonyl groups exist in alkaline, organosolv and PEG lignins. Thermogravimetric analysis (TGA) illustrated that the lowest degradation onset temperature was recorded for organosolv lignin, and the overall order was organosolvlignin extraction from coir pith can be performed efficiently with several protocols and that those methods offer practical value to industry. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Study of lignin biotransformation by Aspergillus fumigatus and white-rot fungi using 14C-labeled and unlabeled kraft lignins

    International Nuclear Information System (INIS)

    Kadam, K.K.; Drew, S.W.

    1986-01-01

    The biodegradation of lignin by fungi was studied in shake flasks using 14 C-labeled kraft lignin and in a deep-tank fermentor using unlabeled kraft lignin. Among the fungi screened, A. fumigatus - isolated in our laboratories - was most potent in lignin biotransformation. Dialysis-type fermentation, designed to study possible accumulation of low MW lignin-derived products, showed no such accumulation. Recalcitrant carbohydrates like microcrystalline cellulose supported higher lignolytic activity than easily metabolized carbohydrates like cellobiose. An assay developed to distinguish between CO 2 evolved from lignin and carbohydrate substrates demonstrated no stoichiometric correlation between the metabolism of the two cosubstrates. The submerged fermentations with unlabeled liqnin are difficult to monitor since chemical assays do not give accurate and true results. Lignolytic efficiencies that allowed monitoring of such fermentations were defined. Degraded lignins were clearly superior to C. versicolor in all aspects of lignin degradation; A fumigatus brought about substantial demethoxylation and dehydroxylation, whereas C. versicolor degraded lignins closely resembled undegraded kraft lignin. There was a good agreement among the different indices of lignin degradation, namely, 14 CO evolution, OCH 3 loss, OH loss, and monomer and dimer yield after permanganate oxidation

  12. Insulin Biosynthetic Interaction Network Component, TMEM24, Facilitates Insulin Reserve Pool Release

    Directory of Open Access Journals (Sweden)

    Anita Pottekat

    2013-09-01

    Full Text Available Insulin homeostasis in pancreatic β cells is now recognized as a critical element in the progression of obesity and type II diabetes (T2D. Proteins that interact with insulin to direct its sequential synthesis, folding, trafficking, and packaging into reserve granules in order to manage release in response to elevated glucose remain largely unknown. Using a conformation-based approach combined with mass spectrometry, we have generated the insulin biosynthetic interaction network (insulin BIN, a proteomic roadmap in the β cell that describes the sequential interacting partners of insulin along the secretory axis. The insulin BIN revealed an abundant C2 domain-containing transmembrane protein 24 (TMEM24 that manages glucose-stimulated insulin secretion from a reserve pool of granules, a critical event impaired in patients with T2D. The identification of TMEM24 in the context of a comprehensive set of sequential insulin-binding partners provides a molecular description of the insulin secretory pathway in β cells.

  13. Accumulation of Kaempferitrin and Expression of Phenyl-Propanoid Biosynthetic Genes in Kenaf (Hibiscus cannabinus

    Directory of Open Access Journals (Sweden)

    Shicheng Zhao

    2014-10-01

    Full Text Available Kenaf (Hibiscus cannabinus is cultivated worldwide for its fiber; however, the medicinal properties of this plant are currently attracting increasing attention. In this study, we investigated the expression levels of genes involved in the biosynthesis of kaempferitrin, a compound with many biological functions, in different kenaf organs. We found that phenylalanine ammonia lyase (HcPAL was more highly expressed in stems than in other organs. Expression levels of cinnamate 4-hydroxylase (HcC4H and 4-coumarate-CoA ligase (Hc4CL were highest in mature leaves, followed by stems and young leaves, and lowest in roots and mature flowers. The expression of chalcone synthase (HcCHS, chalcone isomerase (HcCHI, and flavone 3-hydroxylase (HcF3H was highest in young flowers, whereas that of flavone synthase (HcFLS was highest in leaves. An analysis of kaempferitrin accumulation in the different organs of kenaf revealed that the accumulation of this compound was considerably higher (>10-fold in leaves than in other organs. On the basis of a comparison of kaempferitrin contents with the expression levels of different genes in different organs, we speculate that HcFLS plays an important regulatory role in the kaempferitrin biosynthetic pathway in kenaf.

  14. Accumulation of kaempferitrin and expression of phenyl-propanoid biosynthetic genes in kenaf (Hibiscus cannabinus).

    Science.gov (United States)

    Zhao, Shicheng; Li, Xiaohua; Cho, Dong Ha; Arasu, Mariadhas Valan; Al-Dhabi, Naif Abdullah; Park, Sang Un

    2014-10-23

    Kenaf (Hibiscus cannabinus) is cultivated worldwide for its fiber; however, the medicinal properties of this plant are currently attracting increasing attention. In this study, we investigated the expression levels of genes involved in the biosynthesis of kaempferitrin, a compound with many biological functions, in different kenaf organs. We found that phenylalanine ammonia lyase (HcPAL) was more highly expressed in stems than in other organs. Expression levels of cinnamate 4-hydroxylase (HcC4H) and 4-coumarate-CoA ligase (Hc4CL) were highest in mature leaves, followed by stems and young leaves, and lowest in roots and mature flowers. The expression of chalcone synthase (HcCHS), chalcone isomerase (HcCHI), and flavone 3-hydroxylase (HcF3H) was highest in young flowers, whereas that of flavone synthase (HcFLS) was highest in leaves. An analysis of kaempferitrin accumulation in the different organs of kenaf revealed that the accumulation of this compound was considerably higher (>10-fold) in leaves than in other organs. On the basis of a comparison of kaempferitrin contents with the expression levels of different genes in different organs, we speculate that HcFLS plays an important regulatory role in the kaempferitrin biosynthetic pathway in kenaf.

  15. Kaempferol increases levels of coenzyme Q in kidney cells and serves as a biosynthetic ring precursor.

    Science.gov (United States)

    Fernández-Del-Río, Lucía; Nag, Anish; Gutiérrez Casado, Elena; Ariza, Julia; Awad, Agape M; Joseph, Akil I; Kwon, Ohyun; Verdin, Eric; de Cabo, Rafael; Schneider, Claus; Torres, Jorge Z; Burón, María I; Clarke, Catherine F; Villalba, José M

    2017-09-01

    Coenzyme Q (Q) is a lipid-soluble antioxidant essential in cellular physiology. Patients with Q deficiencies, with few exceptions, seldom respond to treatment. Current therapies rely on dietary supplementation with Q 10 , but due to its highly lipophilic nature, Q 10 is difficult to absorb by tissues and cells. Plant polyphenols, present in the human diet, are redox active and modulate numerous cellular pathways. In the present study, we tested whether treatment with polyphenols affected the content or biosynthesis of Q. Mouse kidney proximal tubule epithelial (Tkpts) cells and human embryonic kidney cells 293 (HEK 293) were treated with several types of polyphenols, and kaempferol produced the largest increase in Q levels. Experiments with stable isotope 13 C-labeled kaempferol demonstrated a previously unrecognized role of kaempferol as an aromatic ring precursor in Q biosynthesis. Investigations of the structure-function relationship of related flavonols showed the importance of two hydroxyl groups, located at C3 of the C ring and C4' of the B ring, both present in kaempferol, as important determinants of kaempferol as a Q biosynthetic precursor. Concurrently, through a mechanism not related to the enhancement of Q biosynthesis, kaempferol also augmented mitochondrial localization of Sirt3. The role of kaempferol as a precursor that increases Q levels, combined with its ability to upregulate Sirt3, identify kaempferol as a potential candidate in the design of interventions aimed on increasing endogenous Q biosynthesis, particularly in kidney. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. The synthesis of chlorophyll-a biosynthetic precursors and methyl substituted iron porphyrins

    International Nuclear Information System (INIS)

    Matera, K.M.

    1988-01-01

    The biosynthetic intermediates were incubated in a plant system. The activity levels calculated show that magnesium 6-acrylate porphyrins and one of the magnesium 6-β-hydroxypropionate porphyrins are not intermediates. In addition, plant systems incubated with 18 O 2 were found to synthesize magnesium 2,4-divinyl pheoporphyrin-a 5 incorporated with 18 O at the 9-carbonyl oxygen. Mass spectroscopy confirmed the presence of the oxygen label, thus eliminating one of two hypothesized pathways to chlorophyll-a. An overall description is given of iron porphyrins and iron porphyrin containing proteins. The function of the propionic side chains of the heme prosthetic group during electron transport reactions will be investigated. The synthesis of a series of iron(III) hexamethyl porphyrins with increasingly longer substituents in the remaining two peripheral positions of the porphyrin is described. Models for NMR studies of iron chlorin containing enzymes are discussed. Iron(III) pyropheophorbide-a and methyl pyropheophorbide-a were synthesized in addition to 5-CD 3 , 10-CD 2 iron(III) pyropheophorbide-a and methyl pyropheophorbide-a. Together, these pyropheophorbides were used to assign NMR resonances and ultimately provide a model for other iron chlorins. The synthesis of nickel(II) anhydro-mesorhodoporphyrin from zinc(III) anhydromesorhodochlorin is described; this nickel porphyrin was used as a standard for ring current calculations of reduced nickel analogs of anhydromesorhodoporphyrin

  17. Sequence diversity and differential expression of major phenylpropanoid-flavonoid biosynthetic genes among three mango varieties.

    Science.gov (United States)

    Hoang, Van L T; Innes, David J; Shaw, P Nicholas; Monteith, Gregory R; Gidley, Michael J; Dietzgen, Ralf G

    2015-07-30

    Mango fruits contain a broad spectrum of phenolic compounds which impart potential health benefits; their biosynthesis is catalysed by enzymes in the phenylpropanoid-flavonoid (PF) pathway. The aim of this study was to reveal the variability in genes involved in the PF pathway in three different mango varieties Mangifera indica L., a member of the family Anacardiaceae: Kensington Pride (KP), Irwin (IW) and Nam Doc Mai (NDM) and to determine associations with gene expression and mango flavonoid profiles. A close evolutionary relationship between mango genes and those from the woody species poplar of the Salicaceae family (Populus trichocarpa) and grape of the Vitaceae family (Vitis vinifera), was revealed through phylogenetic analysis of PF pathway genes. We discovered 145 SNPs in total within coding sequences with an average frequency of one SNP every 316 bp. Variety IW had the highest SNP frequency (one SNP every 258 bp) while KP and NDM had similar frequencies (one SNP every 369 bp and 360 bp, respectively). The position in the PF pathway appeared to influence the extent of genetic diversity of the encoded enzymes. The entry point enzymes phenylalanine lyase (PAL), cinnamate 4-mono-oxygenase (C4H) and chalcone synthase (CHS) had low levels of SNP diversity in their coding sequences, whereas anthocyanidin reductase (ANR) showed the highest SNP frequency followed by flavonoid 3'-hydroxylase (F3'H). Quantitative PCR revealed characteristic patterns of gene expression that differed between mango peel and flesh, and between varieties. The combination of mango expressed sequence tags and availability of well-established reference PF biosynthetic genes from other plant species allowed the identification of coding sequences of genes that may lead to the formation of important flavonoid compounds in mango fruits and facilitated characterisation of single nucleotide polymorphisms between varieties. We discovered an association between the extent of sequence variation and

  18. NMR characterization of lignins isolated from fruit and vegetable insoluble dietary fiber.

    Science.gov (United States)

    Bunzel, Mirko; Ralph, John

    2006-10-18

    Compositional information for lignins in food is rare and concentrated on cereal grains and brans. As lignins are suspected to have important health roles in the dietary fiber complex, the confusing current information derived from nonspecific lignin determination methods needs to be augmented by diagnostic structural studies. For this study, lignin fractions were isolated from kiwi, pear, rhubarb, and, for comparison, wheat bran insoluble dietary fiber. Clean pear and kiwi lignin isolates allowed for substantive structural profiling, but it is suggested that the significance of lignin in wheat has been overestimated by reliance on nonspecific analytical methods. Volume integration of NMR contours in two-dimensional (13)C-(1)H correlation spectra shows that pear and wheat lignins have comparable guaiacyl and syringyl contributions and that kiwi lignins are particularly guaiacyl-rich (approximately 94% guaiacyl) and suggest that rhubarb lignins, which could not be isolated from contaminating materials, are as syringyl-rich (approximately 96% syringyl) as lignins from any known natural or transgenic fiber source. Typical lignin structures, including those newly NMR-validated (glycerols, spirodienones, and dibenzodioxocins), and resinols implicated as possible mammalian lignan precursors in the gut are demonstrated via their NMR correlation spectra in the fruit and vegetable samples. A novel putative benzodioxane structure appears to be associated with the kiwi lignin. It is concluded that the fruits and vegetables examined contain authentic lignins and that the detailed structural analysis exposes limitations of currently accepted analytical methods.

  19. Preparation of lignin-based carbon aerogels as biomaterials for nano-supercapacitor

    Science.gov (United States)

    Yang, Bong Suk; Kang, Kyu-Young; Jeong, Myung-Joon

    2017-10-01

    Kraft and organosolv lignins, generally produced in chemical pulping and bio-refinery processes of lignocellulosic biomass, were used to prepare lignin-based carbon aerogels for supercapacitors as raw materials. The difference between lignins and lignin-based aerogels were compared by analyzing physical and chemical properties, including molecular weight, polydispersity, and reactivity with formaldehyde. Also, density, shrinkage, Brunauer-Emmett-Teller (BET) surface area and scanning electron microscope (SEM) images of the lignin-based aerogel were investigated. Kraft lignin consisting of coniferyl alcohol (G) and p-coumaryl alcohol (H) increased the reactivity of formaldehyde, formed a hydrogel well (porosity > 0.45), and specific surface area higher than organosolv lignin. In the case of kraft lignin, there were irregular changes such as oxidation and condensation in the pulping process. However, reaction sites with aromatic rings in lignin impacted the production of aerogel and required a long gelation period. The molecular weight of lignin influences the gelation time in producing lignin-based aerogel, and lignin composition affects the BET surface area and pore structures of the lignin-based carbon aerogels.

  20. Effect of lignin chemistry on the enzymatic hydrolysis of woody biomass.

    Science.gov (United States)

    Yu, Zhiying; Gwak, Ki-Seob; Treasure, Trevor; Jameel, Hasan; Chang, Hou-min; Park, Sunkyu

    2014-07-01

    The impact of lignin-derived inhibition on enzymatic hydrolysis is investigated by using lignins isolated from untreated woods and pretreated wood pulps. A new method, biomass reconstruction, for which isolated lignins are precipitated onto bleached pulps to mimic lignocellulosic biomass, is introduced, for the first time, to decouple the lignin distribution issue from lignin chemistry. Isolated lignins are physically mixed and reconstructed with bleached pulps. Lignins obtained from pretreated woods adsorb two to six times more cellulase than lignins obtained from untreated woods. The higher adsorption of enzymes on lignin correlates with decreased carbohydrate conversion in enzymatic hydrolysis. In addition, the reconstructed softwood substrate has a lower carbohydrate conversion than the reconstructed hardwood substrate. The degree of condensation of lignin increases significantly after pretreatment, especially with softwood lignins. In this study, the degree of condensation of lignin (0.02 to 0.64) and total OH groups in lignin (1.7 to 1.1) have a critical impact on cellulase adsorption (9 to 70%) and enzymatic hydrolysis (83.2 to 58.2%); this may provide insights into the more recalcitrant nature of softwood substrates. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Isolation and characterization of new lignin streams derived from extractive-ammonia (EA) pretreatment

    Energy Technology Data Exchange (ETDEWEB)

    da Costa Sousa, Leonardo [Michigan State Univ., East Lansing, MI (United States); Foston, Marcus [Washington Univ., St. Louis, MO (United States); Bokade, Vijay [National Chemical Lab., Pune (India); Azarpira, Ali [Univ. of Wisconsin, Madison, WI (United States); Lu, Fachuang [Univ. of Wisconsin, Madison, WI (United States); Ragauskas, Arthur J. [Univ. of Tennessee, Knoxville, TN (United States); Ralph, John [Univ. of Wisconsin, Madison, WI (United States); Dale, Bruce [Michigan State Univ., East Lansing, MI (United States); Balan, Venkatesh [Michigan State Univ., East Lansing, MI (United States)

    2016-05-05

    One of the key challenges facing lignin conversion to fuels and chemicals is related to the level of carbohydrate and ash impurities found in extracted lignin. Structural modifications of lignin may also occur as a result of biomass pretreatment and harsh lignin extraction protocols. Extractive-Ammonia (EA) is a new pretreatment technology that uses liquid ammonia to cleave lignin–carbohydrate complexes, decrystallize cellulose, solubilize lignin, and selectively extract lignin from lignocellulosic biomass, enabling better utilization of both lignin and carbohydrate components in a biorefinery. The EA-based biorefinery produces two different lignin-rich streams, with different properties, that could potentially be upgraded to fuels and chemicals using green processes. Here, a water/ethanol-based fractionation method was developed to enrich the ammonia-soluble extractives, resulting in a major product stream containing 92% lignin. Detailed characterization of the various streams resulting from EA treatment, including compositional analysis, structural characterization by nuclear magnetic resonance (NMR) spectrometry, elemental analysis, molecular weight analysis, and thermo-gravimetric analysis provides a broad evaluation of the EA-derived lignin product stream structures and properties, assessing their potential for commercial applications. In conclusion, EA-derived lignins preserve much of lignin's functionality, including the sensitive β-aryl ether units. Furthermore, we observed nitrogen incorporation in the lignin-rich streams, notably due to the presence of hydroxycinnamoyl amides formed during ammonia pretreatment.

  2. Polymorphisms in monolignol biosynthetic genes are associated with biomass yield and agronomic traits in European maize (Zea mays L.)

    DEFF Research Database (Denmark)

    Chen, Yongsheng; Zein, Imad; Brenner, Everton A

    2010-01-01

    Background Reduced lignin content leads to higher cell wall digestibility and, therefore, better forage quality and increased conversion of lignocellulosic biomass into ethanol. However, reduced lignin content might lead to weaker stalks, lodging, and reduced biomass yield. Genes encoding enzymes...

  3. Possible Interactions between the Biosynthetic Pathways of Indole Glucosinolate and Auxin

    Directory of Open Access Journals (Sweden)

    Siva K. Malka

    2017-12-01

    Full Text Available Glucosinolates (GLS are a group of plant secondary metabolites mainly found in Cruciferous plants, share a core structure consisting of a β-thioglucose moiety and a sulfonated oxime, but differ by a variable side chain derived from one of the several amino acids. These compounds are hydrolyzed upon cell damage by thioglucosidase (myrosinase, and the resulting degradation products are toxic to many pathogens and herbivores. Human beings use these compounds as flavor compounds, anti-carcinogens, and bio-pesticides. GLS metabolism is complexly linked to auxin homeostasis. Indole GLS contributes to auxin biosynthesis via metabolic intermediates indole-3-acetaldoxime (IAOx and indole-3-acetonitrile (IAN. IAOx is proposed to be a metabolic branch point for biosynthesis of indole GLS, IAA, and camalexin. Interruption of metabolic channeling of IAOx into indole GLS leads to high-auxin production in GLS mutants. IAN is also produced as a hydrolyzed product of indole GLS and metabolized to IAA by nitrilases. In this review, we will discuss current knowledge on involvement of GLS in auxin homeostasis.

  4. Assembly of a novel biosynthetic pathway for production of the plant flavonoid fisetin in Escherichia coli

    DEFF Research Database (Denmark)

    Stahlhut, Steen Gustav; Siedler, Solvej; Malla, Sailesh

    2015-01-01

    Plant secondary metabolites are an underutilized pool of bioactive molecules for applications in the food, pharma and nutritional industries. One such molecule is fisetin, which is present in many fruits and vegetables and has several potential health benefits, including anti-cancer, anti-viral a...

  5. Elucidation of the Vanillin Biosynthetic Pathway in Vanilla planifolia

    DEFF Research Database (Denmark)

    Gallage, Nethaji Janeshawari

    peptide is transported into the vacuole for potential degradation (Chapter 3 – Manuscript in preparation). This PhD thesis also includes a review (Chapter 4), which represents the current state of biotechnology-derived vanillin synthesis based on ferulic acid, eugenol and glucose using microorganisms....... Vanillin is a compound of major interest in the flavour and fragrance industry. In 2010, the annual world sales of vanillin reached more than 15,000 tons, Nowadays, less than 1 % of the global production of vanillin is derived from vanilla pods, since the production and isolation of vanillin from vanilla...... discovery and downstream processing methods due to physicochemical properties of the substrate, the product and the nature of microorganisms used. Hence, bioengineering tools have been employed to circumvent these drawbacks. The review emphasizes the major issues encountered and the solutions obtained...

  6. Ethylene and 1-MCP regulate major volatile biosynthetic pathways in apple fruit.

    Science.gov (United States)

    Yang, Xiaotang; Song, Jun; Du, Lina; Forney, Charles; Campbell-Palmer, Leslie; Fillmore, Sherry; Wismer, Paul; Zhang, Zhaoqi

    2016-03-01

    The effects of ethylene and 1-methylcyclopropene (1-MCP) on apple fruit volatile biosynthesis and gene expression were investigated. Statistical analysis identified 17 genes that changed significantly in response to ethylene and 1-MCP treatments. Genes encoding branched-chain amino acid aminotransferase (BCAT), aromatic amino acid aminotransferase (ArAT) and amino acid decarboxylases (AADC) were up-regulated during ripening and further enhanced by ethylene treatment. Genes related to fatty acid synthesis and metabolism, including acyl-carrier-proteins (ACPs), malonyl-CoA:ACP transacylase (MCAT), acyl-ACP-desaturase (ACPD), lipoxygenase (LOX), hydroperoxide lyase (HPL), alcohol dehydrogenase (ADH), pyruvate decarboxylase (PDC2), β-oxidation, acyl-CoA synthetase (ACS), enoyl-CoA hydratase (ECHD), acyl-CoA dehydrogenase (ACAD), and alcohol acyltransferases (AATs) also increased during ripening and in response to ethylene treatment. Allene oxide synthase (AOS), alcohol dehydrogenase 1 (ADH1), 3-ketoacyl-CoA thiolase and branched-chain amino acid aminotransferase 2 (BCAT2) decreased in ethylene-treated fruit. Treatment with 1-MCP and ethylene generally produced opposite effects on related genes, which provides evidence that regulation of these genes is ethylene dependent. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  7. Examination of Triacylglycerol Biosynthetic Pathways via De Novo Transcriptomic and Proteomic Analyses in an Unsequenced Microalga

    Science.gov (United States)

    2011-10-17

    and none of the TAG enzymatic components. Conversely , utilization of the C. vulgaris transcriptome as a search database allowed us to identify all...for conversion to biodiesel or renewable diesel and jet fuel [1,2,3]. Many of these species can also grow rapidly under a large range of environmental...overnight. Approximately 5 mg of dry biomass was suspended in chloroform-methanol (2:1, v/v), and glyceroli- pids were transesterified in HCl-methanol (5

  8. Metabolic engineering of the Stevia rebaudiana ent-kaurene biosynthetic pathway in recombinant Escherichia coli.

    Science.gov (United States)

    Kong, Min Kyung; Kang, Hyun-Jun; Kim, Jin Ho; Oh, Soon Hwan; Lee, Pyung Cheon

    2015-11-20

    The ent-kaurene is a dedicated precursor pool and is responsible for synthesizing natural sweeteners such as steviol glycosides. In this study, to produce ent-kaurene in Escherichia coli, we modularly constructed and expressed two ent-kaurene genes encoding ent-copalyl diphosphate synthase (CPPS) and ent-kaurene synthase (KS) from Stevia rebaudiana known as a typical plant producing steviol glycoside. The CPPS and KS from S. rebaudiana were functionally expressed in a heterologous host E. coli. Furthermore, in order to enhance ent-kaurene production in E. coli, six geranylgeranyl diphosphate synthases (GGPPS) from various microorganisms and eight strains of E. coli as host were compared by measuring ent-kaurene production. The highest ent-kaurene production of approximately 41.1mg/L was demonstrated in E. coli strain MG1655 co-expressing synthetic CPPS-KS module and GGPPS from Rhodobacter sphaeroides. The ent-kaurene production was further increased up to 179.6 mg/L by overexpression of the three key enzymes for isoprenoid precursor, 1-deoxyxylulose-5-phosphate synthase (DXS), farnesyl diphosphate synthase (IspA) and isopentenyl diphosphate isomerase (IDI) from E. coli. Finally, the highest titer of ent-kaurene (578 mg/L) with a specific yield of ent-kaurene of 143.5mg/g dry cell weight was obtained by culturing E. coli strain MG1655 co-expressing the ent-kaurene module, DXS, IDI and IspA in 1L bioreactor containing 20 g/L glycerol. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Elucidation of the sesquiterpene lactone biosynthetic pathway in feverfew (Tanacetum parthenium)

    OpenAIRE

    Liu, Q.

    2013-01-01

    Parthenolide is the major bioactive compound of feverfew and has anti-inflammatory and anti-cancer activity. Chapter 1gives an overview of the history and current status of research on parthenolide in feverfew. As a promising anti-cancer drug, parthenolide has attracted a lot of attention from medical institutes and companies. A search with ‘parthenolide’ in Google patents yields more than 2000 hits on extraction of parthenolide or its use in treating cancer or other diseases. However, infor...

  10. Improving the nutritional of tomatoes through reprogramming their flavonoid biosynthetic pathway

    NARCIS (Netherlands)

    Colliver, S.; Bovy, A.; Collins, G.; Muir, S.; Robinson, S.; Vos, de C.H.R.; Verhoeyen, M.E.

    2002-01-01

    Flavonoids are a diverse group of phenolic secondary metabolites that occur naturally in plants and therefore form an integral component of the human diet. Many of the compounds belonging to this group are potent antioxidants in vitro and epidemiological studies suggest a direct correlation between

  11. Increasing antioxidant levels in tomatoes through modification of the flavonoid biosynthetic pathway

    NARCIS (Netherlands)

    Verhoeyen, M.E.; Bovy, A.; Collins, G.; Muir, S.; Vos Robinson, S.; Vos, de C.H.R.; Colliver, S.

    2002-01-01

    Flavonoids are a diverse group of phenolic secondary metabolites that occur naturally in plants and therefore form an integral component of the human diet. Many of the compounds belonging to this group are potent antioxidants in vitro and epidemiological studies suggest a direct correlation between

  12. Engineering the provitamin A (beta-carotene) biosynthetic pathway into (carotenoid-free) rice endosperm.

    Science.gov (United States)

    Ye, X; Al-Babili, S; Klöti, A; Zhang, J; Lucca, P; Beyer, P; Potrykus, I

    2000-01-14

    Rice (Oryza sativa), a major staple food, is usually milled to remove the oil-rich aleurone layer that turns rancid upon storage, especially in tropical areas. The remaining edible part of rice grains, the endosperm, lacks several essential nutrients, such as provitamin A. Thus, predominant rice consumption promotes vitamin A deficiency, a serious public health problem in at least 26 countries, including highly populated areas of Asia, Africa, and Latin America. Recombinant DNA technology was used to improve its nutritional value in this respect. A combination of transgenes enabled biosynthesis of provitamin A in the endosperm.

  13. A Unique Tryptophan C-Prenyltransferase from the Kawaguchipeptin Biosynthetic Pathway

    Czech Academy of Sciences Publication Activity Database

    Parajuli, A.; Kwak, D.H.; Dalponte, L.; Leikoski, N.; Galica, Tomáš; Umeobika, U.; Trembleau, L.; Sivonen, K.; Wahlsten, M.; Wang, H.; Rizzi, E.; De Bellis, G.; Naismith, J.; Jaspars, M.; Liu, X.Y.; Houssen, W.; Fewer, D.P.

    2016-01-01

    Roč. 55, č. 11 (2016), s. 3596-3599 ISSN 1433-7851 R&D Projects: GA MŠk(CZ) LO1416 Institutional support: RVO:61388971 Keywords : biosynthesis * cyanobactins * peptides Subject RIV: EE - Microbiology, Virology Impact factor: 11.994, year: 2016

  14. Elucidation of the sesquiterpene lactone biosynthetic pathway in feverfew (Tanacetum parthenium)

    NARCIS (Netherlands)

    Liu, Q.

    2013-01-01

    Parthenolide is the major bioactive compound of feverfew and has anti-inflammatory and anti-cancer activity. Chapter 1gives an overview of the history and current status of research on parthenolide in feverfew. As a promising anti-cancer drug, parthenolide has attracted a lot of

  15. Exploring triacylglycerol biosynthetic pathway in developing seeds of Chia (Salvia hispanica L.: a transcriptomic approach.

    Directory of Open Access Journals (Sweden)

    Sreedhar R V

    Full Text Available Chia (Salvia hispanica L., a member of the mint family (Lamiaceae, is a rediscovered crop with great importance in health and nutrition and is also the highest known terrestrial plant source of heart-healthy omega-3 fatty acid, alpha linolenic acid (ALA. At present, there is no public genomic information or database available for this crop, hindering research on its genetic improvement through genomics-assisted breeding programs. The first comprehensive analysis of the global transcriptome profile of developing Salvia hispanica L. seeds, with special reference to lipid biosynthesis is presented in this study. RNA from five different stages of seed development was extracted and sequenced separately using the Illumina GAIIx platform. De novo assembly of processed reads in the pooled transcriptome using Trinity yielded 76,014 transcripts. The total transcript length was 66,944,462 bases (66.9 Mb, with an average length of approximately 880 bases. In the molecular functions category of Gene Ontology (GO terms, ATP binding and nucleotide binding were found to be the most abundant and in the biological processes category, the metabolic process and the regulation of transcription-DNA-dependent and oxidation-reduction process were abundant. From the EuKaryotic Orthologous Groups of proteins (KOG classification, the major category was "Metabolism" (31.97%, of which the most prominent class was 'carbohydrate metabolism and transport' (5.81% of total KOG classifications followed by 'secondary metabolite biosynthesis transport and catabolism' (5.34% and 'lipid metabolism' (4.57%. A majority of the candidate genes involved in lipid biosynthesis and oil accumulation were identified. Furthermore, 5596 simple sequence repeats (SSRs were identified. The transcriptome data was further validated through confirmative PCR and qRT-PCR for select lipid genes. Our study provides insight into the complex transcriptome and will contribute to further genome-wide research and understanding of chia. The identified novel UniGenes will facilitate gene discovery and creation of genomic resource for this crop.

  16. Exploring Triacylglycerol Biosynthetic Pathway in Developing Seeds of Chia (Salvia hispanica L.): A Transcriptomic Approach

    OpenAIRE

    R. V., Sreedhar; Kumari, Priya; Rupwate, Sunny D.; Rajasekharan, Ram; Srinivasan, Malathi

    2015-01-01

    Chia (Salvia hispanica L.), a member of the mint family (Lamiaceae), is a rediscovered crop with great importance in health and nutrition and is also the highest known terrestrial plant source of heart-healthy omega-3 fatty acid, alpha linolenic acid (ALA). At present, there is no public genomic information or database available for this crop, hindering research on its genetic improvement through genomics-assisted breeding programs. The first comprehensive analysis of the global transcriptome...

  17. Imaging of Enzymes in the Steroid Biosynthetic Pathway: Synthesis of 18F-Labelled Tracers

    International Nuclear Information System (INIS)

    Erlandsson, Maria

    2009-01-01

    This thesis deals with the synthesis and development of 18 F-labelled alkyl etomidate and vorozole analogues, and their use as positron emission tomography (PET) tracers for the imaging of the steroid enzymes 11β-hydroxylase and aromatase. Two synthetic 18 F-labelling approaches to the etomidate and vorozole analogues were developed, and the analogues were evaluated in some biological assays. The two-step labelling method was used to synthesise many compounds for biological evaluation. In the first step, a 18 F-labelled intermediate based on a ditosylate or a halogenated diethyl ether was synthesised and used directly in the next alkylation step. The decay-corrected (d.c.) radiochemical yield was higher compared to other known two-step labelling methods. Once an appropriate candidate has been chosen for clinical evaluation, a one-step labelling method will be more suitable. We therefore developed a method based on precursors that had leaving groups at the end of their alkyl chains, and used these directly in the 18 F-labelling synthesis. The one-step 18 F-labelling synthesis required less reaction time and produced higher specific radioactivity and d.c. radiochemical yield than our two-step synthesis. With microwave heating, the reaction time was reduced to seconds and the d.c. radiochemical yield was better than that obtained with conventional heating. The one-step synthesis simplified the technical handling by allowing the tracer syntheses to be automated on the TRACERLab FX FN

  18. Genomic Wake-Up Call : Activating Silent Biosynthetic Pathways for Novel Metabolites in Penicillium chrysogenum

    NARCIS (Netherlands)

    Samol, Marta

    2015-01-01

    Verborgen schatten in het DNA van Penicillium chrysogenum De draadschimmel Penicillium chrysogenum werd in 1928 door Alexander Fleming ontdekt en wordt veel gebruikt in de industrie voor de productie van β-lactam antibiotica. Antibiotica en andere natuurlijke producten (secundaire metabolieten)

  19. Evidence for Importance of tRNA-dependent Cytokinin Biosynthetic Pathway in the Moss Physcomitrella patens

    Czech Academy of Sciences Publication Activity Database

    Yevdakova, N.A.; Motyka, Václav; Malbeck, Jiří; Trávníčková, Alena; Novák, Ondřej; Strnad, Miroslav; von Schwartzenberg, K.

    2008-01-01

    Roč. 27, č. 3 (2008), s. 271-281 ISSN 0721-7595 R&D Projects: GA MŠk(CZ) LC06034; GA ČR GA206/05/0894; GA AV ČR IAA600380701 Institutional research plan: CEZ:AV0Z50380511 Keywords : Physcomitrella * ove mutant * Cytokinin biosynthesis * tRNA-isopentenyl transferase Subject RIV: ED - Physiology Impact factor: 2.109, year: 2008

  20. Leveraging microbial biosynthetic pathways for the generation of 'drop-in' biofuels

    DEFF Research Database (Denmark)

    Zargar, Amin; Bailey, Constance B.; Haushalter, Robert W.

    2017-01-01

    Advances in retooling microorganisms have enabled bioproduction of 'drop-in' biofuels, fuels that are compatible with existing spark-ignition, compression-ignition, and gas-turbine engines. As the majority of petroleum consumption in the United States consists of gasoline (47%), diesel fuel...... acid, terpene, and polyketide synthases for the production of bio-based gasoline, diesel and jet fuel....