The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform
David G J Mann - One of the best experts on this subject based on the ideXlab platform.
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identification and overexpression of gibberellin 2 oxidase ga2ox in switchgrass panicum virgatum l for improved plant architecture and reduced biomass recalcitrance
Plant Biotechnology Journal, 2015Co-Authors: Mitra Mazarei, Wegi A Wuddineh, Jiyi Zhang, Charleson R Poovaiah, David G J Mann, Angela ZiebellAbstract:Gibberellin 2-oxidases (GA2oxs) are a group of 2-oxoglutarate-dependent dioxygenases that catalyse the deactivation of bioactive GA or its precursors through 2β-hydroxylation reaction. In this study, putatively novel switchgrass C20 GA2ox genes were identified with the aim of genetically engineering switchgrass for improved architecture and reduced biomass recalcitrance for biofuel. Three C20 GA2ox genes showed differential regulation patterns among tissues including roots, seedlings and reproductive parts. Using a transgenic approach, we showed that overexpression of two C20 GA2ox genes, that is PvGA2ox5 and PvGA2ox9, resulted in characteristic GA-deficient phenotypes with dark-green leaves and modified plant architecture. The changes in plant morphology appeared to be associated with GA2ox transcript abundance. Exogenous application of GA rescued the GA-deficient phenotypes in transgenic lines. Transgenic semi-dwarf lines displayed increased tillering and reduced Lignin content, and the syringyl/Guaiacyl Lignin monomer ratio accompanied by the reduced expression of Lignin biosynthetic genes compared to nontransgenic plants. A moderate increase in the level of glucose release in these transgenic lines might be attributed to reduced biomass recalcitrance as a result of reduced Lignin content and Lignin composition. Our results suggest that overexpression of GA2ox genes in switchgrass is a feasible strategy to improve plant architecture and reduce biomass recalcitrance for biofuel.
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two year field analysis of reduced recalcitrance transgenic switchgrass
Plant Biotechnology Journal, 2014Co-Authors: Mitra Mazarei, Holly L Baxter, David G J Mann, Nicole Labbe, Lindsey M Kline, Qunkang Cheng, Mark T WindhamAbstract:Summary Switchgrass (Panicum virgatum L.) is a leading candidate for a dedicated lignocellulosic biofuel feedstock owing to its high biomass production, wide adaptation and low agronomic input requirements. Lignin in cell walls of switchgrass, and other lignocellulosic feedstocks, severely limits the accessibility of cell wall carbohydrates to enzymatic breakdown into fermentable sugars and subsequently biofuels. Low-Lignin transgenic switchgrass plants produced by the down-regulation of caffeic acid O-methyltransferase (COMT), a Lignin biosynthetic enzyme, were analysed in the field for two growing seasons. COMT transcript abundance, Lignin content and the syringyl/Guaiacyl Lignin monomer ratio were consistently lower in the COMT-down-regulated plants throughout the duration of the field trial. In general, analyses with fully established plants harvested during the second growing season produced results that were similar to those observed in previous greenhouse studies with these plants. Sugar release was improved by up to 34% and ethanol yield by up to 28% in the transgenic lines relative to controls. Additionally, these results were obtained using senesced plant material harvested at the end of the growing season, compared with the young, green tissue that was used in the greenhouse experiments. Another important finding was that transgenic plants were not more susceptible to rust (Puccinia emaculata). The results of this study suggest that Lignin down-regulation in switchgrass can confer real-world improvements in biofuel yield without negative consequences to biomass yield or disease susceptibility.
Patrick G Hatcher - One of the best experts on this subject based on the ideXlab platform.
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the application of 13c labeled tetramethylammonium hydroxide 13c tmah thermochemolysis to the study of fungal degradation of wood
Organic Geochemistry, 2000Co-Authors: Timothy R Filley, Patrick G Hatcher, W C Shortle, R T PraseuthAbstract:This paper presents the results from an assessment of the application of a new molecular analytical procedure, 13 CTMAH thermochemolysis, to study the chemical modification of Lignin by white-rot and brown-rot fungi. This technique diAers from other molecular chemolysis procedures (e.g. TMAH thermochemolysis and CuO alkaline oxidation) as it enables one to determine the amount of hydroxylated aromatic components in degraded Lignin residues through a selective Lignin depolymerization and 13 C-labeled methylation reaction. Major diAerences were observed in the chemical composition and yield of Lignin monomers released from a limited sample set of field and laboratory inoculation brown-rot and white-rot degraded residues when analyzed by 13 C-TMAH thermochemolysis. The brown-rot residues were characterized by high yields of 3,4-dihydroxy phenyl compounds, presumably due to fungal demethylation of methoxyl groups on Guaiacyl Lignin, and relatively low yields of aromatic acids that result from microbial side chain oxidation. The white-rot residues were characterized by low yields of demethylated Lignin monomers but relatively high yields of monomers exhibiting side chain oxidation. If generally applicable, this distinct chemical functionality has important implications for the chemical reactivity and solubility of degraded wood residues and consequently the cycling of terrestrial carbon in the geosphere. The 13 C-TMAH thermochemolysis procedure provides a rapid and sensitive tool for tracking microbial modifications of Lignin in terrestrial environments including coastal sediments, forest soils and waters receiving terrestrial organic matter. # 2000 Elsevier Science Ltd. All rights reserved.
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tetramethylammonium hydroxide tmah thermochemolysis proposed mechanisms based upon the application of 13c labeled tmah to a synthetic model Lignin dimer
Organic Geochemistry, 1999Co-Authors: R D Minard, Timothy R Filley, Patrick G HatcherAbstract:Abstract The mechanism by which heated tetramethylammonium hydroxide (TMAH) degrades the Lignin biopolymer was investigated by the novel application of 13C-labeled TMAH (13C-TMAH) in the thermochemolysis of a synthetic model Guaiacyl Lignin dimer. GC-MS analysis of the products showed labeling patterns consistent with a base-catalyzed intramolecular displacement of the β-phenoxy group and the formation of two intermediate Guaiacyl propane epoxides, a γ-hydroxy-α,β-epoxide and an α-hydroxy-β,γ-epoxide. Methoxide then functions as a nucleophile to open the epoxide ring. These results substantiate the base-catalyzed reactions previously postulated by Gierer (1970) to explain alkali wood pulping and also explain the facile formation and distribution of Lignin derivatives obtained in the TMAH thermochemolysis of natural samples. The absence of substantial numbers of bonds involving propyl-aryl ether linkages with adjacent hydroxyl groups is the limiting factor in the complete decomposition of Lignin by TMAH thermochemolysis, as propyl-aryl ether linkages without adjacent hydroxyl groups cannot react via this mechanism. This helps to explain why materials such as highly degraded Lignin residues, with significant side chain alteration and type III kerogens above the rank of lignite, where aliphatic-aryl ether linkages are thought to be insignificant, are reported to give low yields of TMAH thermochemolysis products.
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comparison of dehydrogenase polymer dhp Lignin with native Lignin from gymnosperm wood by thermochemolysis using tetramethylammonium hydroxide tmah
Organic Geochemistry, 1996Co-Authors: Patrick G Hatcher, Robert D MinardAbstract:Abstract When analyzed by the TMAH thermochemolysis procedure and solid-state 13C NMR, DHP Guaiacyl Lignin is found to yield products which are somewhat similar to those observed in fresh or degraded gymnosperm Lignin. The relative amounts of the various TMAH products, particularly the stereoisomeric pairs of 3,4-dimethoxyphenyl-trimethoxypropane, however, are not identical, perhaps indicating that disordered and randomly polymerized DHP Lignin is not similar to a possibly more ordered network in natural Lignin.
Mitra Mazarei - One of the best experts on this subject based on the ideXlab platform.
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Functional Analysis of Cellulose Synthase CesA4 and CesA6 Genes in Switchgrass (Panicum virgatum) by Overexpression and RNAi-Mediated Gene Silencing
Frontiers Media S.A., 2018Co-Authors: Mitra Mazarei, Holly L Baxter, Ajaya K. Biswal, Keonhee Kim, Xianzhi MengAbstract:Switchgrass (Panicum virgatum L.) is a leading lignocellulosic bioenergy feedstock. Cellulose is a major component of the plant cell walls and the primary substrate for saccharification. Accessibility of cellulose to enzymatic breakdown into fermentable sugars is limited by the presence of Lignin in the plant cell wall. In this study, putatively novel switchgrass secondary cell wall cellulose synthase PvCesA4 and primary cell wall PvCesA6 genes were identified and their functional role in cellulose synthesis and cell wall composition was examined by overexpression and knockdown of the individual genes in switchgrass. The endogenous expression of PvCesA4 and PvCesA6 genes varied among including roots, leaves, stem, and reproductive tissues. Increasing or decreasing PvCesA4 and PvCesA6 expression to extreme levels in the transgenic lines resulted in decreased biomass production. PvCesA6-overexpressing lines had reduced Lignin content and syringyl/Guaiacyl Lignin monomer ratio accompanied by increased sugar release efficiency, suggesting an impact of PvCesA6 expression levels on Lignin biosynthesis. Cellulose content and cellulose crystallinity were decreased, while xylan content was increased in PvCesA4 and PvCesA6 overexpression or knockdown lines. The increase in xylan content suggests that the amount of non-cellulosic cell wall polysaccharide was modified in these plants. Taken together, the results show that the manipulation of the cellulose synthase genes alters the cell wall composition and availability of cellulose as a bioprocessing substrate
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identification and overexpression of gibberellin 2 oxidase ga2ox in switchgrass panicum virgatum l for improved plant architecture and reduced biomass recalcitrance
Plant Biotechnology Journal, 2015Co-Authors: Mitra Mazarei, Wegi A Wuddineh, Jiyi Zhang, Charleson R Poovaiah, David G J Mann, Angela ZiebellAbstract:Gibberellin 2-oxidases (GA2oxs) are a group of 2-oxoglutarate-dependent dioxygenases that catalyse the deactivation of bioactive GA or its precursors through 2β-hydroxylation reaction. In this study, putatively novel switchgrass C20 GA2ox genes were identified with the aim of genetically engineering switchgrass for improved architecture and reduced biomass recalcitrance for biofuel. Three C20 GA2ox genes showed differential regulation patterns among tissues including roots, seedlings and reproductive parts. Using a transgenic approach, we showed that overexpression of two C20 GA2ox genes, that is PvGA2ox5 and PvGA2ox9, resulted in characteristic GA-deficient phenotypes with dark-green leaves and modified plant architecture. The changes in plant morphology appeared to be associated with GA2ox transcript abundance. Exogenous application of GA rescued the GA-deficient phenotypes in transgenic lines. Transgenic semi-dwarf lines displayed increased tillering and reduced Lignin content, and the syringyl/Guaiacyl Lignin monomer ratio accompanied by the reduced expression of Lignin biosynthetic genes compared to nontransgenic plants. A moderate increase in the level of glucose release in these transgenic lines might be attributed to reduced biomass recalcitrance as a result of reduced Lignin content and Lignin composition. Our results suggest that overexpression of GA2ox genes in switchgrass is a feasible strategy to improve plant architecture and reduce biomass recalcitrance for biofuel.
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two year field analysis of reduced recalcitrance transgenic switchgrass
Plant Biotechnology Journal, 2014Co-Authors: Mitra Mazarei, Holly L Baxter, David G J Mann, Nicole Labbe, Lindsey M Kline, Qunkang Cheng, Mark T WindhamAbstract:Summary Switchgrass (Panicum virgatum L.) is a leading candidate for a dedicated lignocellulosic biofuel feedstock owing to its high biomass production, wide adaptation and low agronomic input requirements. Lignin in cell walls of switchgrass, and other lignocellulosic feedstocks, severely limits the accessibility of cell wall carbohydrates to enzymatic breakdown into fermentable sugars and subsequently biofuels. Low-Lignin transgenic switchgrass plants produced by the down-regulation of caffeic acid O-methyltransferase (COMT), a Lignin biosynthetic enzyme, were analysed in the field for two growing seasons. COMT transcript abundance, Lignin content and the syringyl/Guaiacyl Lignin monomer ratio were consistently lower in the COMT-down-regulated plants throughout the duration of the field trial. In general, analyses with fully established plants harvested during the second growing season produced results that were similar to those observed in previous greenhouse studies with these plants. Sugar release was improved by up to 34% and ethanol yield by up to 28% in the transgenic lines relative to controls. Additionally, these results were obtained using senesced plant material harvested at the end of the growing season, compared with the young, green tissue that was used in the greenhouse experiments. Another important finding was that transgenic plants were not more susceptible to rust (Puccinia emaculata). The results of this study suggest that Lignin down-regulation in switchgrass can confer real-world improvements in biofuel yield without negative consequences to biomass yield or disease susceptibility.
Vincent L Chiang - One of the best experts on this subject based on the ideXlab platform.
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Phosphorylation is an on/off switch for 5-hydroxyconiferaldehyde O-methyltransferase activity in poplar monolignol biosynthesis
Proceedings of the National Academy of Sciences, 2015Co-Authors: Jack P Wang, Ying Chung Lin, David C Muddiman, Ling Chuang, Philip L. Loziuk, Hao Chen, Rui Shi, Ronald R. Sederoff, Vincent L ChiangAbstract:Although phosphorylation has long been known to be an important regulatory modification of proteins, no unequivocal evidence has been presented to show functional control by phosphorylation for the plant monolignol biosynthetic pathway. Here, we present the discovery of phosphorylation-mediated on/off regulation of enzyme activity for 5-hydroxyconiferaldehyde O-methyltransferase 2 (PtrAldOMT2), an enzyme central to monolignol biosynthesis for lignification in stem-differentiating xylem (SDX) of Populus trichocarpa. Phosphorylation turned off the PtrAldOMT2 activity, as demonstrated in vitro by using purified phosphorylated and unphosphorylated recombinant PtrAldOMT2. Protein extracts of P. trichocarpa SDX, which contains endogenous kinases, also phosphorylated recombinant PtrAldOMT2 and turned off the recombinant protein activity. Similarly, ATP/Mn2+-activated phosphorylation of SDX protein extracts reduced the endogenous SDX PtrAldOMT2 activity by ∼60%, and dephosphorylation fully restored the activity. Global shotgun proteomic analysis of phosphopeptide-enriched P. trichocarpa SDX protein fractions identified PtrAldOMT2 monophosphorylation at Ser123 or Ser125 in vivo. Phosphorylation-site mutagenesis verified the PtrAldOMT2 phosphorylation at Ser123 or Ser125 and confirmed the functional importance of these phosphorylation sites for O-methyltransferase activity. The PtrAldOMT2 Ser123 phosphorylation site is conserved across 93% of AldOMTs from 46 diverse plant species, and 98% of the AldOMTs have either Ser123 or Ser125. PtrAldOMT2 is a homodimeric cytosolic enzyme expressed more abundantly in syringyl Lignin-rich fiber cells than in Guaiacyl Lignin-rich vessel cells. The reversible phosphorylation of PtrAldOMT2 is likely to have an important role in regulating syringyl monolignol biosynthesis of P. trichocarpa.
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chemical and spatial differentiation of syringyl and Guaiacyl Lignins in poplar wood via time of flight secondary ion mass spectrometry
Analytical Chemistry, 2011Co-Authors: Chuanzhen Zhou, Quanzi Li, Vincent L Chiang, Lucian A Lucia, Dieter P. GriffisAbstract:As a major component in plant cell walls, Lignin is an important factor in numerous industrial processes, especially in wood saccharification and fermentation to biofuels. The ability to chemically differentiate and spatially locate Lignins in wood cell structures provides an important contribution to the effort to improve these processes. The spatial distribution of the syringyl (S) and Guaiacyl (G) Lignins, both over larger regions and within a single cell wall, on poplar (Populus trichocarpa) wood cross-sections was determined via time-of-flight secondary ion mass spectrometry (ToF-SIMS). This is the first time that direct chemically specific mass spectrometric mapping has been employed to elucidate the spatial distribution of S and G Lignins. In agreement with results obtained by UV microscopy, ToF-SIMS images clearly show that the Guaiacyl Lignin is predominantly located in the vessel cell walls of poplar wood while syringyl Lignin is mainly located in the fiber cell walls. The G/S ratio in vessel ce...
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genetic augmentation of syringyl Lignin in low Lignin aspen trees final report
2004Co-Authors: Chungjui Tsai, Mark F. Davis, Vincent L ChiangAbstract: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 asmore » 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.« less
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the last step of syringyl monolignol biosynthesis in angiosperms is regulated by a novel gene encoding sinapyl alcohol dehydrogenase
The Plant Cell, 2001Co-Authors: Laigeng Li, Xiao Fei Cheng, Jacqueline Leshkevich, Scott A. Harding, Toshiaki Umezawa, Vincent L ChiangAbstract:Cinnamyl alcohol dehydrogenase (CAD; EC 1.1.1.195) has been thought to mediate the reduction of both coniferaldehyde and sinapaldehyde into Guaiacyl and syringyl monolignols in angiosperms. Here, we report the isolation of a novel aspen gene ( PtSAD ) encoding sinapyl alcohol dehydrogenase (SAD), which is phylogenetically distinct from aspen CAD (PtCAD). Liquid chromatography‐mass spectrometry-based enzyme functional analysis and substrate level‐controlled enzyme kinetics consistently demonstrated that PtSAD is sinapaldehyde specific and that PtCAD is coniferaldehyde specific. The enzymatic efficiency of PtSAD for sinapaldehyde was � 60 times greater than that of PtCAD. These data suggest that in addition to CAD, discrete SAD function is essential to the biosynthesis of syringyl monolignol in angiosperms. In aspen stem primary tissues, PtCAD was immunolocalized exclusively to xylem elements in which only Guaiacyl Lignin was deposited, whereas PtSAD was abundant in syringyl Lignin‐enriched phloem fiber cells. In the developing secondary stem xylem, PtCAD was most conspicuous in Guaiacyl Lignin‐enriched vessels, but PtSAD was nearly absent from these elements and was conspicuous in fiber cells. In the context of additional protein immunolocalization and Lignin histochemistry, these results suggest that the distinct CAD and SAD functions are linked spatiotemporally to the differential biosynthesis of Guaiacyl and syringyl Lignins in different cell types. SAD is required for the biosynthesis of syringyl Lignin in angiosperms.
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secondary xylem specific expression of caffeoyl coenzyme a 3 o methyltransferase plays an important role in the methylation pathway associated with Lignin biosynthesis in loblolly pine
Plant Molecular Biology, 1999Co-Authors: Yuriko Osakabe, Chandrashekhar P Joshi, Vincent L ChiangAbstract:Two types of structurally distinct O-methyltransferases mediate the methylation of hydroxylated monomeric Lignin precursors in angiosperms. Caffeate 3-O-methyltransferase (COMT; EC 2.1.1.68) methylates the free acids and caffeoyl CoA 3-O-methyltransferase (CCoAOMT; EC 2.1.1.104) methylates coenzyme A esters. Recently, we reported a novel hydroxycinnamic acid/hydroxycinnamoyl CoA ester O-methyltransferase (AEOMT) from loblolly pine differentiating xylem that was capable of methylating both acid and ester precursors with similar efficiency. In order to determine the possible existence and role of CCoAOMT in Lignin biosynthesis in gymnosperms, a 1.3 kb CCoAOMT cDNA was isolated from loblolly pine that showed 79–82% amino acid sequence identity with many angiosperm CCoAOMTs. The recombinant CCoAOMT expressed in Escherichia coli exhibited a significant methylating activity with hydroxycinnamoyl CoA esters whereas activity with hydroxycinnamic acids was insignificant. Moreover, 3.2 times higher catalytic efficiency for methylating caffeoyl CoA over 5-hydroxyferuloyl CoA was observed which could serve as a driving force towards synthesis of Guaiacyl Lignin. The secondary xylem-specific expression of CCoAOMT was demonstrated using RNA blot analysis, western blot analysis, and O-methyltransferase enzyme assays. In addition, Southern blot analysis indicated that CCoAOMT may exist as a single-copy gene in loblolly pine genome. The transgenic tobacco plants carrying loblolly pine CCoAOMT promoter-GUS fusion localized the site of GUS activity at the secondary xylem tissues. These data suggest that CCoAOMT, in addition to AEOMT, plays an important role in the methylation pathway associated with Lignin biosynthesis in loblolly pine.
Timothy R Filley - One of the best experts on this subject based on the ideXlab platform.
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the application of 13c labeled tetramethylammonium hydroxide 13c tmah thermochemolysis to the study of fungal degradation of wood
Organic Geochemistry, 2000Co-Authors: Timothy R Filley, Patrick G Hatcher, W C Shortle, R T PraseuthAbstract:This paper presents the results from an assessment of the application of a new molecular analytical procedure, 13 CTMAH thermochemolysis, to study the chemical modification of Lignin by white-rot and brown-rot fungi. This technique diAers from other molecular chemolysis procedures (e.g. TMAH thermochemolysis and CuO alkaline oxidation) as it enables one to determine the amount of hydroxylated aromatic components in degraded Lignin residues through a selective Lignin depolymerization and 13 C-labeled methylation reaction. Major diAerences were observed in the chemical composition and yield of Lignin monomers released from a limited sample set of field and laboratory inoculation brown-rot and white-rot degraded residues when analyzed by 13 C-TMAH thermochemolysis. The brown-rot residues were characterized by high yields of 3,4-dihydroxy phenyl compounds, presumably due to fungal demethylation of methoxyl groups on Guaiacyl Lignin, and relatively low yields of aromatic acids that result from microbial side chain oxidation. The white-rot residues were characterized by low yields of demethylated Lignin monomers but relatively high yields of monomers exhibiting side chain oxidation. If generally applicable, this distinct chemical functionality has important implications for the chemical reactivity and solubility of degraded wood residues and consequently the cycling of terrestrial carbon in the geosphere. The 13 C-TMAH thermochemolysis procedure provides a rapid and sensitive tool for tracking microbial modifications of Lignin in terrestrial environments including coastal sediments, forest soils and waters receiving terrestrial organic matter. # 2000 Elsevier Science Ltd. All rights reserved.
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tetramethylammonium hydroxide tmah thermochemolysis proposed mechanisms based upon the application of 13c labeled tmah to a synthetic model Lignin dimer
Organic Geochemistry, 1999Co-Authors: R D Minard, Timothy R Filley, Patrick G HatcherAbstract:Abstract The mechanism by which heated tetramethylammonium hydroxide (TMAH) degrades the Lignin biopolymer was investigated by the novel application of 13C-labeled TMAH (13C-TMAH) in the thermochemolysis of a synthetic model Guaiacyl Lignin dimer. GC-MS analysis of the products showed labeling patterns consistent with a base-catalyzed intramolecular displacement of the β-phenoxy group and the formation of two intermediate Guaiacyl propane epoxides, a γ-hydroxy-α,β-epoxide and an α-hydroxy-β,γ-epoxide. Methoxide then functions as a nucleophile to open the epoxide ring. These results substantiate the base-catalyzed reactions previously postulated by Gierer (1970) to explain alkali wood pulping and also explain the facile formation and distribution of Lignin derivatives obtained in the TMAH thermochemolysis of natural samples. The absence of substantial numbers of bonds involving propyl-aryl ether linkages with adjacent hydroxyl groups is the limiting factor in the complete decomposition of Lignin by TMAH thermochemolysis, as propyl-aryl ether linkages without adjacent hydroxyl groups cannot react via this mechanism. This helps to explain why materials such as highly degraded Lignin residues, with significant side chain alteration and type III kerogens above the rank of lignite, where aliphatic-aryl ether linkages are thought to be insignificant, are reported to give low yields of TMAH thermochemolysis products.
