Lignin is the major limiting factor in the convers ion of lignocellulosic biomass into liquid biofuels. Over the past decade, resear chers have made a number of exciting observations that have significantly exten ded our possibilities of... more
Lignin is the major limiting factor in the convers ion of lignocellulosic biomass into liquid biofuels. Over the past decade, resear chers have made a number of exciting observations that have significantly exten ded our possibilities of engineering plant cell walls. One of these findings is that pl ants can tolerate large variations in the composition of the normal lignin
Research Interests: Biomass, Energy, Biology, Metabolomics, Biofuels, and 4 morePlant growth, Wood Quality, Plant Cell Wall, and Cell Wall
Lignin is a complex phenolic polymer deposited in secondarily-thickened plant cell walls. The polymer is mainly derived from the three primary monolignols: p-coumaryl, coniferyl and sinapyl alcohol which give rise to p-hydroxyphenyl,... more
Lignin is a complex phenolic polymer deposited in secondarily-thickened plant cell walls. The polymer is mainly derived from the three primary monolignols: p-coumaryl, coniferyl and sinapyl alcohol which give rise to p-hydroxyphenyl, guaiacyl and syringyl units (H, G and S units, respectively) when coupled into the polymer. The building blocks differ in their degree of methoxylation and their biosynthetic pathway is catalyzed by more than 10 enzymes. HCT plays a crucial role by channeling the phenylpropanoids towards the production of coniferyl and sinapyl alcohols. Interestingly, HCT has been reported to be implicated in the pathway both upstream and downstream of the 3-hydroxylation of the aromatic ring of p-coumaroyl shikimate (Figure 1) (Hoffmann et al., 2003; Hoffmann et al., 2004; Vanholme et al., 2013b). These features highlight the importance of developing an assay to reliably measure HCT activity in planta. Here, we describe a UPLC-MS-based method for the analysis of HCT ac...
Bacteria-derived enzymes that can modify specific lignin substructures are potential targets to engineer plants for better biomass processability. The Gram-negative bacterium Sphingobium sp. SYK-6 possesses a Cα-dehydrogenase (LigD)... more
Bacteria-derived enzymes that can modify specific lignin substructures are potential targets to engineer plants for better biomass processability. The Gram-negative bacterium Sphingobium sp. SYK-6 possesses a Cα-dehydrogenase (LigD) enzyme that has been shown to oxidize the α-hydroxy functionalities in β-O-4-linked dimers into α-keto analogues that are more chemically labile. Here, we show that recombinant LigD can oxidize an even wider range of β-O-4-linked dimers and oligomers, including the genuine dilignols, guaiacylglycerol-β-coniferyl alcohol ether and syringylglycerol-β-sinapyl alcohol ether. We explored the possibility of using LigD for biosynthetically engineering lignin by expressing the codon-optimized ligD gene in Arabidopsis thaliana. The ligD cDNA, with or without a signal peptide for apoplast targeting, has been successfully expressed, and LigD activity could be detected in the extracts of the transgenic plants. UPLC-MS/MS-based metabolite profiling indicated that lev...
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Although the primary structure of proteins, nucleic acids, and carbohydrates can be readily determined, no sequencing method has been described yet for the second most abundant biopolymer on earth (i.e. lignin). Within secondary-thickened... more
Although the primary structure of proteins, nucleic acids, and carbohydrates can be readily determined, no sequencing method has been described yet for the second most abundant biopolymer on earth (i.e. lignin). Within secondary-thickened plant cell walls, lignin forms an aromatic mesh arising from the combinatorial radical-radical coupling of monolignols and many other less abundant monomers. This polymerization process leads to a plethora of units and linkage types that affect the physicochemical characteristics of the cell wall. Current methods to analyze the lignin structure focus only on the frequency of the major monomeric units and interunit linkage types but do not provide information on the presence of less abundant unknown units and linkage types, nor on how linkages affect the formation of neighboring linkages. Such information can only be obtained using a sequencing approach. Here, we describe, to our knowledge for the first time, a sequencing strategy for lignin oligome...
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Research Interests: Genetics, Renewable Energy, Metabolism, Systems Biology, Biomass, and 25 moreBioenergy, Plant Biology, Mass Spectrometry, Metabolomics, Functional Genomics, Transcriptome, Biofuels, Inflorescence, Mutation, Cluster Analysis, Fragmentation, Lignin, Arabidopsis, Phenotype, Genes, High Pressure Liquid Chromatography, Phenols, Gas Chromatography/mass Spectrometry, Phenotypes, Plant cell, Inflorescences, Mutants, Metabolome, Biosynthetic Pathways, and Biochemistry and cell biology(Bioenergy, Plant Biology, Mass Spectrometry, Metabolomics, Functional Genomics, Transcriptome, Biofuels, Inflorescence, Mutation, Cluster Analysis, Fragmentation, Lignin, Arabidopsis, Phenotype, Genes, High Pressure Liquid Chromatography, Phenols, Gas Chromatography/mass Spectrometry, Phenotypes, Plant cell, Inflorescences, Mutants, Metabolome, Biosynthetic Pathways, and Biochemistry and cell biology)
(Bioenergy, Plant Biology, Mass Spectrometry, Metabolomics, Functional Genomics, Transcriptome, Biofuels, Inflorescence, Mutation, Cluster Analysis, Fragmentation, Lignin, Arabidopsis, Phenotype, Genes, High Pressure Liquid Chromatography, Phenols, Gas Chromatography/mass Spectrometry, Phenotypes, Plant cell, Inflorescences, Mutants, Metabolome, Biosynthetic Pathways, and Biochemistry and cell biology)