Degradation of lignin β‐aryl ether units in Arabidopsis thaliana expressing LigD,LigF and LigG from Sphingomonas paucimobilis SYK‐6 |
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Authors: | Ewelina Mnich Ruben Vanholme Paula Oyarce Sarah Liu Fachuang Lu Geert Goeminne Bodil Jørgensen Mohammed S. Motawie Wout Boerjan John Ralph Peter Ulvskov Birger L. Møller Nanna Bjarnholt Jesper Harholt |
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Affiliation: | 1. Plant Biochemistry Laboratory, Department of Plant Biology and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark;2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium;3. Department of Plant Systems Biology, VIB, Ghent, Belgium;4. Department of Biochemistry and DOE Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, Madison, WI, USA;5. Section 6. for Plant Glycobiology, Department of Plant Biology and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark;7. Carlsberg Research Laboratory, Copenhagen, Denmark |
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Abstract: | Lignin is a major polymer in the secondary plant cell wall and composed of hydrophobic interlinked hydroxyphenylpropanoid units. The presence of lignin hampers conversion of plant biomass into biofuels; plants with modified lignin are therefore being investigated for increased digestibility. The bacterium Sphingomonas paucimobilis produces lignin‐degrading enzymes including LigD, LigF and LigG involved in cleaving the most abundant lignin interunit linkage, the β‐aryl ether bond. In this study, we expressed the LigD, LigF and LigG (LigDFG) genes in Arabidopsis thaliana to introduce postlignification modifications into the lignin structure. The three enzymes were targeted to the secretory pathway. Phenolic metabolite profiling and 2D HSQC NMR of the transgenic lines showed an increase in oxidized guaiacyl and syringyl units without concomitant increase in oxidized β‐aryl ether units, showing lignin bond cleavage. Saccharification yield increased significantly in transgenic lines expressing LigDFG, showing the applicability of our approach. Additional new information on substrate specificity of the LigDFG enzymes is also provided. |
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Keywords: | biofuel lignin modification bacteria
Sphingomonas paucimobilis
Ligβ ‐aryl ether saccharification yield |
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