Open AccessDegradation of lignin β‐aryl ether units in Arabidopsis thaliana expressing LigD , LigF and LigG from Sphingomonas paucimobilis SYK ‐6
Author(s) -
Mnich Ewelina,
Vanholme Ruben,
Oyarce Paula,
Liu Sarah,
Lu Fachuang,
Goeminne Geert,
Jørgensen Bodil,
Motawie Mohammed S.,
Boerjan Wout,
Ralph John,
Ulvskov Peter,
Møller Birger L.,
Bjarnholt Nanna,
Harholt Jesper
Publication year - 2017
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1111/pbi.12655
Subject(s) - sphingomonas paucimobilis , lignin , ether , biology , arabidopsis thaliana , cell wall , arabidopsis , biochemistry , ether cleavage , hydrolysis , aryl , sphingomonas , chemistry , organic chemistry , botany , mutant , gene , bacteria , 16s ribosomal rna , genetics , alkyl
Summary 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 ( Lig DFG ) 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 Lig DFG , showing the applicability of our approach. Additional new information on substrate specificity of the Lig DFG enzymes is also provided.