Journal Article

A new approach to zip-lignin

Mahon, Elizabeth L., Loqué, Dominique, Kim, Kwang Ho, Unda, Faride, Mottiar, Yaseen, Eudes, Aymerick, Karlen, Steven D., Ralph, John, Mansfield, Shawn D.

2022

Overview

• Renewed interests in the development of bioenergy, biochemicals, and biomaterials have elicited new strategies for engineering the lignin of biomass feedstock plants. This study shows, for the first time, that 3,4-dihydroxybenzoate (DHB) is compatible with the radical coupling reactions that assemble polymeric lignin in plants. • We introduced a bacterial 3-dehydroshikimate dehydratase into hybrid poplar (Populus alba × grandidentata) to divert carbon flux away from the shikimate pathway, which lies upstream of lignin biosynthesis. • Transgenic poplar wood had up to 33% less lignin with p-hydroxyphenyl units comprising as much as 10% of the lignin. Mild alkaline hydrolysis of transgenic wood released fewer ester-linked p-hydroxybenzoate groups than control trees, and revealed the novel incorporation of cell-wall-bound DHB, as well as glycosides of 3,4-dihydroxybenzoic acid (DHBA). Two-dimensional nuclear magnetic resonance (2D-NMR) analysis uncovered DHBA-derived benzodioxane structures suggesting that DHB moieties were integrated into the lignin polymer backbone. In addition, up to 40% more glucose was released from transgenic wood following ionic liquid pretreatment and enzymatic hydrolysis. • This work highlights the potential of diverting carbon flux from the shikimate pathway for lignin engineering and describes a new type of ‘zip-lignin’ derived from the incorporation of DHB into poplar lignin.

• Publisher: Wiley,Wiley Subscription Services, Inc,John Wiley and Sons Inc
• Subject: 4-hydroxybenzoic acid / acylated monolignols / Addition polymerization / alkaline hydrolysis / BASIC BIOLOGICAL SCIENCES / biocompatible materials / bioenergy / Biomass / biomass feedstock engineering / Biomaterials / Biomedical materials / Biosynthesis / Carbon / Chemical reactions / Dehydration / Dihydroxybenzoic acid / Engineering / enzymatic hydrolysis / Enzymolysis / feedstocks / genetically modified organisms / glucose / Glycosides / Hardwoods / hybrids / Hydrolysis / Ionic liquids / lignification / Lignin / lignin valorization / NMR / Nuclear magnetic resonance / nuclear magnetic resonance spectroscopy / Polymers / Poplar / poplar trees / Populus alba / Populus alba x grandidentata / Populus alba × grandidentata / shikimate pathway / Two dimensional analysis / Wood / zip-lignin