Formaldehyde stabilization facilitates lignin monomer production during biomass depolymerization

• Published in: Science (American Association for the Advancement of Science) Vol. 354; no. 6310; pp. 329 - 333
• Main Authors: Shuai, Li, Amiri, Masoud Talebi, Questell-Santiago, Ydna M., Héroguel, Florent, Li, Yanding, Kim, Hoon, Meilan, Richard, Chapple, Clint, Ralph, John, Luterbacher, Jeremy S.
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 21.10.2016; The American Association for the Advancement of Science; American Association for the Advancement of Science (AAAS)
• Subjects: Aldehydes; Biodiesel fuels; Biomass; Biorefineries; Carbon; Carbon-carbon composites; Catalysis; Cellulose; Cellulose - chemistry; Chemical Fractionation; Depolymerization; Formaldehyde; Formaldehyde - chemistry; Fractions; Lignin; Lignin - biosynthesis; Lignin - chemistry; Linkages; Moles; Monomers; Plant biomass; Plants, Genetically Modified - chemistry; Plants, Genetically Modified - genetics; Polymerization; Polymers; Polysaccharides - chemistry; Populus - chemistry; Populus - genetics; Pretreatment; Raw materials
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.aaf7810

Practical, high-yield lignin depolymerization methods could greatly increase biorefinery productivity and profitability. However, development of these methods is limited by the presence of interunit carbon-carbon bonds within native lignin, and further by formation of such linkages during lignin extraction. We report that adding formaldehyde during biomass pretreatment produces a soluble lignin fraction that can be converted to guaiacyl and syringyl monomers at near theoretical yields during subsequent hydrogenolysis (47 mole % of Klason lignin for beech and 78 mole % for a high-syringyl transgenic poplar). These yields were three to seven times those obtained without formaldehyde, which prevented lignin condensation by forming 1,3-dioxane structures with lignin side-chain hydroxyl groups. By depolymerizing cellulose, hemicelluloses, and lignin separately, monomer yields were between 76 and 90 mole % for these three major biomass fractions.