title: Enzymatic Transesterification of Kraft Lignin with Long Acyl Chains in Ionic Liquids.
abstract: Valorization of lignin is essential for the economic viability of the biorefinery concept. For example, the enhancement of lignin hydrophobicity by chemical esterification is known to improve its miscibility in apolar polyolefin matrices, thereby helping the production of bio-based composites. To this end and due to its many reactive hydroxyl groups, lignin is a challenging macromolecular substrate for biocatalyzed esterification in non-conventional media. The present work describes for the first time the lipase-catalyzed transesterification of Kraft lignin in ionic liquids (ILs). Three lipases, three 1-butyl-3-methylimidazolium based ILs and ethyl oleate as long chain acyl donor were selected. Best results were obtained with a hydrophilic/hydrophobic binary IL system (1-butyl-3-methylimidazolium trifluoromethanesulfonate/1-butyl-3-methylimidazolium hexafluoro- phosphate, 1/1 v/v) and the immobilized lipase B from Candida antarctica (CALB) that afforded a promising transesterification yield (ca. 30%). Similar performances were achieved by using 1-butyl-3-methylimidazolium hexafluorophosphate as a coating agent for CALB rather than as a co-solvent in 1-butyl-3-methylimidazolium trifluoromethane-sulfonate thus limiting the use of hydrophobic IL. Structural characterization of lignin oleate was performed by spectroscopic studies (FTIR and ¹H-NMR). The synthesized lignin oleate exhibited interesting thermal and textural properties, different from those of the original Kraft lignin.
authors.affiliation: Unité de Génie Enzymatique et Cellulaire, FRE CNRS 3580, Université de Picardie Jules Verne, 33 Rue Saint-Leu, 80039 Amiens, France. lise.hulin@u-picardie.fr.
authors.forename: Lise
authors.initials: L
authors.lastname: Hulin
authors.affiliation: Unité de Génie Enzymatique et Cellulaire, FRE CNRS 3580, Université de Picardie Jules Verne, 33 Rue Saint-Leu, 80039 Amiens, France. eric.husson@u-picardie.fr.
authors.forename: Eric
authors.initials: E
authors.lastname: Husson
authors.affiliation: Laboratoire de Réactivité et Chimie des Solides, UMR CNRS 7314, Université de Picardie Jules Verne, 33 Rue Saint-Leu, 80039 Amiens, France. jean-pierre.bonnet@u-picardie.fr.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Bonnet
authors.affiliation: Sciences du Bois et de la Forêt, Centre de Recherche sur les Matériaux Renouvelables, Université Laval, 2425 Rue de la Terrasse, Québec, QC G1V 0A6, Canada. Tatjana.Stevanovic@sbf.ulaval.ca.
authors.forename: Tatjana
authors.initials: T
authors.lastname: Stevanovic
authors.affiliation: Unité de Génie Enzymatique et Cellulaire, FRE CNRS 3580, Université de Picardie Jules Verne, 33 Rue Saint-Leu, 80039 Amiens, France. catherine.sarazin@u-picardie.fr.
authors.forename: Catherine
authors.initials: C
authors.lastname: Sarazin
mesh_terms: D004951:Esterification; D052578:Ionic Liquids / Q000737:chemistry*; D008031:Lignin / Q000378:metabolism*; D008049:Lipase / Q000378:metabolism*
chemical_list: D052578:Ionic Liquids; C076151:Kraft lignin; D008031:Lignin; D008049:Lipase
keywords: enzymatic esterification; ionic liquids; lignin; lipase