TY - JOUR
T1 - Evaluation of chemical additives in hydrothermal pre-treatment of wood for the integrated production of monosugars and hydrolysis lignins for PLA-based biocomposites
AU - Borrega, Marc
AU - Pihlajaniemi, Ville
AU - Liitiä, Tiina
AU - Wikström, Lisa
AU - Tamminen, Tarja
N1 - Funding Information:
Business Finland is acknowledged for funding the project “Lignin First Concept for High Value Applications” via the BioNets program. Juha Haakana, Atte Mikkelson, Riitta Alander, Mariitta Svanberg, Jarna Teikari, Tommi Virtanen, Pia Willberg-Keyriläinen, Markus Nikinmaa, Sini-Tuuli Rauta, Enni Luoma, and Juha Mannila are thanked for their skillful support with the hydrothermal pre-treatments, enzymatic hydrolysis trials, chemical and structural analyses, and composite preparation.
Publisher Copyright:
© 2021, The Author(s).
PY - 2023/6
Y1 - 2023/6
N2 - The use of chemical additives (1- and 2-naphthol, formaldehyde) in hydrothermal pre-treatments of pine, birch, and willow wood was evaluated to minimize lignin condensation reactions and consequently improve the saccharification of the pre-treated materials. The residual hydrolysis lignins were then tested in the preparation of polylactic acid (PLA)-based composites. The results showed that addition of 2-naphthol to the hydrothermal pre-treatment increased the saccharification of pine wood by twofold compared to water-only experiments, but the sugar yield was only 50% of the carbohydrate content in the pre-treated pine. The use of 2-naphthol and formaldehyde also improved somewhat the saccharification of bark-containing willow wood, while the use of 1-naphthol had no effect on the saccharification of any of the pre-treated materials. In birch and willow (without bark), almost complete saccharification could be achieved even without additives. Analyses of hydrolysis lignins from birch revealed structural changes caused by the additives, which were consistent with a reduction of condensation reactions. Selected lignins were successfully used at 20% loading in PLA/lignin composites; however, variation in mechanical properties among composites prepared with different lignins was only minor. In general, the use of lignin decreased the strength and ductility of PLA but increased the stiffness. Based on these results, the use of additives may only be beneficial in the pre-treatment of pine or other softwoods to improve the sugar yields.
AB - The use of chemical additives (1- and 2-naphthol, formaldehyde) in hydrothermal pre-treatments of pine, birch, and willow wood was evaluated to minimize lignin condensation reactions and consequently improve the saccharification of the pre-treated materials. The residual hydrolysis lignins were then tested in the preparation of polylactic acid (PLA)-based composites. The results showed that addition of 2-naphthol to the hydrothermal pre-treatment increased the saccharification of pine wood by twofold compared to water-only experiments, but the sugar yield was only 50% of the carbohydrate content in the pre-treated pine. The use of 2-naphthol and formaldehyde also improved somewhat the saccharification of bark-containing willow wood, while the use of 1-naphthol had no effect on the saccharification of any of the pre-treated materials. In birch and willow (without bark), almost complete saccharification could be achieved even without additives. Analyses of hydrolysis lignins from birch revealed structural changes caused by the additives, which were consistent with a reduction of condensation reactions. Selected lignins were successfully used at 20% loading in PLA/lignin composites; however, variation in mechanical properties among composites prepared with different lignins was only minor. In general, the use of lignin decreased the strength and ductility of PLA but increased the stiffness. Based on these results, the use of additives may only be beneficial in the pre-treatment of pine or other softwoods to improve the sugar yields.
KW - Additives
KW - Composites
KW - Hydrothermal pre-treatment
KW - Lignin
KW - PLA
KW - Saccharification
UR - http://www.scopus.com/inward/record.url?scp=85101280060&partnerID=8YFLogxK
U2 - 10.1007/s13399-021-01365-5
DO - 10.1007/s13399-021-01365-5
M3 - Article
AN - SCOPUS:85101280060
SN - 2190-6815
VL - 13
SP - 7491
EP - 7503
JO - Biomass Conversion and Biorefinery
JF - Biomass Conversion and Biorefinery
IS - 9
ER -