Eutectic mixtures of natural origin as new stimulant formulations for pine resin production

abstract

Pine trees exudate resin as a defense mechanism against external threats. To increase resin production for industrial applications, stimulant formulations commonly based on sulfuric acid are often used. However, sulfuric acid-based paste poses numerous risks, making the development of more sustainable and safer alternatives necessary. The present study explores stimulant formulations of natural origin based on eutectic mixtures (ES), containing both bio-based acidic hydrogen bond donors (HBD) and hydrogen bond acceptors (HBA) that can act as resin production stimulants. The results show that these formulations, especially F10 (choline chloride:oxalic acid (molar ratio 1:1) + ferrous sulfate), F14 (choline chloride:oxalic acid (molar ratio 1:1) + 20% ethylene glycol (w/w)) + ferrous sulfate) and F15 (choline chloride:oxalic acid (molar ratio 2:1) + ferrous sulfate), promote production resin yields 2.6-, 2.4-, and 3.0-folds higher than those obtained with a sulfuric acid-based paste. Increased resin production yields with ES-based formulations could result from the synergic effect of the acidity of the HBD, with the ability of HBA to enhance plant development, and the stimulant action of ferrous and potassium ions as cofactors of terpene synthases. Gas Chromatography-Mass Spectrometry (GC-MS) analyses demonstrated that the obtained resins have similar turpentine and rosin chemical composition to those obtained with sulfuric acid-based paste, which is suitable for industrial applications. Therefore, the new ES-based formulations developed are promising, safer, and more sustainable alternatives to produce pine resin.

authors

Inês S.L. Farias, Nalin Seixas, Carla Vilela, Sónia A.O. Santos, Carmen S.R. Freire, Joana Vieira, Marco Ribeiro, Maria Emília Silva, Armando J.D. Silvestre

Groups

G4 - Renewable Materials and Circular Economy

Projects

Inovação na Fileira da Resina Natural para Reforço da Bioeconomia Nacional (RN21)

Collaboratory for Emerging Technologies, CoLab (EMERGING TECHNOLOGIES)

Nano-argilas para remoção/captura de fosfatos (P) e sua reutilização como fertilizante (NATURAL)

CICECO-Aveiro Institute of Materials R&D Unit Pluriannual Funding (CICECO-Aveiro Institute of Materials)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

PRR CICECO - Instituto de Materiais de Aveiro (Equipar+ CICECO)

acknowledgements

This research was developed within the scope of the Integrated Project RN21 - Inovação na Fileira da Resina Natural para Reforço da Bioeconomia Nacional, is co-financed by the Environmental Fund through Component 12 – Promotion of the Sustainable Bioeconomy (Investment TC-C12-i01 – Sustainable Bioeconomy No. 02-C12-i01.01-2022.P6), of the European funds allocated to Portugal by the Recovery and Resilience Plan (PRR), within the scope of the Recovery and Resilience Mechanism (MRR) of the European Union (EU), framed in the Next Generation EU, for the period 2021–2026. The project CICECO-Aveiro Institute of Materials, UID/50011/2025 (DOI 10.54499/UID/50011/2025) & LA/P/0006/2020 (DOI 10.54499/LA/P/0006/2020) & UID/PRR/50011/2025 (DOI 10.54499/UID/PRR/50011/2025), and of the project UID/04033/2023: Centre for the Research and Technology of Agro-Environmental and Biological Sciences and LA/P/0126/2020 (DOI 10.54499/LA/P/0126/2020) both financed by national funds through the FCT/MCTES (PIDDAC) are also acknowledged. Acknowledgements are also due to FCT/MCTES for the research contract under Scientific Employment Stimulus to S.A.O. Santos (2021.03348. CEECIND).