Hydrogen bond competition driven cell wall deconstruction enables green extraction of Eucommia ulmoides gum using deep eutectic solvents

Eucommia ulmoides gum (EUG) is a natural trans−1,4-polyisoprene with promising applications in green elastomers and bio-based materials. However, its extraction is limited by strong confinement within a cellulose-hemicellulose-lignin matrix. This study aims to elucidate a hydrogen bond competition mechanism to enable efficient cell wall deconstruction and EUG release. Deep eutectic solvent systems were designed by tuning hydrogen bond donors and acceptors to selectively disrupt polysaccharide hydrogen bonding networks. The results show that hydrogen bond basicity, acidity, and viscosity collectively regulate solvent penetration and competitive interactions, with the choline chloride-lactic acid system providing the optimal balance between deconstruction efficiency and mass transfer. Spectroscopic analyses reveal pronounced weakening and rearrangement of cellulose and hemicellulose hydrogen bonding networks, which correlate with enhanced EUG release, structural loosening, and controlled molecular weight distribution. Coupling this system with petroleum ether extraction and optimizing conditions via response surface methodology achieves an EUG extraction yield of 20.76 ± 0.96%, with an extraction efficiency of 90.10 ± 4.17% and a purity of 98.24 ± 0.93%, while preserving EUG integrity. The extracted EUG retains its characteristic trans-1,4-polyisoprene structure and exhibits favorable thermal and mechanical properties. These findings provide a mechanism-driven basis for scalable and sustainable extraction processes and offer guidance for the rational design of solvent systems in industrial biomass valorization.