Plant-derived waxes are attracting growing interest as renewable and sustainable alternatives to fossil-based materials, owing to their functional properties and broad applicability. Within this framework, the present study explored the valorisation potential of Spanish broom (Spartium junceum L.) stems through the recovery and chemical, thermal, and morphological characterization of waxes from their inner fibrous fraction. The effect of rehydration-assisted pre-treatment on wax extractability, chemical composition, supramolecular organization, and antimicrobial activity was systematically investigated. Broom stems were rehydrated for 2, 3, or 4 days prior to delamination and Soxhlet extraction with n-hexane. Wax recovery was strongly dependent on rehydration time, reaching a maximum after 3 days (≈2.3% w/w). LC–MS/MS analysis revealed a conserved wax composition across all samples, dominated by long-chain fatty alcohols and wax esters forming homologous series extending to very-high-molecular-weight species (≥C56), consistent with plant cuticular wax biosynthesis. Despite similar qualitative profiles, significant differences in thermal and morphological properties were observed. Differential scanning calorimetry showed increasing melting temperatures and fusion enthalpies from 2D to 3D and 4D samples. These trends were confirmed by scanning electron microscopy, which evidenced a transition from weakly structured morphologies to organized crystalline networks a more homogeneous and continuous microstructures with increasing rehydration time. Biological assays demonstrated selective antimicrobial activity against Gram-positive bacteria, particularly Streptococcus pyogenes, with waxes extracted after 3 and 4 days. The results highlight Spanish broom stems as a promising underexploited biomass for the production of functional natural waxes.
Natural waxes from Spartium junceum L. stem residues: Effect of rehydration time on yield, composition, and antimicrobial properties
La Torre C.;Buccafuri A.;Chidichimo G.;Caputo P.;Fazio A.;
2026-01-01
Abstract
Plant-derived waxes are attracting growing interest as renewable and sustainable alternatives to fossil-based materials, owing to their functional properties and broad applicability. Within this framework, the present study explored the valorisation potential of Spanish broom (Spartium junceum L.) stems through the recovery and chemical, thermal, and morphological characterization of waxes from their inner fibrous fraction. The effect of rehydration-assisted pre-treatment on wax extractability, chemical composition, supramolecular organization, and antimicrobial activity was systematically investigated. Broom stems were rehydrated for 2, 3, or 4 days prior to delamination and Soxhlet extraction with n-hexane. Wax recovery was strongly dependent on rehydration time, reaching a maximum after 3 days (≈2.3% w/w). LC–MS/MS analysis revealed a conserved wax composition across all samples, dominated by long-chain fatty alcohols and wax esters forming homologous series extending to very-high-molecular-weight species (≥C56), consistent with plant cuticular wax biosynthesis. Despite similar qualitative profiles, significant differences in thermal and morphological properties were observed. Differential scanning calorimetry showed increasing melting temperatures and fusion enthalpies from 2D to 3D and 4D samples. These trends were confirmed by scanning electron microscopy, which evidenced a transition from weakly structured morphologies to organized crystalline networks a more homogeneous and continuous microstructures with increasing rehydration time. Biological assays demonstrated selective antimicrobial activity against Gram-positive bacteria, particularly Streptococcus pyogenes, with waxes extracted after 3 and 4 days. The results highlight Spanish broom stems as a promising underexploited biomass for the production of functional natural waxes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
