Common Ivy (Hedera Helix L.) as a Novel Green Resource in an Urban Biorefinery Concept

Common ivy (CI) or Hedera Helix L., is a clinging evergreen vine that can be cultivated on any vertical surface (walls, fences, tree trunks, etc.). In Europe, CI has been recommended by governments to plant in urban areas because it lowers urban heat island effects and improves urban air quality. Regular trimmings of these vertical greenery systems would be necessary, which would yield a potentially interesting novel biomass resource for urban biorefinery concepts. Furthermore, CI extracts contain pharmaceutically active compounds (e.g., hederacoside C and a-hederin), which constitute the active components of commercially available cough syrups. Moreover, research on their suitability to treat (lung) inflammations and suppress cancer tumor growth is ongoing and shows promise. CI extracts also have demonstrated potential for their application in the agricultural industry to serve as antifungal agents. Recently, postextracted residues of CI have shown to be a promising feedstock for green fertilizer production via slow pyrolysis. Moreover, a provisional sustainability assessment indicated that the proposed process would be both carbon- and energy-negative. Therefore, a novel circular biorefinery approach is proposed, which entails the lifecycle of CI, from cultivation in vertical ecosystems via refinery into bioproduct(s) and valuable nutrients, and then back into soil.