Abstract :
[en] As the deleterious effects of synthetic pesticides on human health and the environment are now well recognized, the demand for natural alternatives continues to increase. In this context, the identification of new bio-based resources for the development of more sustainable plant protection solutions represents a major challenge. In response to this sanitary and environmental urgency, the EXTRABARK project proposes an innovative approach based on the valorization of bark through the extraction of active molecules with biocidal activities, for the replacement of chemical products used in agriculture and the wood industry. Bark is indeed a main by-product of the forestry industry that represents each year millions of tons of largely underexploited biomass. This abundant and renewable resource, rich in bioactive compounds with valuable properties, is mainly used as fuel or mulch.
The EXTRABARK project therefore aims to extract, characterize, and valorize biocidal secondary metabolites from regional forest bark to develop more environmentally friendly bio-based solutions. To achieve this, ten target tree species were selected based on their availability and potential for future deployment in the Greater Region and subsequently subjected to four complementary green extraction processes (hydrodistillation, supercritical CO2 extraction, and aqueous and hydroethanolic maceration), followed by characterization using chromatographic techniques coupled to mass spectrometry (GC-MS and LC-MS/MS).
In total, four extracts were produced per species, resulting in forty extracts evaluated in biocidal assays, including herbicidal tests against the weeds Lolium perenne and Trifolium pratense, and fungicidal tests against phytopathogenic fungi affecting crops, namely Aspergillus flavus and Fusarium verticillioides. Chemical characterization of the extracts revealed the presence of various families of secondary metabolites, particularly terpenes (α-pinene, caryophyllene, etc.) and phenolic compounds (taxifolin, gallocatechin, etc.), enabling links to be established between chemical composition and the observed biological activities. Several aqueous and hydroethanolic extracts exhibited promising herbicidal and fungicidal activities, varying according to tree species and extraction process.
These results highlight the potential of bark as a source of bio-based molecules with biocidal activity, while the project’s integrated approach, supported by the diversity of the partners involved, enables bark valorization strategies that reconcile industrial constraints with agricultural needs.
