Tree bark characterization envisioning an integrated use in a biorefinery

Tree barks are considerable waste streams in forest industries, and a potentially interesting resource for biorefineries. Barks of six relevant tree species, namely poplar (Populus × canadensis), black locust (Robinia pseudoacacia), red oak (Quercus rubra), willow (Salix sp.), Corsican pine (Pinus nigra subsp. laricio), larch (Larix decidua), were anatomically chemically characterized. Anatomical analysis illustrated the structural heterogeneity different with occurrence various cell types their arrangement phloem, periderm, rhytidome. Summative chemical showed high extractive content (14–30 wt%) all barks. Black bark presented substantial suberin (10 wt%). The lignin was similar most (22–29 wt%), except (45 Analytical pyrolysis demonstrated that softwood mostly G type small amount H units, whereas hardwood species S, G, units present, low S/G ratios (0.3–0.7). wall polysaccharides rather low. Total monosaccharides ranged from 35 to 44 wt%, glucose being predominant almost barks, followed by xylose mannose Identification lipophilic extractives highlighted predominance resin acids fatty triterpenoids Analysis polar extracts revealed large variations phenolics (265–579 mg gallic acid equivalent/g extract), flavonoids (177–391 catechin condensed tannins (88–670 extract). Furthermore, antioxidant potential (500–1209 trolox as determined FRAP assay. Additionally, very strong activity (AAI > 2), evaluated DPPH assay, observed In summary, results highlight marked anatomical interspecies variability thus suggesting need tailored biorefining approaches.