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Every twig and splinter used Plant-based production of commodity chemicals faces steep competition from fossil resources, which are often cheaper and easier to partition. Sustainable use of renewable resources requires strategies for converting complex and recalcitrant biomolecules into streams of chemicals with extraordinary efficiency. Liao et al. developed a biorefinery concept in which wood is eventually fully converted into useful chemicals: phenol, propylene, pulp amenable to ethanol production, and phenolic oligomers that can be incorporated into ink production (see the Perspective by Zhang). A life-cycle assessment and techno-economic analysis highlight the efficiency of the process and reveal the potential for such biorefinery strategies to contribute to sustainable chemicals markets. Science , this issue p. 1385 ; see also p. 1305

The environmental and economic challenges currently faced by the wax market may be addressed by the use of sustainable bio-based alternatives. Hereto, ketonization of vegetable oils and animal fats is a potential clean reaction route towards ketone bio-waxes. In the presence of a heterogeneous TiO2 catalyst, palm fatty acid distillate (PFAD) and other commercial feedstock are selectively coupled to bio-waxes in a solvent-less liquid phase ketonization process. The resulting ketone bio-waxes show similar, if not better water repellence properties than the current benchmark paraffin waxes when tested as hydrophobization agents in aqueous wax emulsions for wood composite materials. Despite the efficient utilization of biomass carbon in accord with the prescribed Green Chemistry principles in the catalytic ketonization reaction, sustainable end products are not always guaranteed. Depending on the substrate and system scenario, the comparative life cycle assessment (LCA) shows significantly lower or higher carbon footprints in comparison to fossil paraffin. Cultivation of biomass feedstock, catalyst production and the end-of-life phase are identified as the three major hotspots in the life cycle, while the gate-to-gate impact of the proposed ketonization process design itself is rather limited. Advice is formulated to considerably improve LCA of ketone bio-waxes, achieving sustainable waxy products with appreciably lower CO2 footprints than the fossil paraffin waxes.

International audience; Substitution of fossil energy sources for bio-based ones will require development of efficient processes that can convert inedible and preferably low-value fractions that currently are not used into high-value products. It is desirable that such processes are developed so that both current logistics and infrastructure can be used. Bark, which is the outer layer of woody biomass, is currently burnt in a low-value process or left in the forests to decay and is therefore considered waste. In this work, birch (Betula pendula) bark was converted to hydrocarbons suitable for use in both road and aviation fuels in two efficient steps. Development of an efficient, recyclable, salt- and metal-free solvent-based system to solubilize birch bark under benign reaction conditions was a key outcome. The obtained gum was composed of organosolv lignin and suberin oligomers and was fully characterized. This gum had unique properties and could be directly processed in a conventional hydroprocessing unit set-up to afford hydrocarbons in the road and aviation fuel ranges. Life cycle assessment was applied to evaluate different scenarios for implementing this technology. When using bark generated as a forestry by-product and current infrastructure in a pulp mill, the process had a favorable low carbon dioxide footprint for biofuel generation.

It is challenging to quantify the production of wood-based biomass, to define the type and where it comes from, how it is used, and the amount that remains available. This information is crucial for the implementation of national and transnational regulations and is a pillar for the development of the future bio-based circular economy. A variety of studies estimate the production of biomass, performs material flow analyses, or addresses supply chain modelling. These studies are often built upon distinct assumptions, tailored to a specific purpose, and often poorly described. This makes comparison amongst studies, generalization of results, or replication hard to even impossible. This paper presents a comprehensive methodology for wood-based biomass material flow analysis, anchored in Material Flow Analysis, built upon literature review and deducted through systematization of previous studies. This is a five-step approach, consisting of (1) adopt proper terminology, (2) obtain accurate estimates for the biomass flows, (3) Sankey diagram for resource balance representation, (4) scenario analysis, (5) stakeholders validation. The focus is to provide instructions for producing a generalized Sankey diagram, from the categorization of biomass resources, uses/applications in a circular economy setting, towards the development of scenario analysis. Its practical implementation is presented by defining the yearly wood-based biomass resource balance of Portugal and the waste wood resource balance of Flanders. The main data sources for the quantification of the biomass sources and uses/applications are identified. Based on the insights from these case studies, our methodological approach already shows to be replicable and with comparable results. This enables the comparison of resource flows between different regions and countries and also monitoring the progress over time. This leads to improved data which can be instruments for supporting companies&rsquo, decision-making processes (e.g., infrastructure investments or other strategic decisions), as well as designing policy strategies and incentives.