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Design paths for structural polyesters, dependent on feedstock, (biobased) monomers, resulting polymers, and production technologies. In principle, a comprehensive safe and sustainable by design (SSbD) approach would require the individual comparison of all different pathways in a life cycle assessment, further multiplied by the numerous applications of the polymers in systems and products. This is not feasible, and SSbD for polymers must therefore be conducted in a modular fashion.
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To achieve a sustainable circular economy, polymers need to start transitioning to recycled and biobased feedstock and accomplish CO2 emission neutrality. This is not only true for structural polymers, such as in packaging or engineering applications, but also for functional polymers in liquid formulations, such as adhesives, lubricants, thickeners...
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Context 1
... This consideration of the level of dependence between two polyesters in the categories of molecular design, properties, and production technologies resembles the application of the "phylogenetic tree" principle in biology. [57] The key property of industrial compostability of different polyesters can be achieved by vastly different synthesis approaches ranging from polycondensation (PBS, PBAT) and ringopening polymerization (PLA) to direct fermentation (PHA) (Figure 8). ...
Citations
... Without biorenewable circularity, we will continue to consume the dwindling supply of fossil resources to meet the rapidly growing demand for plastics 8 ; moreover, we will have few incentives to recover plastic waste for recycling and reuse, failing to meet our goals for sustainable manufacturing. Future generations of plastics should emphasize bio-advantaged designs that achieve high efficiency in chemical recycling with respect to monomer recovery at end of life 6,9 , so that the biorenewable content may be recirculated across the maximum possible number of manufacturing cycles. If this was realized, there could be a confluence of performance, manufacturing and economic benefits to motivate the switch to new materials in the transition to a circular bio-plastics economy. ...
Amid growing concerns over the human health and environmental impacts of plastic waste, the most promising solution would be to build a circular plastics economy where sustainability considerations dictate the full life cycle of plastics use including replacing petrochemicals with biorenewables. Here we show that by incorporating the polyketide triacetic acid lactone (TAL) in polydiketoenamines (PDK) we increase the working temperature of these circular plastics, opening the door wider to applications where circularity is urgently needed. By varying the number of carbons of TAL-derived monomers, both polymer properties and recycling efficiency are affected. Simply using glucose as the main carbon source, we engineered a process for producing bioTAL under fed-batch fermentation. A systems analysis of this bioprocess under different scenarios quantifies the environmental and economic benefits of PDK plastics and the risks when implemented at an industrial scale, providing opportunities in biorenewable circularity.
Dye-decolorizing Peroxidases (DyPs) are heme-containing enzymes in fungi and bacteria that catalyze the reduction of hydrogen peroxide to water with concomitant oxidation of various substrates, including anthraquinone dyes, lignin-related phenolic and non-phenolic compounds, and metal ions. Investigation of DyPs has shed new light on peroxidases, one of the most extensively studied families of oxidoreductases; still, details of their microbial physiological role and catalytic mechanisms remain to be fully disclosed. They display a distinctive ferredoxin-like fold encompassing anti-parallel β-sheets and α-helices, and long conserved loops surround the heme pocket with a role in catalysis and stability. A tunnel routes H2O2 to the heme pocket, whereas binding sites for the reducing substrates are in cavities near the heme or close to distal aromatic residues at the surface. Variations in reactions, the role of catalytic residues, and mechanisms were observed among different classes of DyP. They were hypothetically related to the presence or absence of distal H2O molecules in the heme pocket. The engineering of DyPs for improved properties directed their biotechnological applications, primarily centered on treating textile effluents and degradation of other hazardous pollutants, to fields such as biosensors and valorization of lignin, the most abundant renewable aromatic polymer. In this review, we track recent research contributions that furthered our understanding of the activity, stability, and structural properties of DyPs and their biotechnological applications. Overall, the study of DyP-type peroxidases has significant implications for environmental sustainability and the development of new bio-based products and materials with improved end-of-life options via biodegradation and chemical recyclability, fostering the transition to a sustainable bio-based industry in the circular economy realm.
