The development of new-generation plastics aims to mitigate environmental pollution by reducing reliance on petroleum-based raw materials. Among these, advanced polyester materials have gained attention due to their functional properties and sustainability potential. Thermoplastic segmented block copolyesters, composed of hard and soft segments, offer tunable properties for diverse applications [1]. However, their fossil-based origins pose environmental and social concerns. We explored a biocatalytic approach to synthesizing aliphatic and semi-aromatic copolyesters using Candida antarctica lipase B (CAL-B) as an eco-friendly catalyst. The study focused on selecting renewable monomers for medical applications, including succinate, adipate, and 2,5-furandicarboxylate derivatives, along with aliphatic diols (C=4-12) and dilinoleic diol (C=36). A two-step enzymatic polycondensation method was optimized to produce a library of three types of copolymers with tunable properties [2,3]. It was confirmed that from the wide range of copolyesters it was possible to select materials suitable for diverse medical applications, starting from drug delivery systems, electrospun scaffolds for tissue engineering to paper coatings for innovative medical device packaging. With the latter application, degradation both in aerobic composting and anaerobic digestion, and advanced characterization studies demonstrated that the developed materials are bio-degradable. The developed “green” polymers could open the door for the next generation of medical packaging and disposables and help improve hospital sustainability by facilitating a move towards a circular economy.

Acknowledgments
This work has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no. 872152 (GREEN MAP).

Lignin, the Earth's most prevalent aromatic biopolymer, comprises up to 30% of lignocellulosic biomass and is abundantly produced as a byproduct in pulp and paper and biorefinery industries.[1] Its inherent heterogeneity, amplified by harsh extraction methods, often leads to its use as a fuel source. However, lignin possesses significant potential for generating valuable low molecular weight compounds and functional materials.
This study introduces novel biocatalytic methods employing laccase-based systems to transform lignins into high-value products.[2,3] Kraft and organosolv lignins, both pristine and fractionated, were subjected to enzymatic oxidative treatments. Structural changes were evaluated using GPC, 31P NMR, and HSQC NMR analyses before and after each enzymatic step. The work highlights the critical role of the phenolic-to-aliphatic hydroxyl group ratio in dictating the catalytic pathway towards lignin modification. A high concentration of phenolic hydroxyl groups favors oxidative coupling, resulting in lignin polymerization and limited monomeric product release. Conversely, higher aliphatic hydroxyl content promotes depolymerization, significantly increasing the production of low molecular weight compounds in the aqueous medium.
Lastly, the low molecular weight products were identified and quantified by GC-MS analysis, and further modified using transferases via in-flow strategies. Subsequently, they were loaded into nanoparticles obtained from the oxidized lignin using a simple and scalable solvent precipitation method. The loading percentage, release profile, antioxidant, and antibacterial properties of the loaded molecules were determined.

Polymers in Liquid Formulations (PLFs) are essential in numerous everyday products, including cleaning agents, personal care items, agrochemicals, paints, and lubricants. Predominantly derived from fossil fuels, these polymers are non-biodegradable, contributing significantly to environmental pollution. The Royal Society of Chemistry estimates that over 36 million tonnes of PLFs are not recovered annually, presenting a substantial global environmental burden. Despite their societal and economic importance, there has been minimal coordinated effort to enhance the sustainability of PLFs. Our research addresses this critical issue by developing glycerol-based polyesters as sustainable alternatives. Glycerol, a byproduct of biomass processing, is highly functionalised, making it an ideal monomer for creating biodegradable and functional polymers. These polyesters, synthesised via lipase-catalysed polymerisation, offer amphiphilic balance and the potential for further functionalisation, improving their interaction with biological molecules and enhancing encapsulation efficiency.
These same glycerol-based polymers can also have an impact in the medical field where over 40% of active ingredients/drugs in development pipelines are poorly water-soluble, limiting their clinical applications. Encapsulating drugs in polymeric nanoparticles can enhance solubility, reduce toxicity, and ensure effective drug concentrations at target sites. Recent advancements in layer-by-layer additive manufacturing (AM) offer promising strategies for producing personalised medical devices. However, the limited availability of commercially viable polymers hinders the development of both AM for medicine and drug delivery.
These polyesters present a sustainable solution, offering biodegradability and functionality, thus addressing the urgent need for environmentally friendly PLFs. This innovative approach not only enhances drug delivery systems but also contributes to global sustainability efforts.

The conference will present different examples of PHA production in order to show how the choice of substrates integrated at the start of the biosynthesis process makes it possible to influence the chemical structure and the morphology of the PHA produced and thus to adjust the physico-chemical characteristics and the functional properties (thermal stability, mechanical behavior, viscosity, barrier properties, etc.). PHA are divided into two subgroups: short chain-length PHA (scl-PHA) composed of monomers of 3-5 carbon atoms, and medium chain-length PHA (mcl-PHA) composed of monomers of 6-14 carbon atoms. The physico-chemical properties drastically differ between the scl-PHA, that are rigid and brittle polymers and the mcl-PHA that are usually more rubbery and ductile.
Some results that we have recently obtained by different approaches illustrate the ability of certain PHA, mainly scl-PHA, to biodegrade in a very spectacular way in the marine environment. However, significant differences in behavior are observed with regard to the composition and morphology of the scl-PHA. The main factors intrinsic to PHA (chemical structure, molar mass, free volume, glass transition, mobility, crystallinity, solubility, hydrophilic/hydrophobic balance, etc.) play a determining role in their degradation. Additionally, in marine environment, understanding the mechanisms of biofouling is also a key issue for assessing the ecological impacts and the future of plastics. Assessments of polymer surface physical properties (hydrophobicity and roughness) combined with microbiological characterization of the biofilm (cell counts, taxonomy, composition and heterotrophic activity) can be performed using a wide range of techniques.

Biobased polymers are derived from renewable sources and are more sustainable than the current market-dominant fossil-based polymers. In this work, a series of biobased 2,5-bis(hydroxymethyl)furan (BHMF)-based polyesters were produced via a green and efficient bulk polymerization process by using either an enzyme (iCALB) or a commercially available catalyst (DBTO)¹. The number of methylene units in the aliphatic comonomer varied, and the influence of this variation on the thermal behavior and stability of the polymers was investigated. An oscillatory shear rheology investigation revealed significant differences in the melt behavior of the BHMF-based polyesters. A clear inversely proportional correlation between the low-frequency complex viscosity and the number of methylene units in the aliphatic segment was observed. Biodegradability tests revealed that the synthesized BHMF-based polyesters were biodegradable over time, with different biodegradation rates related to the length of the aliphatic segments in the repeating units.
These BHMF-based polyesters can be thermoreversibly crosslinked with a bismaleimide via Diels–Alder chemistry². This enables these covalent adaptable networks (CANs) to behave as thermosets with enhanced thermal and mechanical properties while transforming into processable and recyclable viscous liquids at higher temperatures.
This work emphasized that renewable BHMF-based polyesters can be produced via a solvent-free and sustainable process and that their biodegradability and thermal and rheological properties can be tailored. In conclusion, these polymers are very interesting materials that play a role in the circular plastic economy.

The future of plastics production is expected to at least partially shift towards a biological feedstock, necessitating the development of monomers derived from biological sources.
In this study, we aimed at synthesizing biobased thermosets/vitrimers starting from eugenol. The synthesis process involved a dimerization of eugenol followed by an epoxidation with 3-chloroperbenzoic acid (mCPBA) to yield the resulting diepoxy derivative, which served as a monomer. While the initial molecule originates from a biological source, the functionalization step relies on mCPBA, an halogenated petrochemical reagent that is also needed in an overstoichiometric amount, posing a clear discrepancy with the intended goal of enhancing sustainability.
To address this challenge, we developed a reaction procedure using an enzymatic pathway employing Candida antarctica lipase B. We anticipated this to be a more sustainable reaction pathway, also in terms of “green chemistry”. However, despite the environmental benefits, the enzymatic reaction exhibited drawbacks in terms of reaction time and heat requirements compared to the petrochemical counterpart. Evaluation of the reactions based on simpler concepts such as atom economy and E-factor favored the enzymatic approach. For a deeper dive, we conducted a comprehensive life cycle assessment (LCA) to assess the CO2 footprint of each reaction. This analysis incorporated environmental impacts of starting chemicals and energy consumption. Our results provide a direct comparison and identifies optimization parameters for further improvement of the monomer synthesis.