Addressing the problem of plastic waste: Development of an enzymatic process for PET recycling

Every day, media and NGOs describe the society\u27s disaffection for plastics accused of polluting the planet. All major brand-owners made commitments to solve this problem (e.g. Coca-Cola, Nestlé, Danone, PepsiCo, Suntory, Unilever, L’Oréal, Nike) and announced a future with less plastic waste by 2025. Nevertheless, only 6 years before the announced term, no effective solution is yet available to meet these goals. Indeed, existing technologies like thermo-mechanical recycling leads to loss in mechanical properties of the polymer and even if several chemical recycling processes are under development, they suffer from the disadvantages of using organic solvents, high reaction temperatures and the need of an intensive waste sorting. Consequently, enzymatic recycling appears as a pertinent solution notably because the enzyme selectivity avoids a drastic sorting of waste and enables the recycling of complex plastics (multi-layers construction in some bottles of sparkling water for instance), it is an eco-friendly reaction in water and because of savings in energy consumption due to a low temperature of reaction. Using a computer-aided engineering strategy, we drastically improved the depolymerizing performance of the best identified enzyme candidate. Utilizing site-directed mutagenesis targeted at the active site, combined with three-dimensional fold stabilization, we engineered an enzyme variant, demonstrating an astounding increase in thermostability combined with a high activity. This enzyme is able to depolymerize 90% of PET waste (200g/kg) into monomers, terephthalic acid and ethylene glycol, in less than 10 hours. The downstream processing was developed and optimized leading to the demonstration that this enzymatic technology could enable the use of an industrial plastic waste to produce again PET monomers and ultimately a bottle from this recycled PET. We hope to demonstrate the strong potential of the enzymatic technology jointly developed by CARBIOS and LISBP to provide a breakthrough solution to help solve society’s growing plastic waste problem

Surface acoustic wave driven ferromagnetic resonance in (Ga,Mn)(As,P) epilayers

Interdigitated transducers were used to generate and detect surface acoustic waves on a thin layer of (Ga,Mn)(As,P). The out-of-plane uniaxial magnetic anisotropy of this dilute magnetic semiconductor is very sensitive to the strain of the layer, making it an ideal test material for the dynamic control of magnetization via magneto-striction. The time-domain measurement of the amplitude and phase of the transmitted SAW during magnetic field sweeps indicated a clear resonant behavior at a field close to the one calculated to give a precession frequency equal to the SAW frequency. A resonance was observed from 5K to 85K, just below the Curie temperature of the layer. A full analytical treatment of the coupled magnetization/acoustic dynamics showed that the magneto-strictive coupling modifies the elastic constants of the material and accordingly the wave-vector solution to the elastic wave equation. The shape and position of the resonance were well reproduced by the calculations, in particular the fact that velocity (phase) variations resonated at lower fields than the acoustic attenuation variations

Addressing the problem of plastic waste: Development of an enzymatic process for PET recycling

International audienceEvery day, media and NGOs describe the society's disaffection for plastics accused of polluting the planet. All major brand-owners made commitments to solve this problem (e.g. Coca-Cola, Nestlé, Danone, PepsiCo, Suntory, Unilever, L’Oréal, Nike) and announced a future with less plastic waste by 2025.Nevertheless, only 6 years before the announced term, no effective solution is yet available to meet these goals. Indeed, existing technologies like thermo-mechanical recycling leads to loss in mechanical properties of the polymer and even if several chemical recycling processes are under development, they suffer from the disadvantages of using organic solvents, high reaction temperatures and the need of an intensive waste sorting. Consequently, enzymatic recycling appears as a pertinent solution notably because the enzyme selectivity avoids a drastic sorting of waste and enables the recycling of complex plastics (multi-layers construction in some bottles of sparkling water for instance), it is an eco-friendly reaction in water and because of savings in energy consumption due to a low temperature of reaction.Using a computer-aided engineering strategy, we drastically improved the depolymerizing performance of the best identified enzyme candidate. Utilizing site-directed mutagenesis targeted at the active site, combined with three-dimensional fold stabilization, we engineered an enzyme variant, demonstrating an astounding increase in thermostability combined with a high activity. This enzyme is able to depolymerize 90% of PET waste (200g/kg) into monomers, terephthalic acid and ethylene glycol, in less than 10 hours.The downstream processing was developed and optimized leading to the demonstration that this enzymatic technology could enable the use of an industrial plastic waste to produce again PET monomers and ultimately a bottle from this recycled PET.We hope to demonstrate the strong potential of the enzymatic technology jointly developed by CARBIOS and LISBP to provide a breakthrough solution to help solve society’s growing plastic waste problem

فوٹو فیچر

44-4

Dioxouranium(VI) Complexes with Sulphur Donor Schiff Bases Derived from Salicylaldehyde, Substituted Salicylaldehydes & 3-Aminothiophenol

634-63

Qualité du milieu marin littoral. Bulletin de la surveillance 2023. Laboratoire Environnement Ressources Boulogne-sur-Mer. Départements du Nord, du Pas-de-Calais et de la Somme

L’Ifremer coordonne, sur l’ensemble du littoral métropolitain, la mise en œuvre des réseaux d’observation et de surveillance de la mer côtière. Ce bulletin contient une synthèse et une analyse des données collectées par l’ensemble des réseaux pour les départements du Nord, du Pas-de-Calais et de la Somme. Des représentations graphiques homogènes (comparables à ceux des bulletins précédents comme à ceux des bulletins des autres départements français), assorties de commentaires, donnent des indications sur les niveaux et les tendances des paramètres mesurés