Averous L

References (5)

Title : Enzymatic recycling of thermoplastic polyurethanes: Synergistic effect of an esterase and an amidase and recovery of building blocks - Magnin_2019_Waste.Manag_85_141
Author(s) : Magnin A , Pollet E , Perrin R , Ullmann C , Persillon C , Phalip V , Averous L
Ref : Waste Manag , 85 :141 , 2019
Abstract : Biological recycling of polyurethanes (PU) is a huge challenge to take up in order to reduce a large part of the environmental pollution from these materials. However, enzymatic depolymerization of PU still needs to be improved to propose valuable and green solutions. The present study aims to identify efficient PU degrading enzymes among a collection of 50 hydrolases. Screenings based on model molecules were performed leading to the selection of an efficient amidase (E4143) able to hydrolyze the urethane bond of a low molar mass molecule and an esterase (E3576) able to hydrolyze a waterborne polyester polyurethane dispersion. Degradation activities of the amidase, the esterase and a mix of these enzymes were then evaluated on four thermoplastic polyurethanes (TPU) specifically designed for this assay. The highest degradation was obtained on a polycaprolactone polyol-based polyurethane with weight loss of 33% after 51 days measured for the esterase. Deep cracks on the polymer surface observed by scanning electron microscopy and the presence of oligomers on the remaining TPU detected by size exclusion chromatography evidenced the polymer degradation. Mixing both enzymes led to an increased amount of urethane bonds hydrolysis of the polymer. 6-hydroxycaproic acid and 4,4'-methylene dianiline were recovered after depolymerization as hydrolysis products. Such building blocks could get a second life with the synthesis of new macromolecular architectures.
ESTHER : Magnin_2019_Waste.Manag_85_141
PubMedSearch : Magnin_2019_Waste.Manag_85_141
PubMedID: 30803567

Title : Biotic and Abiotic Synthesis of Renewable Aliphatic Polyesters from Short Building Blocks Obtained from Biotechnology - Debuissy_2018_ChemSusChem_11_3836
Author(s) : Debuissy T , Pollet E , Averous L
Ref : ChemSusChem , 11 :3836 , 2018
Abstract : Biobased polymers have seen their attractiveness increase in recent decades thanks to the significant development of biorefineries to allow access to a wide variety of biobased building blocks. Polyesters are one of the best examples of the development of biobased polymers because most of them now have their monomers produced from renewable resources and are biodegradable. Currently, these polyesters are mainly produced by using traditional chemical catalysts and harsh conditions, but recently greener pathways with nontoxic enzymes as biocatalysts and mild conditions have shown great potential. Bacterial polyesters, such as poly(hydroxyalkanoate)s (PHA), are the best example of the biotic production of high molar mass polymers. PHAs display a wide variety of macromolecular architectures, which allow a large range of applications. The present contribution aims to provide an overview of recent progress in studies on biobased polyesters, especially those made from short building blocks, synthesized through step-growth polymerization. In addition, some important technical aspects of their syntheses through biotic or abiotic pathways have been detailed.
ESTHER : Debuissy_2018_ChemSusChem_11_3836
PubMedSearch : Debuissy_2018_ChemSusChem_11_3836
PubMedID: 30203918

Title : Enzymatic Synthesis of Amino Acids Endcapped Polycaprolactone: A Green Route Towards Functional Polyesters - Duchiron_2018_Molecules_23_
Author(s) : Duchiron SW , Pollet E , Givry S , Averous L
Ref : Molecules , 23 : , 2018
Abstract : sigma-caprolactone (CL) has been enzymatically polymerized using alpha-amino acids based on sulfur (methionine and cysteine) as (co-)initiators and immobilized lipase B of Candida antarctica (CALB) as biocatalyst. In-depth characterizations allowed determining the corresponding involved mechanisms and the polymers thermal properties. Two synthetic strategies were tested, a first one with direct polymerization of CL with the native amino acids and a second one involving the use of an amino acid with protected functional groups. The first route showed that mainly polycaprolactone (PCL) homopolymer could be obtained and highlighted the lack of reactivity of the unmodified amino acids due to poor solubility and affinity with the lipase active site. The second strategy based on protected cysteine showed higher monomer conversion, with the amino acids acting as (co-)initiators, but their insertion along the PCL chains remained limited to chain endcapping. These results thus showed the possibility to synthesize enzymatically polycaprolactone-based chains bearing amino acids units. Such cysteine endcapped PCL materials could then find application in the biomedical field. Indeed, subsequent functionalization of these polyesters with drugs or bioactive molecules can be obtained, by derivatization of the amino acids, after removal of the protecting group.
ESTHER : Duchiron_2018_Molecules_23_
PubMedSearch : Duchiron_2018_Molecules_23_
PubMedID: 29385763

Title : Nanoclays for Lipase Immobilization: Biocatalyst Characterization and Activity in Polyester Synthesis - Ozturk_2016_Polymers.(Basel)_8_
Author(s) : Ozturk H , Pollet E , Phalip V , Guvenilir Y , Averous L
Ref : Polymers (Basel) , 8 : , 2016
Abstract : The immobilization of Candida antarctica lipase B (CALB) was performed by physical adsorption on both neat and organo-modified forms of sepiolite and montmorillonite. The influence of different parameters, e.g., solvent, enzyme loading, cross-linking, and type of clay support, on immobilization efficiency and catalyst hydrolytic activity has been investigated. The highest hydrolytic activities were obtained for CALB immobilized on organo-modified clay minerals, highlighting the beneficial effect of organo-modification. The esterification activity of these CALB/organoclay catalysts was also tested in the ring-opening polymerization of sigma-caprolactone. The polymerization kinetics observed for clay-immobilized catalysts confirmed that CALB adsorbed on organo-modified montmorillonite (CALB/MMTMOD) was the highest-performing catalytic system.
ESTHER : Ozturk_2016_Polymers.(Basel)_8_
PubMedSearch : Ozturk_2016_Polymers.(Basel)_8_
PubMedID: 30974694

Title : Enzymatic Synthesis of a Bio-Based Copolyester from Poly(butylene succinate) and Poly((R)-3-hydroxybutyrate): Study of Reaction Parameters on the Transesterification Rate - Debuissy_2016_Biomacromolecules_17_4054
Author(s) : Debuissy T , Pollet E , Averous L
Ref : Biomacromolecules , 17 :4054 , 2016
Abstract : The enzyme-catalyzed synthesis of fully biobased poly(3-hydroxybutyrate-co-butylene succinate) (poly(HB-co-BS)) copolyesters is reported for the first time. Different Candida antarctica lipase B (CALB)-catalyzed copolyesters were produced in solution, via a one-step or a two-step process from 1,4-butanediol, diethyl succinate, and synthesized telechelic hydroxylated poly(3-hydroxybutyrate) oligomers (PHB-diol). The influence of the ester/hydroxyl functionality ratio, catalyst amount, PHB-diol oligomer chain length, hydroxybutyrate (HB) and butylene succinate (BS) contents, and the nature of the solvent were investigated. The two-step process allowed the synthesis of copolyesters of high molar masses (Mn up to 18000 g/mol), compared to the one-step process (Mn approximately 8000 g/mol), without thermal degradation. The highest molar masses were obtained with diphenyl ether as solvent, compared with dibenzyl ether or anisole. During the two-step process, the transesterification rate between the HB and BS segments (i) increased with increasing amount of catalyst and decreasing molar mass of the PHB-diol oligomer, (ii) decreased when anisole was used as the solvent, and (iii) was not influenced by the HB/BS ratio. Tendencies toward block or random macromolecular architectures were observed as a function of the reaction time, the PHB-diol oligomer chain length, and the chosen solvent. Immobilized CALB-catalyzed copolyesters were thermally stable up to 200 degrees C. The crystalline structure of the poly(HB-co-BS) copolyesters depended on the HB/BS ratio and the average sequence length of the segments. The crystalline content, Tm and Tc decreased with increasing HB content and the randomness of the copolymer structure.
ESTHER : Debuissy_2016_Biomacromolecules_17_4054
PubMedSearch : Debuissy_2016_Biomacromolecules_17_4054
PubMedID: 27936726