Integrating biodegradable polyesters in a circular economy

Kalita, Naba Kumar; Hakkarainen, Minna

doi:10.1016/j.cogsc.2022.100751

Cited by 22 publications

(18 citation statements)

References 49 publications

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“…Lipases are present in a high majority of living organisms, with a large number of fungi also producing lipases . Tokiwa et al, demonstrated the ability of lipase to degrade synthetic polyesters, and Alejandra et al, confirmed lipase’s degradation capabilities in poly(3-hydroxybutyrate- co -4-hydroxybutyrate). , Ultimately, lipase is a readily available enzyme and shown to degrade polyesters. , Figure shows that lipase induces a trend in enzymatic hydrolysis near identical to that of proteinase K. The presence of the identical catalytic triad in both lipase and proteinase K may be the cause for the similar response, with both proteinase K and lipase exhibit the ‘catalytic triad of aspartic acid (Asp), histidine (His), and serine (Ser) . The catalytic triad catalyzes the nucleophilic attack on carbonyl carbons in esters using the active site serine. , While further work exploring wider enzyme structures may yield varied biodegradation capabilities, it is still important that both hydrolases have promoted activity on UV degraded polymers irrespective of individual enzymes.…”

Section: Resultsmentioning

confidence: 97%

“…35,36 Ultimately, lipase is a readily available enzyme and shown to degrade polyesters. 37,38 Figure 5 shows that lipase induces a trend in enzymatic hydrolysis near identical to that of proteinase K. The presence of the identical catalytic triad in both lipase and proteinase K may be the cause for the similar response, with both proteinase K and lipase exhibit the 'catalytic triad of aspartic acid (Asp), histidine (His), and serine (Ser). 39 The catalytic triad catalyzes the nucleophilic attack on carbonyl carbons in esters using the active site serine.…”

Section: Trends Utilizing Other Enzymesmentioning

confidence: 99%

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UV Light Degradation of Polylactic Acid Kickstarts Enzymatic Hydrolysis

Brown,

Badzinski,

Pardoe

et al. 2023

ACS Mater. Au

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Polylactic acid (PLA) and bioplastics alike have a designed degradability to avoid the environmental buildup that petroplastics have created. Yet, this designed biotic-degradation has typically been characterized in ideal conditions. This study seeks to relate the abiotic to the biotic degradation of PLA to accurately represent the degradation pathways bioplastics will encounter, supposing their improper disposal in the environment. Enzymatic hydrolysis was used to study the biodegradation of PLA with varying stages of photoaging. Utilizing a fluorescent tag to follow enzyme hydrolysis, it was determined that increasing the amount of irradiation yielded greater amounts of total enzymatic hydrolysis by proteinase K after 8 h of enzyme incubation. While photoaging of the polymers causes minimal changes in chemistry and increasing amounts of crystallinity, the trends in biotic degradation appear to primarily be driven by photoinduced reduction in molecular weight. The relationship between photoaging and enzyme hydrolysis appears to be independent of enzyme type, though commercial product degradation may be impacted by the presence of additives. Overall, this work reveals the importance of characterizing biodegradation with relevant samples that ultimately can inform optimization of production and disposal.

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Section: Resultsmentioning

confidence: 97%

Section: Trends Utilizing Other Enzymesmentioning

confidence: 99%

UV Light Degradation of Polylactic Acid Kickstarts Enzymatic Hydrolysis

Brown,

Badzinski,

Pardoe

et al. 2023

ACS Mater. Au

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“…PET recycling routes may be mechanical, chemical, or energetic [ 9 ]. Among them, chemical recycling emerges as a more interesting alternative because it prevents the deposition of solid waste in the environment, besides providing monomers to obtain new bottles and packaging [ 10 , 11 ]. The types of chemical recycling are glycolysis, methanolysis, aminolysis, ammonolysis, and hydrolysis.…”

Section: Introductionmentioning

confidence: 99%

Fungal Screening for Potential PET Depolymerization

et al. 2023

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Approximately 400 billion PET bottles are produced annually in the world, of which from 8 to 9 million tons are discarded in oceans. This requires developing strategies to urgently recycle them. PET recycling can be carried out using the microbial hydrolysis of polymers when monomers and oligomers are released. Exploring the metabolic activity of fungi is an environmentally friendly way to treat harmful polymeric waste and obtain the production of monomers. The present study addressed: (i) the investigation of potential of strains with the potential for the depolymerization of PET bottles from different manufacturers (crystallinity of 35.5 and 10.4%); (ii) the search for a culture medium that favors the depolymerization process; and (iii) gaining more knowledge on fungal enzymes that can be applied to PET recycling. Four strains (from 100 fungal strains) were found as promising for conversion into terephthalic acid from PET nanoparticles (npPET): Curvularia trifolii CBMAI 2111, Trichoderma sp. CBMAI 2071, Trichoderma atroviride CBMAI 2073, and Cladosporium cladosporioides CBMAI 2075. The fermentation assays in the presence of PET led to the release of terephthalic acid in concentrations above 12 ppm. Biodegradation was also confirmed using mass variation analyses (reducing mass), scanning electron microscopy (SEM) that showed evidence of material roughness, FTIR analysis that showed band modification, enzymatic activities detected for lipase, and esterase and cutinase, confirmed by monomers/oligomers quantification using high performance liquid chromatography (HPLC-UV). Based on the microbial strains PET depolymerization, the results are promising for the exploration of the selected microbial strain.

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“…Although there are important environmental incentives for plastic recycling, presorting of plastics before recycling is costly and time-consuming . As a substitute for some plastics that are not easy to recycle, especially single-use plastics that pose a threat to the environment, biodegradable polyesters have become a focus of attention. , Poly(lactic acid) (PLA), poly(butylene succinate) (PBS), and PBAT are the representative products of a biodegradable polyester. However, once the “biodegradable” end-product is thrown into the environment, it may not necessarily degrade due to the significant differences between the natural environment and compositing conditions …”

Section: Introductionmentioning

confidence: 99%

High-Molecular-Weight and Light-Colored Disulfide-Bond-Embedded Polyesters: Accelerated Hydrolysis Triggered by Redox Responsiveness

Hu,

Luan,

et al. 2023

Biomacromolecules

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Disulfide bonds have attracted considerable attention due to their reduction responsiveness, but it is crucial and challenging to prepare disulfide-bond-based polyesters by melt polycondensation. Herein, the inherently poor thermal stability of the S–S bond in melting polycondensation was overcome. Moreover, poly(butylene succinate-co-dithiodipropionate) (PBSDi) with a light color and high molecular weights (Mn values up to 84.7 kg/mol) was obtained. These polyesters can be applied via melt processing with T d,5% > 318 °C. PBSDi10-PBSDi40 shows good crystallizability (crystallinity 56–38%) and compact lamellar thickness (2.9–3.2 nm). Compared with commercial poly(butylene adipate-co-terephthalate) (PBAT), the elevated mechanical and barrier performances of PBSDi make them better packaging materials. For the degradation behavior, the disulfide monomer obviously accelerates the enzyme degradation but has a weaker effect on hydrolysis. In 0.1 mol/L or higher concentrations of H2O2 solutions, the oxidation of disulfide bonds to sulfoxide and sulfone groups can be realized. This process results in a stronger nucleophilic attack, as confirmed by the Fukui function and DFT calculations. Additionally, the greater polarity and hydrophilicity of oxidation products, proved by noncovalent interaction analysis, accelerate the hydrolysis of polyesters. Moreover, glutathione-responsive breakage, from polymers to oligomers, is confirmed by an accelerated decline in molecular weight. Our research offers fresh perspectives on the effective synthesis of the disulfide polyester and lays a solid basis for the creation of high-performance biodegradable polyesters that degrade on demand.

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Integrating biodegradable polyesters in a circular economy

Cited by 22 publications

References 49 publications

UV Light Degradation of Polylactic Acid Kickstarts Enzymatic Hydrolysis

UV Light Degradation of Polylactic Acid Kickstarts Enzymatic Hydrolysis

Fungal Screening for Potential PET Depolymerization

High-Molecular-Weight and Light-Colored Disulfide-Bond-Embedded Polyesters: Accelerated Hydrolysis Triggered by Redox Responsiveness

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