Highly Selective Enzymatic Recovery of Building Blocks from Wool-Cotton-Polyester Textile Waste Blends

Quartinello, Felice; Vecchiato, Sara; Weinberger, Simone; Kremenser, Klemens; Skopek, Lukas; Pellis, Alessandro; Guebitz, Georg M.

doi:10.3390/polym10101107

Cited by 48 publications

(30 citation statements)

References 36 publications

(40 reference statements)

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“…Given that natural microbial systems evolved over millions of years to optimally degrade recalcitrant polymers, perhaps it is thus not surprising, in hindsight, that a soil bacterium such as I. sakaiensis evolved the ability to utilize a crystalline polyester substrate with, to our collective knowledge, a two-enzyme system ( 10 , 16 ). Extending the analogy of cellulase enzymes and plant cell wall deconstruction for breaking down diverse polysaccharides simultaneously, the concept of deconstructing synthetic polymers in the form of mixed plastics waste with advanced enzyme mixtures is an exciting research direction beyond PET to other polyesters, natural fibers (e.g., cellulose from cotton, proteins from wool) ( 70 ), polyamides, polyurethanes ( 71 ), and other polymers susceptible to enzymatic depolymerization. Going forward, the design of multienzyme systems for depolymerization of mixed polymer wastes is a promising and fruitful area for continued investigation.…”

Section: Discussionmentioning

confidence: 99%

Characterization and engineering of a two-enzyme system for plastics depolymerization

Knott

Erickson

Allen

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

307

320

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Plastics pollution represents a global environmental crisis. In response, microbes are evolving the capacity to utilize synthetic polymers as carbon and energy sources. Recently, Ideonella sakaiensis was reported to secrete a two-enzyme system to deconstruct polyethylene terephthalate (PET) to its constituent monomers. Specifically, the I. sakaiensis PETase depolymerizes PET, liberating soluble products, including mono(2-hydroxyethyl) terephthalate (MHET), which is cleaved to terephthalic acid and ethylene glycol by MHETase. Here, we report a 1.6 Å resolution MHETase structure, illustrating that the MHETase core domain is similar to PETase, capped by a lid domain. Simulations of the catalytic itinerary predict that MHETase follows the canonical two-step serine hydrolase mechanism. Bioinformatics analysis suggests that MHETase evolved from ferulic acid esterases, and two homologous enzymes are shown to exhibit MHET turnover. Analysis of the two homologous enzymes and the MHETase S131G mutant demonstrates the importance of this residue for accommodation of MHET in the active site. We also demonstrate that the MHETase lid is crucial for hydrolysis of MHET and, furthermore, that MHETase does not turnover mono(2-hydroxyethyl)-furanoate or mono(2-hydroxyethyl)-isophthalate. A highly synergistic relationship between PETase and MHETase was observed for the conversion of amorphous PET film to monomers across all nonzero MHETase concentrations tested. Finally, we compare the performance of MHETase:PETase chimeric proteins of varying linker lengths, which all exhibit improved PET and MHET turnover relative to the free enzymes. Together, these results offer insights into the two-enzyme PET depolymerization system and will inform future efforts in the biological deconstruction and upcycling of mixed plastics.

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Section: Discussionmentioning

confidence: 99%

Characterization and engineering of a two-enzyme system for plastics depolymerization

Knott

Erickson

Allen

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

307

320

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“…However, there is a breed of sheep that are specifically raised for their milk and to produce cheese—wool derived from this industry is not suitable for the textile sector. In consequence, the wool coming from this activity is considered a by-product [26,27,28,29,30]. Additionally, low material cost, biodegradability and the low energy required for processing make natural fibers a good replacement for conventional synthetic fibers such as carbon or glass fibers, from both an economic and environmental point of view.…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, low material cost, biodegradability and the low energy required for processing make natural fibers a good replacement for conventional synthetic fibers such as carbon or glass fibers, from both an economic and environmental point of view. However, bio-origin fibers often present significantly lower mechanical properties or higher water uptake compared to synthetic fibers, which can be enhanced by fiber surface modification [5,17,29,31,32]. The hydrophilic surface of wool fibers needs to be chemically modified in order to improve compatibility with a hydrophobic polymer matrix.…”

Section: Introductionmentioning

confidence: 99%

Effect of Different Compatibilizers on Injection-Molded Green Fiber-Reinforced Polymers Based on Poly(lactic acid)-Maleinized Linseed Oil System and Sheep Wool

2019

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A method to modify polymers is that of introducing fibers in a matrix to produce a fiber-reinforced polymer (FRP). Consequently, the aim of this work was to study the compatibility effect of four coupling agents on wool FRP properties, using poly(lactic acid) plasticized with maleinized linseed oil as polymer matrix. The content of wool assessed was 1 phr. The compatibilizers were (3-(2-aminoethylamino)propyl)-trimethoxysilane, trimethoxy (2-(7-oxabicyclo (4.1.0)hept-3-yl) ethyl) silane, tris(2-methoxyethoxy)(vinyl) silane and titanium (IV) (triethanolaminate)isopropoxide. Initially, wool was modified with coupling agents in an acetone/water (50/50) solution. Mechanical properties were evaluated by tensile and flexural properties, hardness by Shore D measurement and impact resistance by Charpy’s energy. Differential scanning calorimetry, dynamic thermo-mechanical analysis, and thermogravimetric analysis were conducted to evaluate the interaction among components and the effect of the coupling agents on the thermal properties of the original material. Color, wettability and scanning electron microscopy were used to describe physical and microstructural properties. Modification of fibers allows achieving improved mechanical properties and changes the thermal properties of the FRPs slightly. Coupling agent treatment helps to formulate PLA–MLO and sheep wool materials and to improve their performance, thereby creating a broader spectrum of applications for PLA maintaining the bio-based character of the material.

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“…As demonstrated by Watanabe (Watanabe and Sakai, 2003), the major emission of brominated and chlorinated compounds occurs directly during production. Moreover, the amount of landfilled and incinerated textiles per years also constitutes a problem for the environment (Quartinello et al, 2018). Most of the FRC are absorbed on surface material, therefore their leaching and consequently accumulation, cause major health risks also for marine environment and in the end also for human health due to their dietary.…”

Section: Introductionmentioning

confidence: 99%

Increased Flame Retardancy of Enzymatic Functionalized PET and Nylon Fabrics via DNA Immobilization

et al. 2019

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Poly(ethylene terephthalate) (PET) and nylon find their main applications in working clothes, domestic furniture and as indoor decoration (curtains and carpets). The increasing attention on healthy lifestyle, together with protection and safety, gained a strong interest in today's society. In this context, reducing the flammability of textiles has been tackled by designing flame retardants (FRs) able to suppress or delay the flame propagation. Commercially available FRs for textiles often consist of brominated, chlorinated and organo-phosphorus compounds, which are considered a great concern for human health and for the environment. In this study, Deoxyribose Nucleic Acid (DNA) was investigated as a green and eco-friendly alternative to halogen-containing FRs. DNA is in fact able to provide flame retardant properties due to its intrinsically intumescent building blocks (deoxyribose, phosphoric-polyphosphoric acid, and nitrogen-containing bases). In a first step, anchor groups (i.e., carboxyl groups) for subsequent coupling of DNA were introduced to PET and nylon-6 fabrics via limited surface hydrolysis with Humicola insolens cutinase (HiC). Released monomer/oligomers were measured via HPLC (1 mM of BHET for PET and 0.07 mM of caprolactam from nylon after 72 h). In a next step, DNA immobilization on the activated polymers was studied by using three different coupling systems, namely: EDC/NHS, dopamine, and tyrosine. DNA coupling was confirmed via FT-IR that showed typical bands at 1,220, 970, and 840 cm−1. The tyrosine/DNA coupling on nylon fabrics resulted to be the most effective as certified by the lowest burning rate and total burning time (35 s, 150 mm, and 4.3 mm*s−1 for the blank and 3.5 s, 17.5 mm, and 5 mm* s−1 for nylon/tyrosine/DNA) which was also confirmed by FT-IR and ESEM/EDS measurements. Thermogravimetric analysis (TGA) further confirmed that tyrosine/DNA coated nylon showed a lower thermal degradation between 450 and 625°C when compared to the untreated samples.

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Highly Selective Enzymatic Recovery of Building Blocks from Wool-Cotton-Polyester Textile Waste Blends

Cited by 48 publications

References 36 publications

Characterization and engineering of a two-enzyme system for plastics depolymerization

Characterization and engineering of a two-enzyme system for plastics depolymerization

Effect of Different Compatibilizers on Injection-Molded Green Fiber-Reinforced Polymers Based on Poly(lactic acid)-Maleinized Linseed Oil System and Sheep Wool

Increased Flame Retardancy of Enzymatic Functionalized PET and Nylon Fabrics via DNA Immobilization

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