Polyethylene terephthalate (PET) fibers are characterized by exceptional mechanical strength, and textiles blended with cotton fibers combine both comfort and durability, showcasing widespread use in daily applications. However, improper disposal of discarded polyester-cotton textiles has resulted in severe environmental pollution, necessitating urgent and effective mitigation strategies. Enzymatic recycling of textiles offers superior environmental benefits and holds greater potential for industrial applications than alternative recycling methods. This study aims to explore a large-scale solution for the treatment of waste textiles, particularly addressing the challenge of resource recovery from polyester-cotton blended fabrics. An innovative enzymatic depolymerization process has been developed to achieve the recovery of high-purity terephthalic acid monomers. Experiments were conducted on three different textile blends with polyester-to-cotton ratios of 65/35, 70/30, and 80/20, and the influences of different colors on the process were investigated. Initially, the textiles were pretreated through mechanical grinding, which was followed by depolymerization of cotton fibers with commercial cellulase. The crystallinity of PET in the textiles was reduced through a rapid heating and cooling process. Subsequently, the PET was depolymerized by the engineered PET hydrolase. The results demonstrated that after decolorization and separation of terephthalic acid (TPA) from the reaction system, the monomer recovery rates for the three textile blends (65/35, 70/30, and 80/20) reached 90%, 91%, and 92%, respectively. Characterization analysis by nuclear magnetic resonance (NMR) confirmed that the purity of the recovered TPA was greater than 99%. In conclusion, the fully enzymatic recycling process developed in this study shows considerable promise for large-scale industrial applications and is anticipated to significantly advance the adoption and development of enzymatic recycling technologies for PET in industrial processes.
Phthalic Acids/chemistry* ; Polyesters/chemistry* ; Textiles ; Cotton Fiber ; Polyethylene Terephthalates/chemistry* ; Cellulase/chemistry* ; Recycling/methods* ; Polymerization

The discovery of new enzymes for poly(ethylene terephthalate) (PET) degradation has been a hot topic of research globally. Bis-(2-hydroxyethyl) terephthalate (BHET) is an intermediate compound in the degradation of PET and competes with PET for the substrate binding site of the PET-degrading enzyme, thereby inhibiting further degradation of PET. Discovery of new BHET degradation enzymes may contribute to improving the degradation efficiency of PET. In this paper, we discovered a hydrolase gene sle (ID: CP064192.1, 5085270-5086049) from Saccharothrix luteola, which can hydrolyze BHET into mono-(2-hydroxyethyl) terephthalate (MHET) and terephthalic acid (TPA). BHET hydrolase (Sle) was heterologously expressed in Escherichia coli using a recombinant plasmid, and the highest protein expression was achieved at a final concentration of 0.4 mmol/L of isopropyl-β-d-thiogalactoside (IPTG), an induction duration of 12 h and an induction temperature of 20 ℃. The recombinant Sle was purified by nickel affinity chromatography, anion exchange chromatography, and gel filtration chromatography, and its enzymatic properties were also characterized. The optimum temperature and pH of Sle were 35 ℃ and 8.0, and more than 80% of the enzyme activity could be maintained in the range of 25-35 ℃ and pH 7.0-9.0 and Co²⁺ could improve the enzyme activity. Sle belongs to the dienelactone hydrolase (DLH) superfamily and possesses the typical catalytic triad of the family, and the predicted catalytic sites are S129, D175, and H207. Finally, the enzyme was identified as a BHET degrading enzyme by high performance liquid chromatography (HPLC). This study provides a new enzyme resource for the efficient enzymatic degradation of PET plastics.
Actinomycetales/genetics* ; Hydrolases/metabolism* ; Phthalic Acids/chemistry* ; Polyethylene Terephthalates/metabolism*

Fermentation and induction conditions for recombinant Escherichia coli expressing Thermobifida fusca cutinase were optimized in flasks and 3L fermenter. Surface modification of poly (ethylene terephthalate) fibers with cutinase was also discussed. The results showed that, cutinase yield reached 128 U/mL by adding 2 g/L inducer lactose and 0.5% glycine. In the fed-batch culture in a 3 L fermenter, the maximum biomass cutinase activity was up to 506 U/mL, which is the highest bacterial cutinase activity reported by far. Recombinant cutinase was used to modify polyester fibers and terephthalic acid substance was detected by using UV analysis. The dyeing and wetting properties of cutinase treated fibers were higher than untreated fibers. Combined utilization of cutinase and Triton X-100 can significantly improve the hydrophilicity of polyester. This is the first report of surface modification on polyester fibers by bacterial cutinase.
Actinomycetales ; enzymology ; genetics ; Carboxylic Ester Hydrolases ; biosynthesis ; chemistry ; genetics ; Escherichia coli ; genetics ; metabolism ; Fermentation ; Polyethylene Glycols ; chemistry ; Polyethylene Terephthalates ; Recombinant Proteins ; biosynthesis ; genetics ; Surface Properties

This study sought to assess the effect of SspA on the formation of Staphylococcus aureus biofilm extending over the surfaces of Cardiovascular Biomaterial Dacron. SspA was extracted from the surface of staphylococcus aureus biofilm, purified, and then used to influence the adhesion of Staphylococcus aureus and the formation of Staphylococcus aureus biofilm on Dacron biomaterial surfaces. The formation of the Staphylococcus aureus biofilm on cardiovascular biomaterial Dacron surfaces under gradient SspA concentrations was evaluated by confocal laser microscopy. The result revealed that SspA inhibited the formation of Staphylococcus aureus biofilms on cardiovascular biomaterials surfaces effectively, and it was dose dependent. This study indicates that SspA is effective for preventing biomaterial centered infection and this method is conducive to clinical applications.
Bacterial Adhesion ; Biocompatible Materials ; chemistry ; Biofilms ; growth & development ; Polyethylene Terephthalates ; Prosthesis-Related Infections ; microbiology ; Serine Endopeptidases ; pharmacology ; Staphylococcus aureus ; pathogenicity ; physiology

The aim of this research was to evaluate the influence of steam sterilization on poly(ethylene glycol-terephthalate) and poly(butylene terephthalate) copolymer (PEGT/PBT) and its vascular cells compatibility, which was used as the scaffolds in vascular tissue engineering. Endothelial cells, smooth muscle cells and fibroblasts were cultured separately on the films after steam sterilization and after ultraviolet sterilization. These cells can grow well on the films after ultraviolet sterilization, while they can hardly adhere on steam sterilized films. Differential scanning calorimetry, static contact angle, X-ray photoelectron spectroscopy, surface carboxyl density quantity, H-nuclear magnetic resonance and scanning electronic microscope were employed to characterize the properties of poly(ether-esters) films before and after sterilization. These results showed that steam sterilization had little effect on the surface morphology and on the constitution of the copolymer, but the copolymer segments were redistributed during steam sterilization. The hydrophilic poly(ethylene glycol) (PEG) and the end carboxyl groups transferred from the bulk and enriched on the surface and the degree of crystallinity of hard segments increased slightly. Both the end carboxyl and PEG enriched on the surface can hinder the protein adhesion on the surface; so, lacking in receptor, the vascular cells cannot adhere on the films surfaces.
Biocompatible Materials ; chemistry ; Cell Adhesion ; Endothelial Cells ; cytology ; Humans ; Polyesters ; chemistry ; Polyethylene Glycols ; chemistry ; Polyethylene Terephthalates ; chemistry ; Steam ; Sterilization ; Surface Properties ; Umbilical Veins ; cytology

Diamond-like carbon (DLC) films were deposited by acetylene plasma immersion ion implantation-deposition (PIII-D) on biomedical polyethylene terephthalate (PET). The capacities of Staphylococcus aureus (SA), Staphylococcus epidermidis (SE), Escherichia coli (EC), Pseudomonas aeruginosa (PA) and Candida albicans (CA) for adhesion to PETs are quantitatively determined by the plate counting and Gamma-ray counting of 125I radio labeled bacteria in vitro. The results indicate that the capacities of five types of bacteria for adhesion to PETs are all suppressed by C2H2 PIII-D (P<0.05). The surface energy components of the various substrates and bacteria are calculated based on measurements in water, formamide and diiodomethane and Lifshitz-van del Waals/acid-base approach (LW-AB). The surface free energies obtained are used to calculate the interfacial free energies of adhesion (deltaF(adh)) of five kinds of bacteria on various substrates, and the results show that it is energetically unfavorable for bacterial adhesion to the DLC films already deposited on PET by C2H2 PIII-D.
Bacterial Adhesion ; drug effects ; physiology ; Carbon ; chemistry ; Coated Materials, Biocompatible ; chemistry ; Diamond ; chemistry ; Escherichia coli ; drug effects ; Heart Valve Prosthesis ; microbiology ; Materials Testing ; Polyethylene Terephthalates ; chemistry ; Staphylococcus aureus ; drug effects ; Staphylococcus epidermidis ; drug effects

In this study for exploring the effect of RGD peptide on adhesive stability of endothelial cells biomaterial surface, all materials were divided into three groups, RGD group (PET covalently grafted synthetic RGD peptides), control group (PET precoated with fibronectin) and blank group (Non-coated surface). Cultured human umbilical vein endothelial cells (HUVECs) were seeded on the materials, then adhesive stability of HUVECs on the varied PET surfaces was observed under steady flow condition, and effects of shear stress and shear time on adherent cells were compared. The results showed that the resistance adherent endothelial cells to detachment by flow was shear stress and shear time dependent. Comparison three groups under the same condition revealed that the ECs retention rates of RGD-grafted or fibronectin-coated group were much higher than that of the non-coated group. Under 8.19 dyne/cm2 shear stress after 4h, retention rates were 13.73% (blank group), 43.33% (RGD group) and 40.75% (control group) respectively. These data indicated that RGD peptide can improve the adhesive stability of endothelial cell on biomaterial and the effect of RGD in vivo needs further studies.
Biocompatible Materials ; chemistry ; Cell Adhesion ; Human Umbilical Vein Endothelial Cells ; cytology ; Humans ; Oligopeptides ; chemistry ; Polyethylene Terephthalates ; chemistry ; Stress, Mechanical

In this paper, polyethylene glycol (PEG) of different molecular weight was grafted on the polyethylene terephthalate (PET, Dacron) films by plasma surface grafting modification. The competitive adsorption relation of plasma (fibrinogen and albumin) adsorbing on materials surface was analyzed in light of surface energy and interface free energy. The results indicated that the PET films grafted PEG long chain molecular possesses the characteristic of preferentially adsorbing albumin and this adsorption tendency of grafted PEG6000 sample is most distinct. The platelet adhesion tests of the PET films whose surfaces were pre-set in contact with fibrinogen and albumin indicated that the surface adsorbing albumin can distinctly inhibit platelet adhesion and aggregation and possess favorable blood compatibility, but the surface adsorbing fibrinogen can enhance platelet adhesion and aggregation.
Adsorption ; Biocompatible Materials ; chemistry ; Humans ; Plasma ; Platelet Adhesiveness ; Polyethylene Glycols ; chemistry ; Polyethylene Terephthalates ; chemistry ; Serum Albumin ; Surface Properties

The aim of this experiment is to graft synthesizing Arg-Gly-Asp peptides (RGD) on the surface of polymer materials, combine endothelial cells with its special site, enhance the adhesion of endothelial cells on the surface, promote the blood compatibility of the biomaterials. Carboxy group (-COOH) was grafted on the materials surface by ultraviolet (UV) radiation, and the RGD serial obtained by liquid phase synthesis was successfully grafted on the disposed materials by chemical reaction. The endothelialization experiment was made also. The grafting results were measured by X-ray photoelectron spectroscopy (XPS), and endothelialization was observed using optical microscope and scanning electron microscope (SEM). The results indicated that the method improves the effect of materials endothelialization. The experiment has made successful use of UV grafting and chemical coupling methods to graft bioactive RGD onto PET film surface. This is a new method of grafting bioactive peptide.
Biocompatible Materials ; chemistry ; Cells, Cultured ; Cells, Immobilized ; Endothelium ; cytology ; drug effects ; Humans ; Oligopeptides ; chemical synthesis ; chemistry ; pharmacology ; Polyethylene Terephthalates ; chemistry ; Surface Properties