Synergistic chemo‐enzymatic hydrolysis of poly(ethylene terephthalate) from textile waste

Abstract

SummaryDue to the rising global environment protection awareness, recycling strategies that comply with the circular economy principles are needed. Polyesters are among the most used materials in the textile industry; therefore, achieving a complete poly(ethylene terephthalate) (PET) hydrolysis in an environmentally friendly way is a current challenge. In this work, a chemo‐enzymatic treatment was developed to recover the PET building blocks, namely terephthalic acid (TA) and ethylene glycol. To monitor the monomer and oligomer content in solid samples, a Fourier‐transformed Raman method was successfully developed. A shift of the free carboxylic groups (1632 cm−1) of TA into the deprotonated state (1604 and 1398 cm−1) was observed and bands at 1728 and 1398 cm−1 were used to assess purity of TA after the chemo‐enzymatic PET hydrolysis. The chemical treatment, performed under neutral conditions (T = 250 °C, P = 40 bar), led to conversion of PET into 85% TA and small oligomers. The latter were hydrolysed in a second step using the Humicola insolens cutinase (HiC) yielding 97% pure TA, therefore comparable with the commercial synthesis‐grade TA (98%).

Shotgun proteomics reveals putative polyesterases in the secretome of the rock-inhabiting fungus Knufia chersonesos

“…The samples were centrifuged at 18.213 x g (5427 R, Eppendorf) for 15 min at 4 °C, then filtered through 0.45 μm nylon syringe filters and thereafter analysed by a HPLC-DAD system consisting of a 1290 Infinity II LC (Agilent Technologies), coupled with a reversed phase column C18 (Poroshell 120 EC-C18 2,7 µm 3.0 × 150 mm), at a flow rate of 0.4 mL/min 15,19 . The PBAT hydrolysis products were separated using a nonlinear gradient according to Quartinello et al 2 with some modifications (i.e. solvent A: H 2 O, solvent B: methanol, solvent C: formic acid; solvent C was kept at 10% constantly; 0-13 min 15% B; 13-30 min 15-40% B; 30-35 min 40-90% B; 35-46 min 90-15% B; 46-60 min 15% B) and detected with a photodiode array detector (Agilent Technologies) at the wavelength of 245 nm.…”

“…Synthetic polymeric materials such as polyesters are ubiquitously present in our daily life because of their numerous applications 1,2 . The high production rate together with their resistance to environmental influences and recalcitrance to microbial attacks, has however strongly contributed to their undesirable accumulation in nature and hence to environmental and waste management issues 3 .…”

Biocatalytic Degradation Efficiency of Postconsumer Polyethylene Terephthalate Packaging Determined by Their Polymer Microstructures

“…For determination of the 1 H signal of the β CH 2 protons for the hydroxyl end group, its 13 C satellite at the low-field side was not involved in the calculation due to their heavily overlapping with the strong main signal of the CH proton in HFIP (a septet centered at 4.41 ppm). The data were recorded with 256 or 1024 scans and a recycle delay of 15 s. A twofold zero-filled to 128k points and an exponential line broadening of 0.2 Hz was applied to data processing.…”

“…[7b,10-11] This is due to a high glass transition temperature of PET of around 75 °C where the amorphous PET domains gain enough mobility to be readily accessed by the enzyme. Although a pretreatment at high temperature (250 °C) and pressure (39 bars) could convert highly crystalline PET fibers into biodegradable oligomers, [13] this process was much more energy consuming than an enzymatic hydrolysis of postconsumer PET materials. [10][11][12] These previous studies indicated that the high degree of crystallinity above 20% of PET bottles and fibers was correlated with a considerably low enzymatic degradation rate.…”

High Throughput Screening for New Fungal Polyester Hydrolyzing Enzymes

“…For analysis of the samples, a HPLC-DAD system consisting of a 1260 Infinity (Agilent Technologies, Palo Alto, CA, United States) coupled with a reversed phase column C18 (Poroshell 120 EC-C18 2,7 µm 3.0 × 150 mm) was used. The PBAT hydrolysis products were separated using a non-linear gradient as previously described (Quartinello et al, 2017) and detected with a photodiode array detector (Agilent Technologies, 1290 Infinity II, Vienna, Austria) at the wavelength of 245 nm. For the quantification of the released products bis(4-hydroxybutyl) terephthalate (BTaB), mono(4hydroxybutyl) terephthalate (BTa) and terephthalic acid (Ta) (BASF, Ludwigshafen am Rhein, Deutschland), was used.…”