Enzymatic recovery of polyester building blocks from polymer blends

• Published in: Process biochemistry (1991) Vol. 59; pp. 58 - 64
• Main Authors: Gamerith, Caroline, Zartl, Barbara, Pellis, Alessandro, Guillamot, Frédérique, Marty, Alain, Acero, Enrique Herrero, Guebitz, Georg M.
• Format: Journal Article
• Language: English
• Published: Barking Elsevier Ltd 01.08.2017; Elsevier BV
• Subjects: Bottles; Calorimetry; Crystal structure; Cutinase; Differential scanning calorimetry; Enzymatic polymer recycling; Enzymes; Fourier transforms; Hydrolysis; Infrared spectroscopy; Packaging; Particle size; Poly (ethylene terephthalate); Polyesters; Polyethylene; Polyethylene terephthalate; Polymer blends; Powder; Product inhibition; Recycling; Temperature; Terephthalic acid; Thermobifida cellulosilytica; Cutinase; Polymer blends; Enzymatic polymer recycling; Thermobifida cellulosilytica; Poly (ethylene terephthalate)
• ISSN: 1359-5113; 1873-3298
• DOI: 10.1016/j.procbio.2017.01.004

[Display omitted] •Thc_Cut1 hydrolyzes PET in polymer blends without prior separation.•Significant inhibitory effect of soluble released products is detectable.•Main process influencing factors are particle size, temperature & enzyme stability. In this study we investigated the ability of a cutinase from Thermobifida cellulosilytica (Thc_Cut1) to hydrolyze poly (ethylene terephthalate) (PET) moieties in different polymer blends. The composition of various materials including commercial available bottles and packaging was determined using Fourier Transform InfraRed spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC). When incubated with PET blended with polyethylene (PE) or polyamide (PA) from packaging and bottles without prior separation, Thc_Cut1 selectively hydrolyzed the PET moieties releasing terephthalic acid (TPA) and mono(2-hydroxyethyl) terephthalate (MHET). Polymer blends were hydrolyzed in an up to 9 times higher extent compared to higher crystalline pure PET. The influence of various parameters like temperature, particle size, crystallinity and product inhibition on hydrolysis of PET moieties by Thc_Cut1 was investigated. The amount of products released was up to 10 times higher when the incubation temperature was increased from 40°C to 60°C. The smaller the particle size the higher the hydrolysis rates were. Interestingly, semi-crystalline (24%) PET from bottles was hydrolyzed faster than powder from amorphous PET films (12%). An inhibitory effect of bis(2-hydroxyethyl) terephthalate (BHET) on hydrolysis of PET by Thc_Cut1 was observed.