Abstract
Enzymatic depolymerization of poly(ethylene terephthalate) (PET) has emerged as a potential method for PET recycling, but extensive thermomechanical preprocessing to reduce both the crystallinity and particle size of PET is often conducted, which is costly and energy-intensive. In the current work, we use high-crystallinity PET (HC-PET) and low-crystallinity cryomilled PET (CM-PET) with three distinct particle size distributions to investigate the effect of PET particle size and crystallinity on the performance of a variant of the leaf compost-cutinase enzyme (LCC-ICCG). We show that LCC-ICCG hydrolyzes PET, resulting in the accumulation of terephthalic acid and, interestingly, also releases significant amount of mono(2-hydroxyethyl)terephthalate. Particle size reduction of PET increased the maximum rate of reaction for HC-PET, while the maximum hydrolysis rate for CM-PET was not significantly different across particle sizes. For both substrates, however, we show that particle size reduction has little effect on the overall conversion extent. Specifically, the CM-PET film was converted to 99 ± 0.2% mass loss within 48 h, while the HC-PET powder reached only 23.5 ± 0.0% conversion in 144 h. Overall, these results suggest that amorphization of PET is a necessary pretreatment step for enzymatic PET recycling using the LCC-ICCG enzyme but that particle size reduction may not be required.
Original language | American English |
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Pages (from-to) | 9131-9140 |
Number of pages | 10 |
Journal | ACS Sustainable Chemistry and Engineering |
Volume | 10 |
Issue number | 28 |
DOIs | |
State | Published - 2022 |
Bibliographical note
Publisher Copyright:© 2022 American Chemical Society. All rights reserved.
NREL Publication Number
- NREL/JA-2A00-83351
Keywords
- crystallinity
- cutinase
- interfacial biocatalysis
- kinetics
- particle size
- plastic recycling