Parameter investigation for the development of an enzymatic plastic recycling technology
(2025) KBTM01 20251Biotechnology (MSc)
Biotechnology (M.Sc.Eng.)
- Abstract
- Traditional mechanical methods for the recycling of polyethylene terephthalate (PET) fail to produce high-quality materials suitable for upcycling. Alternatives like chemical recycling face challenges due to the high energy demands, concerns, and the cost of specialized equipment. Enzymatic recycling has emerged as a promising alternative, offering a simple process under environmentally friendly conditions and yielding pure monomers ready for repolymerization.
This thesis evaluated the production of seven PET hydrolases (PETases) in cost-effective media, obtaining yields up to 20 mg of enzyme per liter of cultivation. Temperature and time during recombinant protein induction were identified as key parameters to maximize the expression of... (More) - Traditional mechanical methods for the recycling of polyethylene terephthalate (PET) fail to produce high-quality materials suitable for upcycling. Alternatives like chemical recycling face challenges due to the high energy demands, concerns, and the cost of specialized equipment. Enzymatic recycling has emerged as a promising alternative, offering a simple process under environmentally friendly conditions and yielding pure monomers ready for repolymerization.
This thesis evaluated the production of seven PET hydrolases (PETases) in cost-effective media, obtaining yields up to 20 mg of enzyme per liter of cultivation. Temperature and time during recombinant protein induction were identified as key parameters to maximize the expression of the enzymes. The enzymatic depolymerization stage was optimized by identifying optimal temperature and pH. Final product recovery was achieved by precipitation, yielding a white fine powder with approximately 75% purity of the target monomer.
In addition to technical optimization, this work outlies key strategies to improve the industrial feasibility of the process, contributing to the advancement of sustainable PET upcycling. (Less) - Popular Abstract
- Current recycling technologies for polyethylene terephthalate (PET) tend to lower the quality of the recycled material, limiting its reuse in high-value applications. Enzymatic recycling offers a promising alternative. Enzymes are the catalysts of nature, carrying out all the chemical reactions that make life possible. This potential can be applied for recycling, as certain enzymes, known as PETases, are able to break down PET into its original building blocks under mild and environmentally friendly conditions. These building blocks can then be used to produce new plastic products of the same quality as virgin PET.
This thesis focused on optimizing key steps to make enzymatic recycling a more feasible and effective technology. Several... (More) - Current recycling technologies for polyethylene terephthalate (PET) tend to lower the quality of the recycled material, limiting its reuse in high-value applications. Enzymatic recycling offers a promising alternative. Enzymes are the catalysts of nature, carrying out all the chemical reactions that make life possible. This potential can be applied for recycling, as certain enzymes, known as PETases, are able to break down PET into its original building blocks under mild and environmentally friendly conditions. These building blocks can then be used to produce new plastic products of the same quality as virgin PET.
This thesis focused on optimizing key steps to make enzymatic recycling a more feasible and effective technology. Several approaches for enzyme production were evaluated, achieving good yields using a low-cost culture medium. In addition, the impact of factors such as temperature and pH on the breakdown of PET was studied, allowing the identification of conditions that maximize the recycling process. Once the plastic was degraded, a simple and efficient method was used to recover the resulting building blocks as a white fine powder, with promising purity levels.
To support the transition from a laboratory to an industrial setting, the project also addresses important aspects related to scalability and cost-efficiency. By outlining strategies to reduce production costs and improve process performance, these findings contribute to making enzymatic recycling a more competitive and sustainable alternative for tackling the global plastic waste problem. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9202103
- author
- Aristizabal Lanza, Lucia LU
- supervisor
- organization
- course
- KBTM01 20251
- year
- 2025
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- enzymatic recycling, PET, process parameters, scalability, biotechnology
- language
- English
- id
- 9202103
- date added to LUP
- 2025-06-19 10:19:05
- date last changed
- 2025-06-19 10:19:05
@misc{9202103,
abstract = {{Traditional mechanical methods for the recycling of polyethylene terephthalate (PET) fail to produce high-quality materials suitable for upcycling. Alternatives like chemical recycling face challenges due to the high energy demands, concerns, and the cost of specialized equipment. Enzymatic recycling has emerged as a promising alternative, offering a simple process under environmentally friendly conditions and yielding pure monomers ready for repolymerization.
This thesis evaluated the production of seven PET hydrolases (PETases) in cost-effective media, obtaining yields up to 20 mg of enzyme per liter of cultivation. Temperature and time during recombinant protein induction were identified as key parameters to maximize the expression of the enzymes. The enzymatic depolymerization stage was optimized by identifying optimal temperature and pH. Final product recovery was achieved by precipitation, yielding a white fine powder with approximately 75% purity of the target monomer.
In addition to technical optimization, this work outlies key strategies to improve the industrial feasibility of the process, contributing to the advancement of sustainable PET upcycling.}},
author = {{Aristizabal Lanza, Lucia}},
language = {{eng}},
note = {{Student Paper}},
title = {{Parameter investigation for the development of an enzymatic plastic recycling technology}},
year = {{2025}},
}