Study on extracellular hydrolases and their potential in aromatic polyester biodegradation
(2025) KBTM01 20251Biotechnology (MSc)
Biotechnology (M.Sc.Eng.)
- Abstract
- Plastic waste represents a major environmental challenge, with polyethylene terephthalate (PET) being one of the most widely used and recalcitrant polymers. Biodegradation offers a promising, mild alternative to conventional disposal and recycling methods. This study aimed to characterize extracellular hydrolases potentially involved in PET degradation, integrating both experimental and computational approaches. Four extracellular lipases were identified in Acinetobacter guillouiae, suggesting a role in its PET-degrading potential. Additional bacterial species, Pseudo-monas fluorescens, Rhodococcus opacus, and Cupriavidus metallidurans, were also evaluated, but none exhibited detectable PET degradation under the tested conditions. Focus... (More)
- Plastic waste represents a major environmental challenge, with polyethylene terephthalate (PET) being one of the most widely used and recalcitrant polymers. Biodegradation offers a promising, mild alternative to conventional disposal and recycling methods. This study aimed to characterize extracellular hydrolases potentially involved in PET degradation, integrating both experimental and computational approaches. Four extracellular lipases were identified in Acinetobacter guillouiae, suggesting a role in its PET-degrading potential. Additional bacterial species, Pseudo-monas fluorescens, Rhodococcus opacus, and Cupriavidus metallidurans, were also evaluated, but none exhibited detectable PET degradation under the tested conditions. Focus was placed on HiCut, a commercial hydrolase, to assess its thermostability and folding behaviour. HiCut retained activity after heat treatment, demonstrating the ability to refold and maintain function. Further-more, assays conducted in the presence of glycerol at 70 °C shown enhanced enzymatic activity, although molecular dynamics simulations revealed no significant difference in complex stability with or without glycerol. These findings provide insight into the biodegradation potential of A. guillouiae and position HiCut as a promising enzyme for further development, given its robust-ness and catalytic resilience, key properties for industrial applications in enzymatic PET degrada-tion. (Less)
- Popular Abstract
- Plastic has become a key material in our daily life, from packaging to keep our food fresh to the electronic devices we all depend on. Its strength, flexibility, and low cost have made it one of the most widely used materials in the world. However, plastic is a recalcitrant material: it can take centuries to fully degrade, posing a long-term environmental problem (Yang et al., 2024).
Our heavy use of single-use plastics has led to the production of large amounts of plastic waste, which is currently mainly disposed of in landfill sites. Over time, exposure to physical, chemical, and biological processes causes it to fragment into microplastics. These tiny particles that are increasingly being detected in landfill leachate, the liquid that... (More) - Plastic has become a key material in our daily life, from packaging to keep our food fresh to the electronic devices we all depend on. Its strength, flexibility, and low cost have made it one of the most widely used materials in the world. However, plastic is a recalcitrant material: it can take centuries to fully degrade, posing a long-term environmental problem (Yang et al., 2024).
Our heavy use of single-use plastics has led to the production of large amounts of plastic waste, which is currently mainly disposed of in landfill sites. Over time, exposure to physical, chemical, and biological processes causes it to fragment into microplastics. These tiny particles that are increasingly being detected in landfill leachate, the liquid that drains from these waste sites. Microplastics have been recognised as a significant threat to both ecosystems and human health. They often carry chemical additives like bisphenol A (BPA), a known endocrine disruptor that can interfere with hormone systems (Shen et al., 2022; Wojnowska-Baryła et al., 2022).
Alternatives have been developed to address the problem. One common method is incineration, which generates energy and heat but also releases greenhouse gases, contributing to climate change. Another option is recycling, which can significantly reduce carbon emissions and pollution by breaking plastics down, mechanically or chemically, into their basic components. However, recycling has its limits. Not all plastics are recyclable, and currently, less than 10% of global plastic waste is recycled (Yang et al., 2024). A promising alternative is biodegradation, which uses microorganisms and their enzymes to break down plastic polymers and utilize them as a source of carbon and energy. Gaining a deeper understanding of these microbes is key to identifying new plastic-degrading species. For example, PETase from Ideonella sakaiensis has shown encouraging results in degrading PET, one of the most common plastics (Yoshida et al., 2021).
My thesis focuses on advancing this field through the exploration of microbial plastic degradation and enzyme optimization. Specifically, I studied Acinetobacter guillouiae, a bacterial strain commonly found in wastewater treatment plants. This strain has shown partial PET-degrading capabilities, and enzymes involved in the process have been identified, offering promising leads for further research. In parallel, I investigated HiCut, a commercial fungal extracellular hydrolase that has demonstrated the ability to degrade PET and retain its enzymatic activity even after heat treatment. These microbial and enzymatic strategies offer exciting possibilities for developing scalable, eco-friendly solutions to manage plastic waste in the future. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9195692
- author
- Magnone, Anna LU
- supervisor
- organization
- course
- KBTM01 20251
- year
- 2025
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Hydrolase, PET, Plastic degradation, biotechnology
- language
- English
- id
- 9195692
- date added to LUP
- 2025-06-11 11:00:12
- date last changed
- 2025-06-11 11:00:12
@misc{9195692,
abstract = {{Plastic waste represents a major environmental challenge, with polyethylene terephthalate (PET) being one of the most widely used and recalcitrant polymers. Biodegradation offers a promising, mild alternative to conventional disposal and recycling methods. This study aimed to characterize extracellular hydrolases potentially involved in PET degradation, integrating both experimental and computational approaches. Four extracellular lipases were identified in Acinetobacter guillouiae, suggesting a role in its PET-degrading potential. Additional bacterial species, Pseudo-monas fluorescens, Rhodococcus opacus, and Cupriavidus metallidurans, were also evaluated, but none exhibited detectable PET degradation under the tested conditions. Focus was placed on HiCut, a commercial hydrolase, to assess its thermostability and folding behaviour. HiCut retained activity after heat treatment, demonstrating the ability to refold and maintain function. Further-more, assays conducted in the presence of glycerol at 70 °C shown enhanced enzymatic activity, although molecular dynamics simulations revealed no significant difference in complex stability with or without glycerol. These findings provide insight into the biodegradation potential of A. guillouiae and position HiCut as a promising enzyme for further development, given its robust-ness and catalytic resilience, key properties for industrial applications in enzymatic PET degrada-tion.}},
author = {{Magnone, Anna}},
language = {{eng}},
note = {{Student Paper}},
title = {{Study on extracellular hydrolases and their potential in aromatic polyester biodegradation}},
year = {{2025}},
}