Immobilization of PETase enzymes on magnetic iron oxide nanoparticles for the decomposition of microplastic PET

Schwaminger, Sebastian P.; Fehn, Stefan; Steegmüller, Tobias; Rauwolf, Stefan; Löwe, Hannes; Pflüger‐Grau, Katharina; Berensmeier, Sonja

doi:10.1039/d1na00243k

Cited by 52 publications

(39 citation statements)

References 56 publications

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“…When stored at 4 °C or room temperature for 30 days, BIND-PETase showed no significant change in enzyme activity (Figure S8A) (Student’s t test, p > 0.05). The storage stability of BIND-PETase surpassed the PETase enzyme immobilized on magnetic iron oxide nanoparticles, which had 40%–70% loss of its enzyme activity during 2 week storage at 4 °C . In addition, the whole-cell BIND-PETase biocatalyst could be recovered from the reaction solution by centrifugation and reused.…”

Section: Resultsmentioning

confidence: 99%

“…The storage stability of BIND-PETase surpassed the PETase enzyme immobilized on magnetic iron oxide nanoparticles, which had 40%−70% loss of its enzyme activity during 2 week storage at 4 °C. 36 In addition, the whole-cell BIND-PETase biocatalyst could be recovered from the reaction solution by centrifugation and reused. The enzyme activity of BIND-PETase in pNPB hydrolysis retained 87.3% of the initial value after six repeated reaction cycles (Figure S8B).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Enzymatic Degradation of Polyethylene Terephthalate Plastics by Bacterial Curli Display PETase

Zhu

Seo

et al. 2022

Environ. Sci. Technol. Lett.

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The extensive production and use of polyethylene terephthalate (PET) have generated an enormous amount of plastic waste, which potentially threatens the environment and humans. Enzyme biocatalysis is a promising green chemistry alternative, relative to the conventional fossil-derived production process, to achieve plastic waste treatment and recycling. In this work, we created a biocatalyst, BIND-PETase, by genetically engineering the curli of an Escherichia coli cell with a functional PETase enzyme for biocatalytic degradation of PET plastics. BIND-PETase could degrade PET to generate degradation products at the concentration level of greater than 3000 μM under various reaction conditions. The effects of key reaction parameters, including pH, temperature, plastic substrate mass load, and surfactant addition were characterized. BIND-PETase was reusable for PET degradation and remained stable with no significant enzyme activity loss when stored at both 4 °C and room temperature for 30 days (Student’s t test, p > 0.05). Notably, BIND-PETase could enable the degradation of PET microplastics in wastewater effluent matrix. Moreover, BIND-PETase could depolymerize highly crystalline postconsumer PET waste materials under ambient conditions with degradation efficiency of 9.1% in 7 days. This study provides a new horizon for developing environmentally friendly biocatalytic approaches to solve the plastic degradation and recycling challenge.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Enzymatic Degradation of Polyethylene Terephthalate Plastics by Bacterial Curli Display PETase

Zhu

Seo

et al. 2022

Environ. Sci. Technol. Lett.

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“…62,71−76 Several published studies have explored PETase immobilization on metallic supports as a means of increasing stability by genetically fusing the enzyme to a metal-binding polyhistidine tag. 77,78 It has been shown that immobilization, even without introduction of spacer molecules to reduce steric hindrance, has the potential to enhance PETase activity and stability in harsh temperature and pH conditions 77,78 but the full scope of PETase immobilization has yet to be explored. Indeed, the majority of research on engineering PETase stability has focused on amino acid-level redesign of the free enzyme.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Chromatographic product detection would have the additional benefit of enabling direct comparison between the presented data and previously published PETase engineering research. While we are not able to contextualize the data sets discussed in this paper in the broader literature context due to the differences in methodologies employed, the general trend of improved stability upon immobilization without detectable loss in activity holds true across other studies 77,78 To further challenge the chemical stability of the enzyme, free PETase−SBP and PETase−SBP•Si were incubated for 6 days at 40 °C in synthetic influent (Figure 5). In these conditions, both free PETase−SBP and PETase−SBP•Si retained activity for 72 h (Figure 5b).…”

Section: ■ Introductionmentioning

confidence: 99%

“…Immobilization of enzymes on solid surfaces has numerous advantages in industrial contexts, including reusability and enhanced catalytic stability. ,,,,− Strategies for preparation of immobilized enzymes (covalent tethering through both native and installed functional groups, carrier-free cross-linking, both specific and nonspecific adsorption, etc.) have been reviewed in-depth by several research groups. ,− Several published studies have explored PETase immobilization on metallic supports as a means of increasing stability by genetically fusing the enzyme to a metal-binding polyhistidine tag. , It has been shown that immobilization, even without introduction of spacer molecules to reduce steric hindrance, has the potential to enhance PETase activity and stability in harsh temperature and pH conditions , but the full scope of PETase immobilization has yet to be explored. Indeed, the majority of research on engineering PETase stability has focused on amino acid-level redesign of the free enzyme. ,,,,− In this study, we address this gap in the literature by engineering both wild-type PETase and top PETase variants from the literature to self-immobilize on mesoporous silica nanoparticles for performance in the influent and effluent handling unit operations of the wastewater processing system.…”

Section: Introductionmentioning

confidence: 99%

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Directed Immobilization of PETase on Mesoporous Silica Enables Sustained Depolymerase Activity in Synthetic Wastewater Conditions

Zurier

Goddard

2022

ACS Appl. Bio Mater.

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Microplastic accumulation in terrestrial and aquatic environments is a growing environmental challenge. Biodegradation has shown promise as an intervention strategy for reducing the spread of microplastics. The wastewater treatment system is a key intervention point in microplastic biodegradation due to its pivotal role in the water cycle at the interface between human activity and the environmental. However, the best characterized microplastic degradation enzyme, PETase, lacks the stability to perform at scale in wastewater treatment. In this work, we show that genetic fusion of PETase to a silica binding peptide enables directed immobilization of the enzyme onto silica nanoparticles. PETase activity in simulated wastewater conditions is quantified by linear regression from time zero to the time of maximum fluorescence of a fluorescent oxidized product of PETase degradation of PET microfibers. Mesoporous silica is shown to be a superior support material to nonporous silica. The resulting biocatalytic nanomaterial has up to 2.5-fold enhanced stability and 6.2-fold increased activity compared to free enzyme in unbuffered, 40 °C simulated influent (ionic strength ∼15 mM). In unbuffered, 40 °C simulated effluent (ionic strength ∼700 μM), reaction velocity and overall catalytic activity were increased by the biocatalytic material 2.1-fold relative to free PETase. All reactions were performed in 0.2 mL volumes, and enzyme concentrations were normalized across both free and immobilized samples to 9 μg/mL. Site-directed mutagenesis is shown to be a complementary technique to directed immobilization, which may aid in optimization of the biomaterial for wastewater applications. PETase stabilization in application-relevant environments as shown here enables progress toward application of PETase for microplastic biodegradation in wastewater treatment.

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Metal Oxides‐Based Nano/Microstructures for Photodegradation of Microplastics

Kumar¹

2023

Advanced Sustainable Systems

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The ubiquitous presence of microplastics in the environment has raised serious environmental and health concerns. These tiny plastic particles can enter the food chain, posing a significant threat to human health. Researchers worldwide have focused their efforts on developing strategies to mitigate microplastic pollution. This review focuses on the potential of nano/microstructured metal oxide semiconductors as effective photocatalysts for microplastic degradation. The review is divided into two sections: static metal oxides and dynamic micromachines based on metal oxides. The modifications made to nano/microstructured metal oxides such as TiO2, ZnO, bismuth oxyhalides (BiOX), NiO, Cu2O/CuO, perovskite‐like Bi2WO6, Fe3O4, etc., to enhance their degradation efficiency are thoroughly discussed and reviewed. Additionally, the photocatalytic pathways for the conversion of microplastics into C2 fuel and other value‐added products are also elaborated. The current developments in the realm of dynamic, self‐propelled, and controlled micromotors for the photodegradation of microplastics are also highlighted. The review concludes by proposing future perspectives and challenges to facilitate the remediation of microplastics in water and wastewater systems in a more effective, scalable, and environmentally friendly manner. Overall, the review emphasizes the potential of photocatalysis using nano/microstructured metal oxide semiconductors as an eco‐friendly and promising approach for microplastic degradation.

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Immobilization of PETase enzymes on magnetic iron oxide nanoparticles for the decomposition of microplastic PET

Abstract: Polyethylene terephthalate (PET) is responsible for a large part of environmental contamination with microplastics. Based on the high affinity, the PET degrading enzyme PETase can be immobilized on superparamagnetic iron...

Cited by 52 publications

References 56 publications

Enzymatic Degradation of Polyethylene Terephthalate Plastics by Bacterial Curli Display PETase

Enzymatic Degradation of Polyethylene Terephthalate Plastics by Bacterial Curli Display PETase

Directed Immobilization of PETase on Mesoporous Silica Enables Sustained Depolymerase Activity in Synthetic Wastewater Conditions

Metal Oxides‐Based Nano/Microstructures for Photodegradation of Microplastics

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