Laccase Transformation of Antibiotics: Studying Breakdown and Algae Toxicity

Jenn Hoskins
14th August, 2024

Laccase Transformation of Antibiotics: Studying Breakdown and Algae Toxicity

Image Source: Natural Science News, 2024

Key Findings

  • The study by The Energy and Resources Institute and Deakin University explores using laccase enzymes from fungi to degrade fluoroquinolone antibiotics in water bodies
  • Fungi-derived laccase enzymes showed high degradation efficiency for antibiotics, with P. sajor caju achieving up to 78% degradation in vitro
  • Degradation products significantly reduced algal toxicity, suggesting a potential to mitigate ecological impacts of pharmaceutical contaminants
Pharmaceutical waste in water bodies poses significant environmental hazards. A recent study conducted by The Energy and Resources Institute and Deakin University explores a novel approach to degrade fluoroquinolone antibiotics (FQs) using laccase enzymes derived from three species of fungi: Pleurotus florida, Pleurotus eryngii, and Pleurotus sajor caju[1]. This study is pivotal in addressing the contamination of aquatic ecosystems by pharmaceuticals, a growing concern worldwide. The study investigates the ability of crude laccase extracts from the mentioned fungi to degrade five specific FQs: levofloxacin (LEV), norfloxacin (NOR), ciprofloxacin (CIP), ofloxacin (OFL), and enrofloxacin (ENR). These antibiotics are commonly found in water bodies due to improper waste disposal and inadequate wastewater treatment. The researchers compared the degradation efficiency of the fungi-derived laccase with commercially sourced laccase. Proteomics analysis confirmed the presence of laccase enzymes in all three fungal species, with protein profiles similar to those found in Trametes versicolor and Pleurotus ostreatus. In vivo experiments using pure fungal cultures showed that P. sajor caju achieved the highest degradation efficiency of 77.7% for LEV after 25 days of treatment. The degradation efficiencies for the other fungi ranged from approximately 60-72% for P. florida, 45-76% for P. eryngii, and 47-78% for P. sajor caju. In vitro experiments using crude extracts demonstrated even higher degradation efficiencies, with commercial laccase achieving 91-98%, P. florida 77-92%, P. eryngii 76-92%, and P. sajor caju 78-88%. The study utilized liquid chromatography-high-resolution mass spectrometry (LC-MS/MS) to identify the degradation products, revealing a consistent enzymatic pathway targeting the piperazine moiety common to all tested FQs. This finding is crucial as it indicates a uniform degradation mechanism, irrespective of the initial antibiotic structure. To assess the impact of the degradation products on ecosystems, phytoplankton toxicity studies were conducted using Dunaliella tertiolecta. The results showed a significant reduction in algal toxicity, with P. eryngii extracts achieving a 97.7% decrease for CIP and a 90% decrease for LEV. These outcomes suggest that laccase-mediated enzymatic oxidation can effectively reduce the ecological impact of pharmaceutical contaminants. This study builds on earlier findings that highlight the increasing prevalence of harmful algal blooms in lakes worldwide due to pollution[2]. The presence of low-dose contaminants has been shown to enhance the formation of harmful algal colonies and increase the production of toxins, making the control of algal blooms more challenging. The current study's findings suggest that laccase enzymes could play a role in mitigating these blooms by degrading pharmaceutical contaminants that contribute to the problem. Furthermore, previous research has demonstrated the effectiveness of laccase-catalyzed degradation of a broad spectrum of trace organic contaminants (TrOCs)[3][4]. The current study expands on this by focusing specifically on fluoroquinolone antibiotics and using naturally sourced laccase extracts, which could offer a more sustainable and environmentally friendly solution compared to commercial laccase. In conclusion, the study by The Energy and Resources Institute and Deakin University demonstrates the potential of using laccase enzymes from fungi to degrade fluoroquinolone antibiotics in water bodies. This approach not only addresses the issue of pharmaceutical contamination but also offers a promising solution to reduce the ecological impact of these contaminants. By leveraging naturally sourced enzymes, this method could provide a sustainable and effective means of mitigating pollution in aquatic ecosystems.

MedicineEnvironmentBiochem

References

Main Study

1) LACCASE MEDIATED TRANSFORMATION OF FLUOROQUINOLONE ANTIBIOTICS: ANALYZING DEGRADATION PATHWAYS AND ASSESSING ALGAL TOXICITY.

Published 11th August, 2024

https://doi.org/10.1016/j.envpol.2024.124700

Related Studies

2) Low Levels of Contaminants Stimulate Harmful Algal Organisms and Enrich Their Toxins.

https://doi.org/10.1021/acs.est.2c02763

3) Biocatalytic degradation of pharmaceuticals, personal care products, industrial chemicals, steroid hormones and pesticides in a membrane distillation-enzymatic bioreactor.

https://doi.org/10.1016/j.biortech.2017.09.129

4) Emergent contaminants: Endocrine disruptors and their laccase-assisted degradation - A review.

https://doi.org/10.1016/j.scitotenv.2017.09.013


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