Evolutionarily conserved mucus-mediated nanoplastic bioflocculation in Tetrahymena

Area of Science:

• Environmental Science
• Microbiology
• Ecotoxicology

Background:

• Nanoplastics (NPs) are persistent environmental pollutants posing significant remediation challenges.
• Conventional methods for NP removal are often inefficient, highlighting the need for novel solutions.
• Understanding biological interactions is crucial for accurate NP fate modeling.

Purpose of the Study:

• To investigate the role of protozoa in nanoplastic remediation.
• To elucidate the mechanism by which Tetrahymena sequesters nanoplastics.
• To assess the impact of protozoan bioflocculation on NP environmental fate.

Main Methods:

• Exposure of Tetrahymena to nanoplastics.
• Induction and observation of mucus secretion.
• Quantification of NP reduction in aqueous solutions.
• Multi-omics analyses (genomics, transcriptomics, proteomics) to identify involved pathways.
• Assessment of NP aggregation and sedimentation.

Main Results:

• Tetrahymena activates a Ca2+-dependent mucus secretion upon NP exposure.
• This process leads to nano-scale aggregation, reducing aqueous NP concentrations by 41.6%-44.8%.
• Bioflocculation enriches NPs in sedimentary sinks, mitigating atmospheric dispersion.
• Multi-omics identified Ca2+-mediated GRL secretion dynamics linked to bioflocculation.

Conclusions:

• Protozoan bioflocculation offers an effective pathway for nanoplastic remediation.
• This biological process fundamentally alters NP environmental fate, reducing risks.
• Findings necessitate revisions to NP fate models and global risk assessment frameworks.
• Protozoa play a critical, underappreciated role in mitigating NP pollution.