Exposure to polystyrene nanoplastics reduces bacterial and fungal biomass in microfabricated soil models

Summary, in English

Nanoplastics have been proven to induce toxicity in diverse organisms, yet their effect on soil microbes like bacteria and fungi remains largely unexplored. In this paper, we used micro-engineered soil models to investigate the effect of polystyrene (PS) nanospheres on Pseudomonas putida and Coprinopsis cinerea. Specifically, we explored the effects of increasing concentrations of 60 nm carboxylated bovine serum albumin (BSA) coated nanospheres (0, 0.5, 2, and 10 mg/L) on these bacterial and fungal model organisms respectively, over time. We found that both microorganisms could disperse through the PS solution, but long-distance dispersal was reduced by high concentrations. Microbial biomass decreased in all treatments, in which bacteria showed a linear dose response with the strongest effect at 10 mg/L concentration, and fungi showed a non-linear response with the strongest effect at 2 mg/L concentration. At the highest nanoplastics concentration, the first colonizing fungal hyphae adsorbed most of the PS nanospheres present in their vicinity, in a process that we termed the 'vacuum cleaner effect'. As a result, the toxicity effect of the original treatment on subsequently growing fungal hyphae was reduced to a growth level indistinguishable from the control. We did not find evidence that nanoplastics are able to penetrate bacterial nor fungal cell walls. Overall, our findings provide evidence that nanoplastics can cause a direct negative effect on soil microbes and highlight the need for further studies that can explain how the microbial stress response might affect soil functions.

• Author: Paola M Mafla-Endara; Viktoriia Meklesh; Jason P Beech; Pelle Ohlsson; Milda Pucetaite; Edith C Hammer
• Department/s: Centre for Environmental and Climate Science (CEC); LU Profile Area: Light and Materials; LTH Profile Area: Nanoscience and Semiconductor Technology; LTH Profile Area: Engineering Health; Solid State Physics; NanoLund: Centre for Nanoscience; Acoustofluidics group; Department of Biomedical Engineering; Microbial Ecology; MEMEG; BECC: Biodiversity and Ecosystem services in a Changing Climate; LU Profile Area: Nature-based future solutions
• Publishing year: 2023-12-15
• Language: English
• Publication/Series: Science of the Total Environment
• Volume: 904
• Links: http://dx.doi.org/10.1016/j.scitotenv.2023.166503
• Document type: Journal article
• Publisher: Elsevier
• Topic: Microbiology; Environmental Sciences; Soil Science
• Status: Published
• Research group: Acoustofluidics group; Microbial Ecology
• ISBN/ISSN/Other: ISSN: 1879-1026