CE04 - Innovations scientifiques et technologiques pour accompagner la transition écologique

Fungal communities associated with marine plastic waste and their bioremediation potential – MycoPLAST

Fungal communities associated with marine plastic waste and their bioremediation potential

Plastics debris pervades in our oceans and freshwater systems at an increasing accumulation rate. While identifying the major sources of plastics are critical, greater investigations on the plastic microbiome to characterize the whole microbial communities appear also essential. The major aim of MycoPLAST is thus to highlight specific microbial communities, and more precisely fungal communities, able to degrade plastics.

Merging microbial ecology approaches to better understand the colonization and degradation potential of marine fungal communities

In recent years, evidence has accumulated for the presence and activity of fungal communities in a wide variety of aquatic habitats. While numerous studies have provided evidence for metabolically active marine fungi, the extent to which they make a significant contribution to biogeochemical cycling of compounds, including pollutants, is still unknown. The overall aims of this proposal are to assess the diversity, activity and distribution of fungi associated with marine plastic debris samples and to evaluate, and possibly unleash, their ability to degrade complex plastic polymers.

Objectives will be achieved (i) by providing detailed information on the identity and environmental significance of fungi associated to a wide variety of plastic samples (retrieved from different aquatic habitats) using molecular marker gene analyses, (ii) by establishing an extensive collection of fungal isolates and by determining their ability to efficiently degrade plastic polymers, and (iii) by optimizing the utilization/degradation yield through microbial consortia, use of surfactants and constrained adaptation through iterative culturing.

WP1 (Sample collection and processing). Aim of this WP was to generate an exhaustive collection of plastic waste samples from a variety of environments. In addition to the samples collected during the “Tara Microplastics 2019” oceanographic campaign (https://oceans.taraexpeditions.org/m/science/les-actualites/cp-mission-microplastics-2019/) which are currently being analyzed, many plastic samples from marine immersion experiments were obtained: (i) PVC (PolyVinyl Chloride) submerged in the bay of Toulon, Banyuls-sur-Mer, Lorient and La Réunion, in collaboration with the University of Toulon (ii) PE (PolyEthylène) and PP (PolyPropylene) submerged in the harbor of Brest, in collaboration with the European University Institute of the Sea, (iii) PS (PolyStyrène) submerged in the Marina of the port of Brest, in collaboration with Cèdre (The Centre of Documentation,Research and Experimentation on Accidental Water Pollution) and (iv) PE, PCL (PolyCaproLactone) and PHBV (PolyHydroxyButyrateValerate) immersed in the port of Banyuls, in collaboration with the Banyuls-sur-Mer Oceanological Observatory. To date, nearly 270 samples have been collected. The results generated from these projects will be compared with each other but also with the data present in various previous studies (Kettner et al. 2017, Lacerda et al. 2020) in order to process a meta-analysis and to confirm our conclusions.


WP2 (Illumina iTag profiling of fungal and bacterial communities). This WP aimed to characterize microbial diversity by a metabarcoding approach via the sequencing of genetic markers (18S, ITS and 16S). With the exception of the PS samples immersed in the Marina of the port of Brest (experiment carried out in July-August 2021), DNA extractions, amplification and sequencing of genetic markers were carried out. The microbial ecology analyzes allowed to highlight the first trends, namely (i) a more complex fungal diversity on the seawater samples compared to the plastic samples, suggesting a form of selection of fungal communities on plastic samples and therefore extend to fungi the concept of Plastisphere, widely demonstrated for bacteria and (ii) a specificity of fungal communities depending on the type of polymer, suggesting a different colonization potential depending on the type of plastic polymer.


WP3 (Isolation and identification of fungi and bacteria using high-throughput culturing). This WP aims to generate a representative collection of fungal isolates from plastic waste samples. By approaches coupling high-throughput culturing and conventional approaches, a collection of 250 fungal isolates has been established to date (knowing that only half of the collection of plastics has been analyzed to date, by cultural approach). These 250 isolates, now purified and preserved in our collection, will subsequently be identified and screened for their degradation capacity (WP4).

WP4 (Test of biodegradation abilities). This WP aimed at highlighting the degradation capabilities of our fungal isolates has not yet been initiated yet. Nevertheless, the cultural approach implemented within the framework of WP3 (culture media enriched with polymers) has already shown signs of degradation.

Book chapter:

Burgaud G, Edgcomb VP, Hassett BT, Li W, Mara P, Philippe A, et al. Marine Fungi. In : The Marine Microbiome vol.2 (Springer, 2021). In press

Dissemination activities:

European Researchers' Night, September 2021 (Brest). « 0 plastics journey ». (Burgaud G et Philippe A)

Scientific seminar organized by Institute Mines-Telecom students. Talk dealing with the Tara Microplastics 2019 oceanographic cruise and more specifically on the plastic waste topic. Burgaud G. January 2020 (Brest).

Plastics debris pervades in our oceans and freshwater systems at an increasing accumulation rate. While identifying the major sources of plastics are critical, greater investigations on the plastic microbiome to characterize the whole microbial communities and putative plastic-degraders appear also essential. The major aim of MycoPLAST is thus to address the problematic of the fate of marine plastic litter which appears particularly relevant to the CES 04 “Scientific and technological innovations to support the ecological transition” as we will highlight specific microbial communities able to degrade plastics. The MycoPLAST proposal fits well with the CES associated keywords “bioremediation”, “ecological engineering”, “pollutant treatment”, “treatment of waste” and “pollution of waters”.

In recent years, evidence has accumulated for the presence and activity of fungal communities in a wide variety of aquatic habitats. While numerous studies have provided evidence for metabolically active marine fungi, the extent to which they make a significant contribution to biogeochemical cycling of compounds, including pollutants, is still unknown. The overall aims of this proposal are to assess the diversity, activity and distribution of fungi associated with marine plastic debris samples and to evaluate, and possibly unleash, their ability to degrade complex plastic polymers. This will be achieved (i) by providing detailed information on the identity and environmental significance of fungi associated to a wide variety of plastic samples (retrieved from different aquatic habitats) using molecular marker gene analyses, (ii) by establishing an extensive collection of fungal isolates and by determining their ability to efficiently degrade plastic polymers, and (iii) by optimizing the utilization/degradation yield through microbial consortia, use of surfactants and constrained adaptation through iterative culturing.

Our main hypothesis is that marine fungal communities represent an overlooked and untapped microbial component associated with marine plastic waste and that a better knowledge of their diversity, activity, functions and the exploration of their potential ability to degrade complex plastics could lead to efficient bioremediation applications in the current context of global threat to the planet and its inhabitants.

Noteworthy, in addition to the access to a large collection of plastic samples from different marine locations, the proposed project will take advantage of a funded Tara Expedition starting in May 2019 for a “Tour of Europe”. During this expedition, having for theme ocean research and the preservation of the Ocean in the face of plastic pollution, “fresh” plastic samples (meso, micro and nanoplastics) will be collected and will also be accessible to the MycoPLAST project.

The limited but nevertheless encouraging studies on these specific microorganisms clearly highlight the interest of this research topic, allowing to consider that the MycoPLAST project is highly original and will definitely lead to scientific breakthroughs and can be a first step towards standardized bioremediation approaches lowering plastic pollution in the Ocean through the bio-stimulation of specific marine microbial degraders.

Project coordinator

Monsieur Gaëtan Burgaud (LABORATOIRE UNIVERSITAIRE DE BIODIVERSITE ET ECOLOGIE MICROBIENNE)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

OUC Ocean University of China / Li's lab
Woods Hole Oceanographic Institution / Edgcomb's lab
ICCF INSTITUT DE CHIMIE DE CLERMONT-FERRAND
MAPIEM LABORATOIRE MATERIAUX POLYMERES INTERFACES - ENVIRONNEMENT MARIN
EA3882 LABORATOIRE UNIVERSITAIRE DE BIODIVERSITE ET ECOLOGIE MICROBIENNE

Help of the ANR 194,400 euros
Beginning and duration of the scientific project: January 2020 - 42 Months

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