Fungi of plastisphere: a possible bioresources for bioremediation purpouses

Plastic pollution is an environmental issue in both aquatic and terrestrial ecosystems. In 2013, the term “plastisphere” was coined to refer to this new human-made ecosystem where plastic debris provides a substrate that can be colonized by microorganisms through the formation of a biofilms. The study of microbial biodiversity of the plastisphere and its metabolome is therefore fundamental for the development of several biotechnological applications. Nowadays, several microorganisms are known to be promising plastic degraders, fungi included. This work aims to analyze the mycobiota associated with plastic wastes using a culturomic approach. Sediments samples of three marine sites, with different anthropic impacts, were performed in the Tirrenian Sea in Tuscany. Studies are ongoing: hundreds of strains were isolated from microplastics and/or sediments. As regard terrestrial ecosystems, several fungi were isolated from a plastic-polluted landfill soil and their degradation abilities against conventional and biodegradable polymers were explored. Some strains have already been characterized for the capability to attach persistent (polyethylene) and biodegradable (polybutylene succinate) plastics. This unexplored microbial biodiversity useful for bioremediation activities will be useful to face the emerging environmental problem of the spread of plastic in all environments,. Moreover, the enzymatic pathways involved in the degradation processes are under study since it would be useful to build up innovative enzymatic treatments to allow a plastic circular economy. Indeed, expanding the knowledge on plastisphere microorganisms and on their bioremediation capability would help to design new biodegradable plastics by selecting new macromolecules with the desired “plastic” features accessible for microbial degradation.