Cladosporium species detoxify multiple water micropollutants of emerging concern

Abstract

The accumulation of micropollutants of emerging concern in aqueous ecological niches raises safety concerns regarding biological systems and human health. Mycoremediation is a promising and green strategy to mitigate the micropollutant challenge. Hitherto, micropollutant transformation by white-rot Basidiomycota species has received most attention, whereas the potential of ascomycetes with respect to removal of micropollutants remains underexplored. Here, we assayed 53 Ascomycota isolates from 10 genera for the removal of 22 micropollutants, spanning large chemical diversity including mono- and multi-aromatic rings as well as different polarities, charge and halogen substitution. Functionally, the micropollutants included analgesic, antibiotics, antidepressant, anti-inflammatory, blood pressure regulating, and lipid-lowering drugs as well as anticorrosion agents, a herbicide, and an X-ray contrast agent. Notably, 9 out of the 22 micropollutants were removed from fungal culture supernatant at efficiencies > 45 %. Temporal analysis of the nine top-performing strains, highlighted a remarkable potency of the Cladosporium isolates in removal of multiple micropollutants. Importantly, Cladosporium species considerably reduced the toxicity of a cocktail of six micropollutants, based on growth assays. Metabolite network analyses identified different levels of oxidation and methylation biotransformation products for distinct micropollutants, whereas no products could be identified for other micropollutants, such as ciprofloxacin, sulfamethoxazole, and sertraline, hinting more extensive transformations. Genome sequencing and proteomic analyses were consistent with the observed transformations and tentatively identified the molecular apparatus, conferring micropollutant transformation. This study brings novel insight into the micropollutant transformation and detoxification capabilities of ecologically prevalent Cladosporium species, thereby revealing a considerable, albeit hitherto underappreciated potential of ascomycetes in micropollutant transformation.