Cladosporium species detoxify multiple water micropollutants of emerging concern using diverse strategies

Abstract

The accumulation of micropollutants of emerging concern in aqueous systems raises safety concerns regarding biological systems and human health. Mycoremediation is a promising and green strategy to mitigate the micropollutant challenge. Hitherto, focus has mainly been on white-rot Basidiomycota and micropollutant transformation by ascomycetes remains underexplored. Here, we assayed 53 Ascomycota isolates from 10 genera for the removal of 22 micropollutants. Notably, 9 out of 22 micropollutants were removed from fungal culture supernatant at efficacies >45%. Temporal analysis of the nine top- performing strains, highlighted remarkable potency of Cladosporium isolates in removal of multiple micropollutants. Importantly, Cladosporium considerably reduced the toxicity of a micropollutant cocktail based on growth assays. Metabolomics analyses identified oxidation for 5-methyl-1H-benzotriazole and citalopram, whereas methylation and carboxylation were observed for 5-chlorobenzotriazole. No transformation products were detected for ciprofloxacin, sulfamethoxazole, and sertraline, hinting their extensive degradation. These findings suggest micropollutant transformation via diverse catalytic routes by Cladosporium. Genome sequencing and proteomic analyses of the top-performing isolates were consistent with the observed transformations and tentatively identified the molecular apparatus, conferring micropollutant transformation. This unprecedented study brings novel insight into the micropollutant transformation and detoxification capabilities of the prevalent Cladosporium species, thereby revealing a considerable and hitherto underappreciated potential of this genus and potentially other ascomycetes in micropollutant transformation. ImportanceAt present, conventional wastewater treatment plants (WWTPs) are not designed for removing micropollutants, which are released into aqueous systems. This raises concerns due to the poor insight into micropollutant long-term interplay with biological systems. Innovating biotechnological solutions to tackle micropollutant require addressing the paucity of knowledge on microbial groups and molecular pathways, which mediate micropollutant transformation. Our study highlights the considerable potential of the Cladosporium genus that remains underexplored in the arena of micropollutant transformation. We report the first genomes sequences for three Cladosporium species: C. allicinum, C. inversicolor, and C. fusiforme, which sets the stage for further analyses of micropollutant transformation, but also offers an important resource on this ecologically significant, albeit under-studied genus and related Ascomycota.