Cations impact the biodegradation of iodosulfuron-methyl herbicidal ionic liquids by fungi

In the framework of this study, six fungal isolates which demonstrated a high capability for biodegrading iodosulphuron-methyl sodium as well as herbicidal ionic liquids based on this herbicide were isolated from different soil samples. The isolates were identified based on the ITS region, whereas biodegradation residues were determined based on LC-MS/MS. Depending on the isolate, the half-lives values of the biodegraded herbicide or herbicidal ionic liquid ranged significantly from just 1.25 days to more than 40 days. The research findings unveiled that the structure of cations is a central limiting factor affecting fungal growth and herbicide transformation in case of ionic liquids. The length of the alkyl chain has been identified as the primary driver of herbicide toxicity, emphasizing the importance of structural factors in herbicide design. In cases when dodecyl(2-hydroxyethyl)dimethyl cation was used, its biodegradation ranged from 0 to approx. 20% and the biodegradability of the iodosulfuron-methyl was notably limited for the majority of the studied isolates. This knowledge provides guidance for development and selection of herbicides with reduced environmental impact. This study highlights the ecological importance of soil fungi, their potential role in herbicide biodegradation, the influence of cations on fungal growth and herbicide transformation, and the structural factors governing herbicide toxicity. Further research in these areas may lead to more efficient and environmentally friendly approaches to herbicide management.