Remediation in an agroecosystem : microbial detoxification of deoxynivalenol

Mycotoxins are secondary metabolites produced by fungi. When these fungi are present on agricultural commodities, they can pose a high risk to animal and human health. As the European Commission imposes strict regulations on maximum levels of several mycotoxins, it is a prerequisite for farmers to meet these regulations to avoid complete loss of a contaminated batch. In an agro-ecosystem, farmers try to avoid fungal infection and the occurrence of mycotoxins in their commodities via prevention and intervention approaches, but often fail in completely eliminating the risk. Therefore, detoxification strategies are needed such as the use of binders or microorganisms able to detoxify these mycotoxins. Our project focuses on the microbial detoxification of deoxynivalenol (DON), a worldwide prevalent mycotoxin. Bacteria were screened from natural environments for their DON-detoxification capacity in minimal medium through HPLC-UV and non-targeted LC-MS/MS. Furthermore, the residual toxicity was measured with a bioassay using the aquatic bio-indicator plant Lemna minor. Pursuing this approach, two mixed cultures were obtained, originating from soil and activated sludge, capable of converting DON into the epimer of DON and the epimer of DOM-1, both conveying no residual toxicity for the Lemna minor plant