The mycotoxin deoxynivalenol (DON), produced in wheat, barley and maize by Fusarium graminearum and Fusarium culmorum, is threatening the health of humans and animals. With its worldwide high incidence in food and feed, mitigation strategies are needed to detoxify DON, maintaining the nutritional value and palatability of decontaminated commodities. A promising technique is biological degradation, where microorganisms are used to biotransform mycotoxins into less toxic metabolites. In this study, bacterial enrichment cultures were screened for their DON detoxification potential, where DON and its potential derivatives were monitored. The residual phytotoxicity was determined through a bioassay using the aquatic plant Lemna minor L. Two bacterial enrichment cultures were found to biotransform DON into a still highly toxic metabolite for plants. Furthermore, a cytotoxic effect was observed on the cellular viability of intestinal porcine epithelial cells. Through liquid chromatography high-resolution mass spectrometry analysis, an unknown compound was detected, and tentatively characterized with a molecular weight of 30.0 Da (i.e., CH2O) higher than DON. Metabarcoding of the subsequently enriched bacterial communities revealed a shift towards the genera Sphingopyxis, Pseudoxanthomonas, Ochrobactrum and Pseudarthrobacter. This work describes the discovery of a novel bacterial DON-derived metabolite, toxic to plant and porcine cells.
Keywords: bioassay; biotransformation; cytotoxicity assay; deoxynivalenol derivatives; enrichment; metabarcoding.