P45: Isolation of a novel bacterial strain capable of detoxifying the mycotoxin deoxynivalenol

Cereals are frequently contaminated with the mycotoxin deoxynivalenol (DON, commonly known as ‘vomitoxin’), which is a serious health hazard to humans and animals upon consumption.  In order to identify a novel microbial source capable of transforming deoxynivalenol to a less toxic compound, 150 soil samples from different crop fields of Southern Ontario, Canada were analyzed for their ability to de-epoxidize DON to de-epoxy DON (dE-DON). The screen identified a bacterial strain that showed 100% biotransformation of DON to dE-DON in mineral salts broth supplemented with 0.5% Bacto™ Peptone after 60 h of incubation. The purified bacterial strain showed rapid DON transformation activity at neutral pH (7.0) and moderate temperatures (27-30°C) under both aerobic and anaerobic conditions. The bacterium is gram-negative, facultatively anaerobic, motile, rod-shaped (1.52 X 0.72 µm) and has several flagella. 16s-rRNA sequence analysis revealed that the bacterial strain belongs to the gamma subclass of proteobacteria. We believe that this is the first report of microbial DON to dE-DON biotransformation under aerobic/anaerobic conditions and moderate temperatures. The isolate could be used to detoxify DON contaminated feed. In addition, the occurence of DON contaminated food could be reduced by cloning the antitoxin gene and using it to stably transform cereals.