Deoxynivalenol Detoxification by a Novel Strain of Pichia kudriavzevii via Enzymatic Degradation and Cell Wall Adsorption.

Deoxynivalenol (DON) is a mycotoxin that significantly threatens the food and feed industry. Corn steep liquor (CSL) is an acidic byproduct of the corn starch industry, and DON is concentrated in CSL once the material is contaminated. In this work, a Pichia kudriavzevii strain that could remove DON from CSL was isolated and characterized. The strain P. kudriavzevii E4-205 showed detoxifying activity in a pH range of 4.0~7.0 and temperature of 25~42 °C, and 39.4% DON was reduced by incubating this strain in CSL supernatant diluted by 2-fold (5 μg/mL DON) for 48 h at pH 5.0 and 30 °C. Further mechanism studies showed that P. kudriavzevii E4-205 could adsorb DON by the cell wall and degrade DON by intracellular enzymes with NADH as a cofactor. The degradation product was identified as 3,7,8,15-tetrahydroxyscirpene by liquid chromatography-tandem mass spectrometry. DON adsorption by inactivated cells was characterized, and the adsorption followed pseudo first-order kinetics. This study revealed a novel mechanism by which microbes degrade DON and might serve as a guide for the development of DON biological detoxification methods.