Abstract
Deoxynivalenol (DON) is a secondary metabolite produced by several Fusarium species that is hazardous to humans and animals after entering food chains. In this study, by adding cofactors, the Devosia strain A6-243 is identified as the DON-transforming bacteria from a bacterial consortium with the ability to biotransform DON of Pseudomonas sp. B6-24 and Devosia strain A6-243, and its effect on the biotransformation process of DON is studied. The Devosia strain A6-243 completely biotransformed 100 μg/mL of DON with the assistance of the exogenous addition of PQQ (pyrroloquinoline quinone) within 48 h and produced non-toxic 3-epi-DON (3-epi-deoxynivalenol), while Pseudomonas sp. B6-24 was not able to biotransform DON, but it had the ability to generate PQQ. Moreover, the Devosia strain A6-243 not only degraded DON, but also exhibited the ability to degrade 3-keto-DON (3-keto-deoxynivalenol) with the same product 3-epi-DON, indicating that DON epimerization by the Devosia strain A6-243 is a two-step enzymatic reaction. The most suitable conditions for the biodegradation process of the Devosia strain A6-243 were a temperature of 16–37 °C and pH 7.0–10, with 15–30 μM PQQ. In addition, the Devosia strain A6-243 was found to completely remove DON (6.7 μg/g) from DON-contaminated wheat. The results presented a reference for screening microorganisms with the ability of biotransform DON and laid a foundation for the development of enzymes for the detoxification of mycotoxins in grain and its products.
Highlights
Mycotoxins, including deoxynivalenol, trichothecenes, zearalenone, and aflatoxins, which are secondary metabolites that are mainly produced by Aspergillus, Penicillium, and Fusarium genera, are toxic to both humans and animals [1,2,3,4,5]
We isolated a bacterial consortium of Pseudomonas sp
In order to further analyze which bacteria played the main role in the DON biotransformation by Pseudomonas sp
Summary
Mycotoxins, including deoxynivalenol, trichothecenes, zearalenone, and aflatoxins, which are secondary metabolites that are mainly produced by Aspergillus, Penicillium, and Fusarium genera, are toxic to both humans and animals [1,2,3,4,5]. Several microorganisms with the ability to biotransform DON have been successfully isolated, including Aspergillus tubingensis, Nocardioides sp., and Devosia sp. Two enzymes called DepA and DepB were isolated from Devosia sp., which converted DON to 3-keto-DON and 3-keto-DON to 3-epi-DON, respectively [7]. This is the first time that research has proven that the complete isomerization process at the C3 position of DON is a two-part reaction involving two enzymes. For some mixed bacteria cultures, one kind of bacteria produces cofactors to support another kind of bacteria with the enzymes, together building up the ability to biotransform DON
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