Deoxynivalenol (DON) is frequently detected in cereals and cereal-based products and has a negative impact on human and animal health. In this study, an unprecedented DON-degrading bacterial isolate D3_3 was isolated from a sample of Tenebrio molitor larva feces. A 16S rRNA-based phylogenetic analysis and genome-based average nucleotide identity comparison clearly revealed that strain D3_3 belonged to the species Ketogulonicigenium vulgare. This isolate D3_3 could efficiently degrade 50 mg/L of DON under a broad range of conditions, such as pHs of 7.0–9.0 and temperatures of 18–30 °C, as well as during aerobic or anaerobic cultivation. 3-keto-DON was identified as the sole and finished DON metabolite using mass spectrometry. In vitro toxicity tests revealed that 3-keto-DON had lower cytotoxicity to human gastric epithelial cells and higher phytotoxicity to Lemna minor than its parent mycotoxin DON. Additionally, four genes encoding pyrroloquinoline quinone (PQQ)-dependent alcohol dehydrogenases in the genome of isolate D3_3 were identified as being responsible for the DON oxidation reaction. Overall, as a highly potent DON-degrading microbe, a member of the genus Ketogulonicigenium is reported for the first time in this study. The discovery of this DON-degrading isolate D3_3 and its four dehydrogenases will allow microbial strains and enzyme resources to become available for the future development of DON-detoxifying agents for food and animal feed.

In this study, a dual-member bacterial consortium with the ability to oxidize deoxynivalenol (DON) to 3-keto-DON, designated SD, was first screened from the feces of Tenebrio molitor larvae. This consortium consisted of Pseudomonas sp. SD17-1 and Devosia sp. SD17-2, as determined by 16S rRNA-based phylogenetic analysis. A temperature of 30 °C, a pH of 8.0–9.0, and an initial inoculum concentration ratio of Devosia to Pseudomonas of 0.1 were optimal single-factor parameters for the DON oxidation activity of the bacterial consortium SD. Genome-based bioinformatics analysis revealed the presence of an intact PQQ biosynthesis operon (pqqFABCDEG) and four putative pyrroloquinoline quinone (PQQ)-dependent alcohol dehydrogenase (ADH) genes in the genomes of Pseudomonas strain SD17-1 and Devosia strain SD17-2, respectively. Biochemical analyses further confirmed the PQQ-producing phenotype of Pseudomonas and the DON-oxidizing enzymatic activities of two of four PQQ-dependent ADHs in Devosia. The addition of PQQ-containing a cell-free fermentation supernatant from Pseudomonas activated DON-oxidizing activity of Devosia. In summary, as members of the bacterial consortium SD, Pseudomonas and Devosia play indispensable and complementary roles in SD’s oxidation of DON. Specifically, Pseudomonas is responsible for producing the necessary PQQ cofactor, whereas Devosia expresses the PQQ-dependent DON dehydrogenase, together facilitating the oxidation of DON.

We developed an alkaline phosphatase (AP) chemiluminescence immunoassay method by combining the superparamagnetic magnetic beads and the biotin–streptavidin signal amplification system to detect the triazolone and tebuconazole in wheat. Through optimization of the extraction solution and extraction time, acetonitrile–PBS was selected as the extraction solution with an extraction time of 5 min as the optimal pretreatment condition. Optimizing the dilution ratio of antigen antibodies, the optimal detection conditions were selected as the dilution ratios of 1:8000 and 1:20,000 for the triazolone monoclonal antibody solution and biotinylated triazolone solution, and 1:4000 and 1:20,000 for the tebuconazole monoclonal antibody solution and biotinylated tebuconazole solution, respectively. Under the optimal conditions, the method demonstrated that the limits of detection (LOD) of triazolone and tebuconazole were 0.002835 μg·mL⁻¹ and 0.00064 μg·mL⁻¹, respectively. The recovery rate was between 90.1% and 103.6%, and the relative standard deviation (RSD) was lower than 10%. The cross-reaction rates for structural analogs were all less than 0.1%, showing good specificity. In actual sample detection, this method did not detect triazolone and tebuconazole, and the results were consistent with UHPLC-MS/MS.