Isolation, identification and application of Bacillus subtilis for degrading deoxynivalenol

Deoxynivalenol (DON) exhibits high toxicity in cereals and their products, posing a serious threat to food and feed safety. Traditional physical and chemical detoxification methods suffer from issues such as low efficiency or secondary pollution, making it urgent to develop efficient and safe detoxification strategies. In this study, based on the diversity of microbial resources, DON was used as the sole carbon source to screen for high-efficiency degrading strains from soil samples. The isolated strains were identified via morphological observation and 16S rDNA phylogenetic analysis, while the degradation characteristics of the target strain were investigated through cell-free supernatant enzyme activity assays and optimization of solid-state fermentation processes. The results showed that one strain, designated as Bacillus subtilis 1-E-8, entered the stationary growth phaes at 14 h, with a DON degradation rate of 87.81% at 16 h. The cell-free supernatant achieved a DON degradation rate of 86.60% within 24 h, confirming that the degradation process is mediated by extracellular protease. After optimizing the solid-state fermentation conditions (fermentation time: 48 h, temperature: 37 ℃, inoculum size: 2%, solid-to-liquid ratio 1∶1 g/mL), the degradation rate of DON in wheat flour with excessive DON reached 72.40%. Additionally, the viable cell count peaked at 48 h (4.9×10⁹ CFU/g), which was positively correlated with the degradation efficiency. This study clarifies the DON degradation characteristics of Bacillus subtilis 1-E-8 and the mechanism of action of its extracellular enzymes, establishes an efficient degradation process, and provides a theoretical basis for the development of biological mycotoxin detoxifiers.