Isolation, Identification and Application of Bacillus subtilis Degrading Deoxynivalenol

Deoxynivalenol (DON) is one of the most harmful mycotoxins in cereals and their products, which is a serious threat to food and feed safety. Traditional physical and chemical methods have problems such as low efficiency or secondary pollution, so it is urgent to develop efficient and safe detoxification strategies. In this study, based on the diversity of microbial resources, DON was used as the only carbon source to screen efficient degrading strains from soil samples, and the strains were identified through morphological observation and 16S rDNA phylogenetic analysis, and the cell-free supernatant enzyme activity experiment and solid state fermentation process optimization were used to explore their degradation characteristics. The results showed that a strain of Bacillus subtilis 1-E-8 was obtained, which entered the stable growth stage at 14 h, and the degradation rate of DON reached 87.81% at 16 h. The degradation rate of the cell-free supernatant reached 86.60% in 24 h, which proved that the degradation process was mediated by extracellular protease. After optimizing the solid state fermentation conditions (48 h, 37℃, 2% inoculated amount, solid-liquid ratio 1:1 g/mL), the degradation rate of DON exceeded the standard wheat flour reached 72.40%, and the number of viable bacteria reached the peak at 48 h (4.9×10⁹ CFU/g), which was positively correlated with the degradation efficiency. This study revealed the DON degradation characteristics of Bacillus subtilis 1-E-8 and the action mode of extracellular enzymes, established an efficient degradation process, and provided a theoretical basis for the development of biological demildew agents.