The Study Of Deoxynivalenol Degrading Bacteria And Degrading Enzymes

Deoxynivalenol (DON) is the most common grain contamination, which is produced by Fusarium. Fusarium and its produced mycotoxins cause great economic losses worldwide. The objective of this research is to degrade DON, reduce its hazards, safeguard quality and safety in creals&oils and food by using biotechnology. This research mainly contains three parts:screening and identificating DON degrading bacteria, speculating the structure of degradant product, degrading enzymes preliminary research, which is briefly outlined as follow:DON is regarded as the sole carbon source by plate separation and purification, detected by high performance liquid chromatography (HPLC). The strain with higher degradation is identified through molecular identification. The strain’s degradation rate for DON was56.61%. This strain is identified as Pseudomonas via16S rDNA sequencing. The selected strain shows a remarkable performance in DON degradation.We find that the degrading bacteria degradate DON for new degradation products, the fragment ions of which is m/z265.1345, may lose CH2O through Q-TOF mass spectrometry analysis. We can speculate the possible structure of the degradation products through structural analysis.The degrading enzyme treatment for Distillers Dried Grains (DDG) last3hours, then the degrading rate reach53.71%, when treatment last12hours, degrading rate reach88.66%. The degrading enzyme shows a remarkable performance in DON degradation in DDG. The degradation effect can be improved by emulsificating DDG. But the high shear forces generated by the enzyme emulsified can slightly affect enzyme activity. Under acidic conditions will seriously affect the enzyme activityDry DDGS after distilled alcohol exists DON residues. The degrading enzyme treatment for DDGS last12hours, then the Don residues can not be detected. The best Eukaryotic degrading enzyme degradation conditions at37℃, pH7by optimizing degrading enzyme degradation conditions.The results of the above studies supply a benefit gene source and technical support for exploring a new DON degradation gene, industrializing degrading enzymes, reducing DON contamination levels in grain, feed.