Isolation and Identification of Aflatoxin B₁ Degradation Strains

Objective:The aim of this research was to isolate aflatoxin B₁ (AFB₁) -degrading strains from different habitats which easily contaminated by aflatoxin B₁.Methods:Using cumarin as the carbon source and energy to have the first screening. The strains that could grow in the medium with coumarin carbon source were detected for their degradation of AFB₁ ability by addition of AFB₁ (2.5 μg/mL). Among the grow well strains which had the highest degradation rate was preliminarily identified according to its morphological and analysis of its 16S rDNA sequence. Degradation of AFB₁ by cell-free supernatant, strain cells, and intracellular cell extracts of strain. Results:Strain XY1, obtained from decay deadwood (poplar) could reduce AFB₁ by 71.91% after incubation. XY1 was preliminary identified to be Klebsiella sp. with morphology and 16S rDNA gene sequence The cell-free supernatant (70.23%) of isolate XY1 was able to degrade AFB₁ effectively, whereas the viable cells (8.26%) and cell extracts (3.18%) were far less effective. Conclusion:An AFB₁-degrading strain XY1 was isolated from decay deadwood (poplar) and identified as Klebsiella sp.. The activive component of AFB₁ degradation was mainly in the cell-free supernatant of XY1.