Biodegradation of Aflatoxin B1 by Aspergillus niger and Transcriptome Analysis

Abstract:

Among the known mycotoxins, aflatoxin B₁ (AFB₁) is the most toxic, and its impact on food safety has caused widespread concern. To explore the degradation mechanism of AFB1 by Aspergillus niger FS10, different fractions of A.niger FS10(suspension, fermentation, spores, mycelium) were used to degrade AFB₁. The effects of AFB₁ stimulation on the degradation of A.niger FS10 were studied and the morphological changes of A.niger FS10 mycelium during the degradation process were observed under scanning electron microscope. Finally, the possible mechanism of AFB₁ degradation was explored by transcriptome technology. The results showed that AFB₁ could be effectively degraded by A.niger FS10, and the removal rate of AFB₁ was 98.65% after 72 h treatment. The spores of A.niger FS10 insignificantly affected the AFB₁ removal, but the mycelium had a certain adsorption capacity for AFB₁ and the fermentation broth had obvious effect on the removal of AFB1. After the induced stimulation of AFB₁, the degradation effect of A.niger FS10 was significantly improved, indicating that AFB₁ treatment could significantly improve the degradation ability of A.niger FS10 to AFB₁. The microstructure analysis showed that AFB₁ treatment affected the morphology of A.niger FS10 to a certain extent, but this effect gradually decreased with the treated time. Moreover, the transcriptomic analysis showed that AFB₁ treatment decreased the levels of some energy metabolism-related genes, which might be a self-protection mechanism of A.niger FS10. And the up-regulation of methionine synthesis genes suggested that the degradation of AFB1 might be related to the methionine synthesis process.