AFB1 Microbial Degradation by Bacillus subtilis WJ6 and Its Degradation Mechanism Exploration Based on the Comparative Transcriptomics Approach

Aflatoxin pollution poses great harm to human and animal health and causes huge economic losses. The biological detoxification method that utilizes microorganisms and their secreted enzymes to degrade aflatoxin has the advantages of strong specificity, high efficiency, and no pollution inflicted onto the environment. In this study,Bacillus subtilisWJ6 with a high efficiency in aflatoxin B1degradation was screened and identified through molecular identification, physiological, and biochemical methods. The fermentation broth, cell-free supernatant, and cell suspension degraded 81.57%, 73.27%, and 8.39% of AFB1, respectively. The comparative transcriptomics analysis indicated that AFB1led to 60 up-regulated genes and 31 down-regulated genes inB. subtilisWJ6. A gene ontology (GO) analysis showed that the function classifications of cell aggregation, the organizational aspect, and the structural molecule activity were all of large proportions among the up-regulated genes. The down-regulated gene expression was mainly related to the multi-organism process function under the fermentation condition. Therefore,B. subtilisWJ6 degraded AFB1through secreted extracellular enzymes with the up-regulated genes of structural molecule activity and down-regulated genes of multi-organism process function.Keywords:aflatoxin B1;Bacillus subtilis;microbial degradation;comparative transcriptomics;biological detoxification