Exploration of biodegradation mechanism by AFB1-degrading strain Aspergillus niger FS10 and its metabolic feedback

Exploration of biodegradation mechanism by AFB1-degrading strain Aspergillus niger FS10 and its metabolic feedback

Significant progress has been made in the biological degradation of aflatoxin B-1 (AFB(1)), which is the most toxic and carcinogenic mycotoxin commonly found in food and feed products; however, research in this area has currently focused on the effective methods for detoxifying AFB(1) and the mechanisms underlying the degradation process. The relationship between AFB(1) biotransformation and the metabolic feedback by the AFB(1)-degrading strain has rarely been reported. This study investigated the biotransformation pathway of AFB(1) in a highly efficient degrading strain, Aspergillus niger FS10, and the metabolic regulation of FS10 during AFB(1) degradation. We analyzed the AFB(1) metabolic degradation products and evaluated its toxicity based on its structures by triple quadrupole-linear ion trap-mass spectrometry (Q-Trap-MS) coupled with LightSight (TM) Software. Four metabolic degradation products were obtained: Product 1 (C17H14O6), Product 2 (C17H14O7), Product 3 (C16H12O5), and Product 4 (C27H31N3O13, AFB(2)-GOH). Two biotransformation pathways were proposed based on the structures of these degradation products. Metabolomics data revealed that FS10 exhibited different degrees of bioremediation under low-, mediumand highdose AFB(1). The results also suggested the significant involvement of glutathione, a metabolite, in the AFB(1) biotransformation pathway and its formation of AFB(2)-GOH with AFB(1). The four products could probably be less toxic than AFB(1), as reflected by changes in the AFB(1) toxicity site. Therefore, the AFB(1)-degrading strain FS10 exhibits great potential for application in the detoxification of AFB(1) in food and feed products.

黄曲霉毒素B - 1（AFB(1)）是食品和饲料产品中常见的毒性最强且致癌的霉菌毒素，其生物降解已取得重大进展；然而，该领域的研究目前集中在AFB(1)解毒的有效方法以及降解过程的潜在机制上。AFB(1)生物转化与AFB(1)降解菌株的代谢反馈之间的关系鲜有报道。本研究探讨了高效降解菌株黑曲霉FS10中AFB(1)的生物转化途径以及FS10在AFB(1)降解过程中的代谢调控。我们通过三重四极杆 - 线性离子阱 - 质谱（Q - Trap - MS）结合LightSight（TM）软件，分析了AFB(1)代谢降解产物，并根据其结构评估了毒性。得到了四种代谢降解产物：产物1（C17H14O6）、产物2（C17H14O7）、产物3（C16H12O5）和产物4（C27H31N3O13，AFB(2) - GOH）。基于这些降解产物的结构，提出了两种生物转化途径。代谢组学数据显示，FS10在低、中、高剂量AFB(1)条件下表现出不同程度的生物修复作用。结果还表明，代谢产物谷胱甘肽在AFB(1)生物转化途径及其与AFB(1)形成AFB(2) - GOH的过程中起重要作用。从AFB(1)毒性位点的变化来看，这四种产物可能比AFB(1)毒性更低。因此，AFB(1)降解菌株FS10在食品和饲料产品中AFB(1)解毒方面具有巨大的应用潜力。