AUTHOR=Tang Ying , Liu Xiaojing , Dong Ling , He Shengran 

TITLE=Screening and identification of an aflatoxin B1-degrading strain from the Qinghai-Tibet Plateau and biodegradation products analysis

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1367297

DOI=10.3389/fmicb.2024.1367297

ISSN=1664-302X

ABSTRACT=<p>This research aimed to address the issue of aflatoxin B<sub>1</sub> (AFB<sub>1</sub>) contamination, which posed severe health and economic consequences. This study involved exploring unique species resources in the Qinghai-Tibet Plateau, screening strains capable of degrading AFB<sub>1</sub>. UPLC-Q-Orbitrap HRMS and NMR were employed to examine the degradation process and identify the structure of the degradation products. Results showed that <italic>Bacillus amyloliquefaciens</italic> YUAD7, isolated from yak dung in the Qinghai-Tibet Plateau, removed 91.7% of AFB<sub>1</sub> from TSB-AFB<sub>1</sub> medium with an AFB<sub>1</sub> concentration of 10 μg/mL (72 h, 37°C, pH 6.8) and over 85% of AFB<sub>1</sub> from real food samples at 10 μg/g (72 h, 37°C), exhibiting strong AFB<sub>1</sub> degradation activity. <italic>Bacillus amyloliquefaciens</italic> YUAD7’s extracellular secretions played a major role in AFB<sub>1</sub> degradation mediated and could still degrade AFB<sub>1</sub> by 43.16% after boiling for 20 min. Moreover, <italic>B. amyloliquefaciens</italic> YUAD7 demonstrated the capability to decompose AFB<sub>1</sub> through processes such as hydrogenation, enzyme modification, and the elimination of the -CO group, resulting in the formation of smaller non-toxic molecules. Identified products include C<sub>12</sub>H<sub>14</sub>O<sub>4</sub>, C<sub>5</sub>H<sub>12</sub>N<sub>2</sub>O<sub>2</sub>, C<sub>10</sub>H<sub>14</sub>O<sub>2</sub>, C<sub>4</sub>H<sub>12</sub>N<sub>2</sub>O, with a structure consisting of dimethoxyphenyl and enoic acid, dimethyl-amino and ethyl carbamate, polyunsaturated fatty acid, and aminomethyl. The results indicated that <italic>B. amyloliquefaciens</italic> YUAD7 could be a potentially valuable strain for industrial-scale biodegradation of AFB<sub>1</sub> and providing technical support and new perspectives for research on biodegradation products.</p>