中文摘要：黄曲霉毒素（AF）B1污染食品和饲料，带来不利的经济和健康后果。微生物或微生物酶降解AFB₁是一个前景广阔的预防措施。为此，本研究测试了43株从玉米、水稻和土壤样品中采集的细菌降解AFB1的活性。活性最高的是L7菌株，经鉴定为嗜热芽孢杆菌。并从其煮过的上清液中纯化到一种耐热酶，命名为芽孢杆菌黄曲霉毒素降解酶（BADE）。这是首次报道从嗜热芽孢杆菌中分离到BADE，能够在加工食品和饲料的过程中降解黄曲霉毒素。
外文摘要：Food and feed contamination by aflatoxin (AF)B₁ has adverse economic and health consequences. AFB₁ degradation by microorganisms or microbial enzymes provides a promising preventive measure. To this end, the present study tested 43 bacterial isolates collected from maize, rice, and soil samples for AFB₁-reducing activity. The higher activity was detected in isolate L7, which was identified as Bacillus shackletonii. L7 reduced AFB₁, AFB₂, and AFM₁ levels by 92.1%, 84.1%, and 90.4%, respectively, after 72 h at 37 °C. The L7 culture supernatant degraded more AFB₁ than viable cells and cell extracts; and the degradation activity was reduced from 77.9% to 15.3% in the presence of proteinase K and sodium dodecyl sulphate. A thermostable enzyme purified from the boiled supernatant was designated as Bacillus aflatoxin-degrading enzyme (BADE). An overall 9.55-fold purification of BADE with a recovery of 39.92% and an activity of 3.85 × 10³ U·mg-1 was obtained using chromatography on DEAE-Sepharose. BADE had an estimated molecular mass of 22 kDa and exhibited the highest activity at 70 °C and pH 8.0, which was enhanced by Cu2+ and inhibited by Zn2+, Mn2+, Mg2+, and Li⁺. BADE is the major protein involved in AFB₁ detoxification. This is the first report of a BADE isolated from B. shackletonii, which has potential applications in the detoxification of aflatoxins during food and feed processing.
外文关键词：aflatoxin B-1；aflatoxin-degrading enzyme；biodegradation；Bacillus shackletonii；purification
作者：Xu, L；Ahmed, MFE；Sangare, L；Zhao, YJ；Selvaraj, JN；Xing, FG; Wang, Y；Yang, HP；Liu, Y
作者单位：Chinese Acad Agr Sci
期刊名称：TOXINS
期刊影响因子：3.571
出版年份：2017
出版刊次：1
点击下载：来自嗜热芽孢杆菌L7的新型黄曲霉毒素降解酶