Mining Lactonase Gene from Aflatoxin B<sub>1</sub>-Degrading Strain <i>Bacillus megaterium</i> and Degrading Properties of the Recombinant Enzyme
Sizhong Cheng, Tian Wu, Hongxin Zhang, Zhongke Sun, Fred Mwabulili, Yanli Xie, Shumin Sun, Weibin Ma, Qian Li, Yuhui Yang, Xingquan Wu, Hang Jia
Abstract
Mycotoxins are toxic secondary metabolites mainly produced by filamentous fungal species that commonly contaminate food and feed. Aflatoxin B 1 (AFB 1 ) is extremely toxic and seriously threatens the health of humans and animals. In this work, the Bacillus megaterium HNGD-A6 was obtained and showed a 94.66% removal ability of AFB 1 by employing extracellular enzymes as the degrading active substance. The degradation products were P1 (AFD 1, C 16 H 14 O 5 ) and P2 (C 14 H 16 N 2 O 2 ), and their toxicity was greatly reduced compared to that of AFB 1 . The AttM gene was mined by BlastP comparison and successfully expressed in Escherichia coli BL21. AttM could degrade 86.78% of AFB 1 at pH 8.5 and 80 °C, as well as 81.32% of ochratoxin A and 67.82% of zearalenone. The ability of AttM to degrade a wide range of toxins and its resistance to high temperatures offer the possibility of its use in food or feed applications.