Mining Lactonase Gene from Aflatoxin B 1 -Degrading Strain Bacillus megaterium and Degrading Properties of the Recombinant Enzyme

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.