Mining Lactonase Gene from Aflatoxin B₁-Degrading Strain <i>Bacillus megaterium</i> and Degrading Properties of the Recombinant Enzyme

Abstract

Mycotoxins are toxic secondary metabolites mainly produced by filamentous fungal species that commonly contaminate food and feed. Aflatoxin B₁ (AFB₁) is extremely toxic and seriously threatens the health of humans and animals. In this work, the <i>Bacillus megaterium</i> HNGD-A6 was obtained and showed a 94.66% removal ability of AFB₁ by employing extracellular enzymes as the degrading active substance. The degradation products were P1 (AFD₁, C₁₆H₁₄O₅) and P2 (C₁₄H₁₆N₂O₂), and their toxicity was greatly reduced compared to that of AFB₁. The AttM gene was mined by BlastP comparison and successfully expressed in <i>Escherichia coli</i> BL21. AttM could degrade 86.78% of AFB₁ 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.