Degradation of aflatoxin B₁ by a newly isolated bacterium Paraburkholderia sp. MH-1

Aflatoxin B₁ (AFB₁), the most harmful mycotoxin found in food and feed, poses significant global health risks due to its toxic, mutagenic, teratogenic, and carcinogenic effects on both humans and livestock. Bacteria capable of degrading AFB₁ play a critical role in AFB₁ detoxification. In this study, an AFB₁-degrading bacterium, designated as Paraburkholderia sp. MH-1, was isolated. Strain MH-1 degraded 84.67 ± 2.94 % of AFB₁ (1.0 mg L^-1) after 96 h of incubation at 30°C, and it could tolerate AFB₁ concentrations of up to 20 mg L^-1. The optimum pH range, temperature, and NaCl concentration for AFB₁ biotransformation by strain MH-1 were 8.0-10.0, 30℃, and 0-0.5 % (m/v), respectively. Furthermore, 1 mM Cr³⁺ and Zn²⁺ significantly inhibited the transformation of AFB₁. The zebrafish assay was utilized to evaluate the toxicity of AFB₁ degradation products, revealing significantly reduced harmful effects compared to the parent AFB₁. Moreover, strain MH-1 has shown potential as a bioremediation reagent by effectively reducing AFB₁ contamination levels in animal feed. Two putative dye-decolorizing peroxidase (DyP) encoding genes were discovered in the genome of strain MH-1. Comparative genomic analysis showed the widespread presence of DyP in Paraburkholderia. These findings propose that strain MH-1 is a viable candidate for the effective removal of AFB₁ from contaminated animal feed.