Efficient Aflatoxin B1 degradation by a novel isolate, Pseudomonas aeruginosa M-4

Aflatoxin B 1 (AFB 1 ) is the most common mycotoxin with the highest toxicity, posing a threat for food contamination. In this study, the bacterium Pseudomonas aeruginosa M-4 was isolated from rotten wood, and its culture supernatant showed a 56.79% AFB 1 degradation rate. Treatment with proteinase K, sodium dodecyl sulfate, and trichloroacetic acid decreased the AFB 1 degradation rate in the culture supernatant to 20.71%, 10.83%, and 19.62%, respectively. Moreover, heating the culture supernatant at 121 °C for 30 min increased in the AFB 1 degradation rate to 84.76%, indicating effective degradation by heat-resistant and inducible extracellular proteins or enzymes. P. aeruginosa M-4 reduced the content of AFB 1 in contaminated maize (90.57%, 14 d). Additionally, high-performance liquid chromatography and ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry analyses showed that AFB 1 was biotransformed into structurally different compounds, (C 17 H 16 O 6 ), (C 16 H 14 O 5 ), (C 17 H 14 O 5 ), and (C 16 H 10 O 6 ). According to the structure-activity relationship, these degradation products were produced by the destruction of partial toxic sites of AFB 1 , so the toxicity of these products may be lower than that of AFB 1 . Thus, P . aeruginosa M-4 has excellent potential for application in the detoxification of AFB 1 in food and feed.