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

Aflatoxin B1 (AFB1) 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% AFB1 degradation rate. Treatment with proteinase K, sodium dodecyl sulfate, and trichloroacetic acid decreased the AFB1 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 AFB1 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 AFB1 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 AFB1 was biotransformed into structurally different compounds, (C17H16O6), (C16H14O5), (C17H14O5), and (C16H10O6). According to the structure-activity relationship, these degradation products were produced by the destruction of partial toxic sites of AFB1, so the toxicity of these products may be lower than that of AFB1. Thus, P. aeruginosa M-4 has excellent potential for application in the detoxification of AFB1 in food and feed.