Isolation and Aflatoxin B1-Degradation Characteristics of a Microbacterium proteolyticum B204 Strain from Bovine Faeces

Aflatoxin B(1) (AFB(1)) is one of the most harmful mycotoxins, raising serious global health and economic problems. Searching for biological approaches for effective and safe AFB(1) degradation is imminent. In our study, Microbacterium proteolyticum B204 isolated from bovine faeces degraded 77% of AFB(1) after 24 h, becoming the first reported bacteria from the Microbacterium family to possess AFB(1) degradation characteristics. Temperature variation showed little effect on its degradation ratio, demonstrating high thermostability of 75% and 79% after boiling and sterilization, respectively. We suppose that the components playing a key role during this process were proteins, considering the decreased degradation rate caused by Proteinase K. Cell viability detection on HepG2 cells indicated that the degradation products were much less toxic than pure AFB(1). Furthermore, B204 cell-free culture supernatant also degraded AFB(1)-contaminated food, such as peanuts, corn and cheese. These results suggested that this strain with AFB(1) degradation properties could be a prospective candidate for application in the food and feed industries.