Pseudomonas stutzeri F4 is capable of removing aflatoxin B1 efficiently.The properties and the kinetics of aflatoxin B1 hydrolyzed by F4,and the influence of proteinase K and SDS on its degradation performance were investigated.After 72 h of cultivation,80.03% of AFB1 was degraded by F4 cell suspension.Proteinase K had no affects on its degradation efficiency,while the degradation ability almost lost by SDS treatment.In addition,the cell-free supernatant of the degradation solution taken from different time also had the detoxification activity,and in which 60 h sample showed a better activity(84.30% AFB1 was degraded after continuous cultivation for 48 h).When the supernatant treated with proteinase K,the degradation efficiency was decreased to 45.42%.Low concentration of AFB1 induction had no effect on the degradation activity.These results indicated that a F4 intracellular enzyme was responsible for the degradation of AFB1.Meanwhile,HPLC chromatograms demonstrated that AFB1 was degraded to at least two products.