施氏假单胞菌F4对黄曲霉毒素B_1的酶解作用及其降解产物的初步分析

Enzymolysis of aflatoxin B_1 by Pseudomonas stutzeri F4 and analysis of the degrading products

施氏假单胞菌F4能高效降解黄曲霉毒素B1(aflatoxin B1,AFB1)。研究了F4的AFB1降解活性、降解动力学以及蛋白酶K和SDS对其降解性能的影响。F4细胞悬液与毒素共培养72 h后降解率达80.03%;蛋白酶K处理对降解率没有影响,SDS处理的细胞悬液基本丧失了降解活性。不同时间点的降解液上清液仍能有效降解残留AFB1,其中以60 h的降解液上清液活性较好,与残留AFB1继续作用48 h后降解率达84.30%;而经蛋白酶K处理后降解率仅为45.42%。低浓度AFB1诱导对菌体的降解活性没有影响。上述结果提示,F4通过胞内酶作用降解AFB1。高效液相色谱对产物分析表明,F4可将AFB1酶解为至少2种产物。

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 in- vestigated. After 72 h of cultivation, 80.03% of AFB1 was degraded by F4 cell suspension. Proteinase K had no af- fects 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 AFB~ 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.