Preparation, purification and characteristics of an aflatoxin degradation enzyme from Myxococcus fulvus ANSM068

Aims: To prepare, purify and characterize an extracellular enzyme from Myxococcus fulvus ANSM068, designated as myxobacteria aflatoxin degradation enzyme (MADE), which possesses degradation activity against aflatoxin B-1 (AFB(1)), G(1) (AFG(1)) and M-1 (AFM(1)) in solution. Methods and Results: The culture supernatant of strain M. fulvus demonstrated high degradation ability against AFB(1) (71 center dot 89%), AFG(1) (68 center dot 13%) and AFM(1) (63 center dot 82%) after 48 h of incubation. An enzyme was purified from the supernatant of M. fulvus using ethanol precipitation and chromatography on DEAE-Sepharose and Superdex 75. An overall 166-fold purification of the enzyme with a recovery of 57% and a final specific activity of 569 center dot 44 x 103 U mg-1 was obtained using the present purification protocol. The apparent molecular mass of MADE was estimated to be 32 kDa by SDS-PAGE. AFG(1) and AFM(1) were significantly degraded, by 96 center dot 96 and 95 center dot 80%, respectively, when treated with pure MADE (100 U ml-1) produced by strain ANSM068. MADE exhibited the largest amount of activity at 35 degrees C and pH 6 center dot 0, with Mg2+ ions greatly promoting and Zn2+ strongly inhibiting MADE activity. Conclusions: An aflatoxin degradation enzyme from bacterial isolates can effectively remove aflatoxin B-1, G(1) and M-1 in solution. Significance and Impact of the Study: The high activity and wide temperature and pH range of MADE for the degradation of aflatoxin have promising applications in control of mycotoxins during food and feed processing.