EVIDENCE FOR DEGRADATION OF AFLATOXIN-B-1 BY FLAVOBACTERIUM-AURANTIACUM

The fate of [C-14]aflatoxin B-1 in the presence of Flavobacterium aurantiacum was determined. [C-14]aflatoxin B-1 was incubated with live or dead F. aurantiacum cells for up to 72 h. Samples were extracted with chloroform and the aqueous and non-polar phases were analyzed for C-14 content over time. The normally chloroform-soluble [C-14]aflatoxin B-1 is rapidly converted to water-soluble degradation products by live cells. Some radioactivity was initially associated with live cells but was lost at about the same rate as the water-soluble degradation products accumulated. The evolution of (CO2)-C-14 by the live cells provides further evidence that at least a portion of the [C-14]aflatoxin B-1 is metabolized. Dead F. aurantiacum cells bind some aflatoxin but are unable to carry out the degradation to water-soluble compounds or carbon dioxide.