INHIBITION OF AFLATOXIN PRODUCTION OF ASPERGILLUS-PARASITICUS NRRL-2999 BY BACILLUS-PUMILUS

Six isolates of Bacillus pumilus were tested for their ability to inhi bit aflatoxin production of Aspergillus parasiticus NRRL 2999 in yeast extract sucrose (YES) broth. Aflatoxin production was inhibited in bo th simultaneous and deferred antagonism assays, suggesting that the in hibitory activity was due to extracellular metabolite(s) produced in c ell-free supernatant fluids of cultured broth. The inhibition was not due to organic acids or hydrogen peroxide produced by B. pumilus since the inhibitory activity was not lost after pH adjustment or treatment of supernatant fluids with catalase. A range of media tested for the production of inhibitory metabolite(s) in supernatant fluids showed th at all media supported bacterial growth and production of the metaboli te(s). The metabolite(s) were produced over a wide range of temperatur e (25 to 37 degrees C) and pH (4 to 9) of growth of B. pumilus. They w ere stable over a wide range of pH (4 to 10) and were not inactivated after autoclaving at 121 degrees C for 30 minutes.