Growth conditions of and emetic toxin production by Bacillus cereus in a defined medium with amino acids

The growth and emetic toxin (cereulide) production of Bacillus cereus strai ns in defined culture media were studied. We found that a fully synthetic m edium (CADM) allowed the production of emetic toxin and the addition of glu cose enhanced it, By subtracting each amino acid from CADM, we found that o nly three amino acids, valine, leucine and threonine, were essential for gr owth and toxin production by B. cereus. The addition of high levels (50 mM) of leucine, isoleucine and glutamic acid decreased the toxin production, O ther amino acids had no effect at this concentration.