| The ability of crude protein extracts, obtained from the enzymatic lysis of F. aurantiacum, to remove Aflatoxin B1 (AB 1) and Aflatoxin B2 (AB2) was investigated. Crude protein extracts (800 mug/ml total protein), prepared by enzymatic lysis (0.5 mg/ml lysozyme) of a 48 h culture, removed 83% of AB1 and 78% of AB2 from aqueous solution after 24 h incubation. Ammonium sulfate precipitation, size exclusion chromatography, anion exchange chromatography, and membrane filtration were used to separate proteins from crude protein extracts from F. aurantiacum&dotbelow;. Precipitated proteins corresponding to 60% saturation with ammonium sulfate degraded an average of 72% of AB1 during 24 h incubation at 30°C. Some AB1 degradation activity was observed at 20, 40, 80, and 100% saturation as well. The elution of crude protein extracts through DEAE cellulose using increasing concentrations of NaCl yielded multiple peaks. Two peaks, corresponding to pooled fraction 65--150 minutes and 155--175 minutes degraded approximately 40--45% of AB1 from aqueous solution during 24 h incubation at 30°C. Elution of crude protein extracts through Sephadex G-125 yielded multiple peaks. The peak corresponding to pooled volumes of 100.8--109.2 mL decreased AB1 by 63%. Two other gel filtration fractions demonstrated considerable activity. The peak corresponding to pooled volumes of 27.3--42 mL decreased AB1 by 44.5% and the peak corresponding to pooled volumes of 81.9--88.2 decreased AB1 38%. Ultra-filtration indicated that the protein responsible for AB1 degradation was between 50 and 20 kD. |
