In vitro degradation of aflatoxin B-1 by horse radish peroxidase

Aflatoxin B-1 (AFB(1)), extracted from Aspergillus flavus ATCC 15517, was d etoxified up to 60% by commercial horse radish peroxidase (HRP) (200 U/mg) in vitro. Partially purified peroxidase enzymes from freshly harvested radi sh root having 20 and 30 U/mg of protein were made to act upon the toxin in vitro and showed approximately 30 and 38% conversion, respectively. The op timum enzymatic reaction occurred in 50 mM phosphate buffer at 20 degrees C , pH6, incubation time 60 min and normal pressure. Hydrogen peroxide in 5 m M concentration was used as oxidising agent in all the reactions performed. The reaction product was tested for its toxicity on Bacillus megaterium an d other micro-organisms. Toxicity tests resulted in 97 and 30% growth of ba cilli when 200 and 30 U/mg enzyme was used for the reaction, respectively. (C) 1999 Elsevier Science Ltd. All rights reserved.