Degradation of aflatoxin B1 by cell-free extracts of Rhodococcus erythropolis and Mycobacterium fluoranthenivorans sp nov DSM44556T

Biological degradation of aflatoxin B-1 (AFB(1)) by Rhodococcus erythropolis was examined in liquid cultures and in cell-free extracts. Dramatic reduction of AFB(1) was observed during incubation in the presence of R. erythropolis cells (17% residual AFB(1) after 48 h and only 3-6% residual AFB(1) after 72 h). Cell-free extracts of four bacterial strains, R. erythropolis DSM 14303, Nocardia corynebacterioides DSM 12676, N. corynebacterioides DSM 2015 1, and Mycobacterium fluoranthenivorans sp. nov. DSM 44556(T) were produced by disrupting cells in a French pressure cell. The ability of crude cell-free extracts to degrade AFB(1) was studied under different incubation conditions. Aftatoxin B-1 was effectively degraded by cell free extracts of all four bacterial strains. N. corynebacterioides DSM 12676 (formerly erroneously classified as Flavobacterium aurantiacum) showed the lowest degradation ability (60%) after 24 h, while >90% degradation was observed with N. corynebacterioides DSM 20151 over the same time, R. erythropolis and M fluoranthenivorans sp. nov. DSM 44556(T) have shown more than 90% degradation of AFB(1) within 4 h at 30 degrees C, whilst after 8 h AFB(1) was practicably not detectable. The high degradation rate and wide temperature range for degradation by R. erythropolis DSM 14303 and M fluoranthenivorans sp. nov. DSM 44556(T) indicate potential for application in food and feed processing. (c) 2005 Elsevier B.V. All rights reserved.