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

Abstract

Biological degradation of aflatoxin B1 (AFB1) by Rhodococcus erythropolis was examined in liquid cultures and in cell-free extracts. Dramatic reduction of AFB1 was observed during incubation in the presence of R. erythropolis cells (17% residual AFB1 after 48 h and only 3–6% residual AFB1 after 72 h). Cell-free extracts of four bacterial strains, R. erythropolis DSM 14303, Nocardia corynebacterioides DSM 12676, N. corynebacterioides DSM 20151, and Mycobacterium fluoranthenivorans sp. nov. DSM 44556T were produced by disrupting cells in a French pressure cell. The ability of crude cell-free extracts to degrade AFB1 was studied under different incubation conditions. Aflatoxin B1 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 N90% degradation was observed with N. corynebacterioides DSM 20151 over the same time. R. erythropolis and M. fluoranthenivorans sp. nov. DSM 44556T have shown more than 90% degradation of AFB1 within 4 h at 30 8C, whilst after 8 h AFB1 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 44556T indicate potential for application in food and feed processing