To test the inactivation of the antibiotic, virginiamycin, by laccase-induced culture supernatants of Aureobasidium pullulans. Fourteen strains of A. pullulans from phylogenetic clade 7 were tested for laccase production. Three laccase-producing strains from this group and three previously identified strains from clade 5 were compared for inactivation of virginiamycin. Laccase-induced culture supernatants from clade 7 strains were more effective at inactivation of virginiamycin, particularly at 50 A degrees C. Clade 7 strain NRRL Y-2567 inactivated 6 A mu g virginiamycin/ml within 24 h. HPLC analyses indicated that virginiamycin was degraded by A. pullulans. A. pullulans has the potential for the bioremediation of virginiamycin-contaminated materials, such as distiller's dry grains with solubles (DDGS) animal feed produced from corn-based fuel ethanol production.