Degradation of a mixture of high-molecular-weight polycyclic aromatic hydrocarbons by a Mycobacterium strain PYR-1

Mycobacterium sp. PYR-1, which was previously shown to mineralized several individual polycyclic aromatic hydrocarbons (PAHs), simultaneously degraded phenanthrene, anthracene, fluoranthene, pyrene and benzo[a]pyrene in a six component synthetic mixture. When provided with a complex carbon source, Mycobacterium sp. PYR-1 degraded greater than 74% of the total PAH mixture during 6 d of incubation. Mycobacterium sp. PYR-1 appeared to preferentially degrade phenanthrene. No significant difference in degradation rates was observed between fluoranthene and pyrene. Anthracene degradation was slightly delayed but, once initiated, proceeded at a constant rate. Benzo[a]pyrene was degraded slowly. Degradation of a crude mixture of benzene-soluble PAHs from contaminated sediments resulted is 47% reduction of the material in 6 d compared with that autoclaved controls.