[Isolation, identification of a pyrene-degrading strain Mycobacterium sp. M11 and its degrading characteristics]

A bacterial strain M11 using phenanthrene, anthracene, fluorethene,pyrene as a sole carbon and energy sources was isolated from soils contaminated with polycyclic aromatic hydrocarbons. Strain M11 was identified as Mycobacterium sp. according to the results of morphology, physiology and the phylogenetical analyses of 16S rDNA sequence. The degradation rate of pyrene (at levels of 50 mg/L, 100 mg/L and 200 mg/L) by strain M11 was 76.9%, 91.8% and 79.23% within 16 d in broth assay. Mycobacterium sp. M11 showed a strong ability to grow from pH 5 to pH 9 in liquid minimal medium containing pyrene 100 mg/L. Mycobacterium sp. M11 possessed aromatic-ring dioxygenase genes, which are highly homologous to the known nidAB genes from pyrene-degrading Mycobacteria.