Development of a genetic probe for polycyclic aromatic hydrocarbon-degrading Mycobacteria in soil

An environmental gene probe for the detection of polycyclic aromatic hydrocarbon (PAH)-metabolizing mycobacteria in native microbial communities of soils has been developed. Mycobacteria sp. JLS, MCS, and KMS are three strains of PAH-metabolizing bacteria that have been isolated from PAH-contaminated soil. They are shown to be able to mineralize 14C-labeled pyrene in a native soil. Gram staining, electron microscopy, and 16S rDNA-sequencing revealed that these bacteria are Mycobacterium strains. Mycobacteria species utilize dioxygenase enzyme systems as the first phase of the PAH degradation pathway. The PAH-induced dioxygenase system in Mycobacteria species is composed of at least two subunits nidA and nidB. Polymerase chain reaction (PCR) primers have been designed to specify the nidB and nidA genes. These primers have been used, along with an improved technique for extraction of DNA from selected soil systems, to indicate the presence of the dioxygenase gene complex in soils.