A method for determining whether a microorganism is capable of biodegrading a contaminant can include the following: providing a first set of DNA molecules consisting of fragments of genomic DNA of a contaminant-degrading mycobacterium; contacting under hybridizing conditions, the first set of DNA molecules with a second set of DNA molecules consisting of genomic DNA of a microorganism, wherein it is not known whether or not the microorganism biodegrades a contaminant; and detecting hybridization between the first set of DNA molecules and the second set of DNA molecules, wherein the hybridization between the first and second sets is an indication that the microorganism is capable of biodegrading a contaminant.