Detection of polycyclic aromatic hydrocarbon degradation genes in different soil bacteria by polymerase chain reaction and DNA hybridization

Twenty different strains of Pseudomonas, Mycobacterium, Gordona, Sphingomon as, Rhodococcus and Xanthomonas which degrade polycyclic aromatic hydrocarb ons (PAH) were characterized in respect to genes encoding degradation enzym es for PAM. Genomic DNA from these strains was hybridized with a fragment o f ndoB, coding for the large iron sulfur protein (ISP alpha) of the naphtha lene dioxygenase from Pseudomonas putida PaW736 (NCIB 9816). A group of sev en naphthalene degrading Pseudomonas strains showed strong hybridization wi th the ndoB probe, and five Gordona, Mycobacterium, Rhodococcus and Pseudom onas strains able to degrade higher molecular weight PAH showed weaker hybr idization signals. Using a polymerase chain reaction (PCR) approach, seven naphthalene-degrading Pseudomonas strains showed a PCR fragment of the expe cted size with ndoB-specific primers and additionally ten strains of Gordon a, Mycobacterium, Pseudomonas, Sphingomanas and Xanthomonas able to degrade higher molecular weight PAH were detected with degenerate primer-pools spe cific for the ISP alpha [2Fe-2S]-Rieske center of diverse aromatic hydrocar bon dioxygenases. This suggests a molecular relationship between genes codi ng for PAH catabolism in various PAM-degrading bacterial laxa, which could be used to evaluate the PAM-degradation potential of mixed populations. (C) 1999 Federation of European Microbiological Societies, Published by Elsevi er Science B.V. All rights reserved.