J. Sanseverino et al., PLASMID-MEDIATED MINERALIZATION OF NAPHTHALENE, PHENANTHRENE, AND ANTHRACENE, Applied and environmental microbiology, 59(6), 1993, pp. 1931-1937
The well-characterized plasmid-encoded naphthalene degradation pathway
in Pseudomonas putida PpG7(NAH7) was used to investigate the role of
the NAH plasmid-encoded pathway in mineralizing phenanthrene and anthr
acene. Three Pseudomonas strains, designated 5R, DFC49, and DFC50, wer
e recovered from a polynuclear aromatic hydrocarbon-degrading inoculum
developed from a manufactured gas plant soil slurry reactor. Plasmids
pKA1, pKA2, and pKA3, approximately 100 kb in size, were isolated fro
m these strains and characterized. These plasmids have homologous regi
ons of upper and lower NAH7 plasmid catabolic genes. By conjugation ex
periments, these plasmids, including NAH7, have been shown to encode t
he genotype for mineralization of [9-C-14]phenanthrene and [U-C-14]ant
hracene, as well as [1-C-14]naphthalene. One strain, Pseudomonas fluor
escens 5RL, which has the complete lower pathway inactivated by transp
oson insertion in nahG, accumulated a metabolite from phenanthrene and
anthracene degradation. This is the first direct evidence to indicate
that the NAH plasmid-encoded catabolic genes are involved in degradat
ion of polynuclear aromatic hydrocarbons other than naphthalene.