GENETIC-CONTROL OF NAPHTHALENE BIODEGRADA TION IN PSEUDOMONAS SP 8909N STRAIN

The ability of Pseudomonas sp. 8909N to grow using Naphthalene and sal icylate as the sole source of carbon and energy is mediated by the pre sence of an 80-kb conjugative pBS1145 plasmid in this strain. Structur al genes for naphthalene degradation in pBS1145 plasmid are homologous to those in the known NAH7 plasmid. Conjugational transfer of pBS1145 from the original strain is accompanied by a deletion of a plasmid DN A fragment that does not affect the Nah(+)Sal(+) phenotype. Plasmid pB S1145 specifies a low constitutive level of catechol-2,3-dioxygenase, the key enzyme of the metha-pathway of catechol degradation. Activity of this enzyme is induced in the presence of salicylate. Enzymes of bo th the metha and ortho-pathway of catechol degradation (catechol-2,3-d ioxygenase) were shown to operate in the process of naphthalene degrad ation in Pseudomonas sp. 8909N. The ability of this strain to bring ab out transformation of polycyclic aromatic hydrocarbon phenanthrene is also controlled by pBS1145 plasmid.