Naphthalene degradation through the gentisate pathway by Burkholderia cepacia strain JS150

This research was conducted to identify the metabolic pathway used by Burkholderia cepacia strain JS150 for catabolism of naphthalene and salicylate. The relationship between the naphthalene pathway and pathways for the catabolism of other aromatic compounds by JS150 was also investigated. DNA-DNA hybridization under high stringency conditions revealed significant homology between JS150 DNA and the nahA gene of naphthalene catabolic plasmid NAH7. JS150 DNA did not, however, hybridize to nahG or nahR probes. Gentisate was detected in culture medium by HPLC and GO-MS when the growth substrate was either naphthalene or salicylate. Gentisate dioxygenase, but not catechol 1,2- or 2,3-dioxygenase, was induced by growth on salicylate. Complete degradation of gentisate by extracts of induced cells was shown to be dependent on the presence of reduced glutathione. The above results indicate that JS150 degrades naphthalene and salicylate through a reduced glutathione-dependent gentisate pathway. No other role for the gentisate pathway in JS150 was identified. m-hydroxybenzoate, which is degraded through the gentisate pathway by some bacteria, was found to be degraded through protocatechuate ortho cleavage in JS150. Anthranilic acid, another potential gentisate pathway substrate, was also shown not to be degraded through the gentisate pathway in JS150. The actual catabolic pathway for anthranilic acid was not identified.